# Road Racing & Aero Wheels



## September (3 Feb 2015)

Hello,

I'm going to be taking part in this years annual local road race league and aside from getting as fit and as strong as possible, I was thinking of making a few modifications to my Cannondale CAAD8.

We all know that one of the single best modifications you can make to a bike is improved wheels, so that's what I am going to do.

However, I'm getting quite drawn to aero wheels (and these in particular: http://wheelsmith.co.uk/aero-50-clincher).

I know people say aero wheels can hinder your climbing - and I've read about that to death.

But I was wondering if these were a good/bad idea for a road league?

I'm guessing they can't do any harm but then again, you don't see many other rides using aero wheels in the league.

Good and bad, I was after peoples opinions on this and any potential alternative options.

Thank you!


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## Rob3rt (3 Feb 2015)

Depends on the courses you will be riding etc as to what wheel will be best, 50mm is a pretty standard rim depth these days. People ride all sorts of stuff, from real basic, to real bling, the most important thing is to only race on kit you can afford to replace (or insure).


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## shadow master (3 Feb 2015)

Good quality light,stiff, 50mm wheels, aero well and don't hinder climbing too much,The biggest factor people don't realise is the effect crosswinds have on aero's at 50mm plus,tests are carried out in wind tunnels,not in the real world,if your feeling the bike swating/twitching,you'll probably slow down by 4/5 mph,at that point the aero's are costing you speed, if you then have heavy ones eg 2000grams a pair,you lose on the climbs as well!.....just something to think about!


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## Rob3rt (3 Feb 2015)

You will not reduce speed by 4-5 mph... where on earth have you pulled that nugget from.

Riding in full aero gear, in a time trial, if the wind is such that I have to sit up and get hold of the outriggers to control the bike, I lose nowhere near 4-5 mph, so someone already using a wide grip, riding a less extreme set of wheels and not having to undergo a dramatic change in riding position is going to loose much less speed!


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## Yellow Saddle (3 Feb 2015)

shadow master said:


> Good quality light,stiff, 50mm wheels, aero well and don't hinder climbing too much,The biggest factor people don't realise is the effect crosswinds have on aero's at 50mm plus,tests are carried out in wind tunnels,not in the real world,if your feeling the bike swating/twitching,you'll probably slow down by 4/5 mph,at that point the aero's are costing you speed, if you then have heavy ones eg 2000grams a pair,you lose on the climbs as well!.....just something to think about!



Stiff? 
Don't hinder climbing much?

What does this stuff mean? Can you quantify it?
In which plane/direction is it stiff or not stiff?
How would you notice non-stiffness in wheels?
How much do they hinder climbing and why? 

More nonsense is spoken about wheels than astrology, it seems.


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## Yellow Saddle (3 Feb 2015)

September said:


> Hello,
> 
> I'm going to be taking part in this years annual local road race league and aside from getting as fit and as strong as possible, I was thinking of making a few modifications to my Cannondale CAAD8.
> 
> ...




If you really want to improve in the league, get a coach, not new wheels. Whatever wheels you have on that bike will be good enough to move you up 100 places in position if you have the right training program and follow it.


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## Joshua Plumtree (3 Feb 2015)

What is this local road race league of which you speak? 

If it involves lots of group riding, surges off the front and breakaways, then surely you'd be looking to purchase lightweight high quality wheels which accelerate quickly from an already fast pace. 
Not convinced deep profile wheels would be of any benefit.


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## Yellow Saddle (3 Feb 2015)

Joshua Plumtree said:


> What is this local road race league of which you speak?
> 
> If it involves lots of group riding, surges off the front and breakaways, then surely you'd be looking to purchase lightweight high quality wheels which accelerate quickly from an already fast pace.
> Not convinced deep profile wheels would be of any benefit.


Have you ever done the calculation to see how much power is consumed by accelerating slightly lighter wheels? It is very, very little and no different from accelerating weight anywhere else on the bike bar a few micro milli watts. Further accelerating them from any given speed requires the same energy. Your starting speed has nothing to do with it. Wheels are over rated in amateur circles, no matter what you spend on them. They only offer brag value, especially if they're expensive and the brand is well known.


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## midlife (3 Feb 2015)

Depends on the race but tactics seemed to play quite a big part when I did road racing in the 70's 

Time Trailling off the front like Phil Bayton was never a good tactic but I always fancied it  Always got beaten by some lazy sod who was good at sprinting 

Shaun


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## Joshua Plumtree (3 Feb 2015)

Yellow Saddle said:


> Have you ever done the calculation to see how much power is consumed by accelerating slightly lighter wheels? It is very, very little and no different from accelerating weight anywhere else on the bike bar a few micro milli watts. Further accelerating them from any given speed requires the same energy. Your starting speed has nothing to do with it. Wheels are over rated in amateur circles, no matter what you spend on them. They only offer brag value, especially if they're expensive and the brand is well known.



Not clever enough to do the calculation! But I'm prepared to take your word for it, although it does seem a little counter-intuitive!


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## wam68 (3 Feb 2015)

shadow master said:


> Good quality light,stiff, 50mm wheels, aero well and don't hinder climbing too much,The biggest factor people don't realise is the effect crosswinds have on aero's at 50mm plus,tests are carried out in wind tunnels,not in the real world,if your feeling the bike swating/twitching,you'll probably slow down by 4/5 mph,at that point the aero's are costing you speed, if you then have heavy ones eg 2000grams a pair,you lose on the climbs as well!.....just something to think about!


Have to agree with you on that and an excellent point. It scares the proverbial out of you. Certainly makes me wind my neck in for a while and whether we are prepared to admit it or not it will slow you down.


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## shadow master (3 Feb 2015)

Yellow Saddle said:


> Stiff?
> Don't hinder climbing much?
> 
> What does this stuff mean? Can you quantify it?
> ...


I have experienced budget aero wheels that when standing to crest a hill actually flex enough to rub on the brake from one side to the other,at lower speeds,ie climbing,The perphiael


Yellow Saddle said:


> Stiff?
> Don't hinder climbing much?
> 
> What does this stuff mean? Can you quantify it?
> ...


Yes I can quantify this with a simple example,I have ridden a good carbon bike with budget 38mm alloy aero wheels, weight 2500grams a pair,The wheels flex and rub on the back brake when standing climbing,The 38mm has very little aero ability at higher speeds, but your still carrying the peripheral weight of the cheap rim on low speed climbs!so in short the benefits of budget 38mm wheels are negligible, and that's what the op is asking!


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## shadow master (3 Feb 2015)

Rob3rt said:


> You will not reduce speed by 4-5 mph... where on earth have you pulled that nugget from.
> 
> Riding in full aero gear, in a time trial, if the wind is such that I have to sit up and get hold of the outriggers to control the bike, I lose nowhere near 4-5 mph, so someone already using a wide grip, riding a less extreme set of wheels and not having to undergo a dramatic change in riding position is going to loose much less speed!


Fear of the crosswinds and falling from the bike is subjective,but someone using aero wheel's for the first time in windy conditions,will be alarmed to say the least!and certainly lose more speed than the aero advantage creates,I'm not talking about a pro rider,because the op clearly isn't!


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## Spoked Wheels (3 Feb 2015)

Yellow Saddle said:


> Stiff?
> Don't hinder climbing much?
> 
> What does this stuff mean? Can you quantify it?
> ...


I'm surprised you are asking some of these questions. 
Vertical is not much of an issue if any at all with deep rims but lateral stiffness is another matter. Asking what is stiffness or how would you notice non-stiffness, like you never heard of wheel flexing is annoying (coming from somebody that keeps telling us that knows everything about wheel building) added to that the tone of your questioning, makes you sound arrogant.

I do agree with your advice to spend the money on a good coach instead. That to me sounds like the best advice given to the OP.


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## gds58 (3 Feb 2015)

Yellow Saddle said:


> Stiff?
> Don't hinder climbing much?
> 
> What does this stuff mean? Can you quantify it?
> ...


Oh dear Oh dear, if you need to ask these questions Yellow Saddle then you shouldn't really be contributing to this thread as you clearly don't know enough about the subject matter anyway.
I'm sure there will be plenty enough answers from other members who do have both the knowledge and the experience to help you. I have raced at National level and currently work in the Cycling trade so OP if you would like to message me directly I'll help with whatever advice I can on this subject.
G


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## zizou (3 Feb 2015)

If the wheels are purely for racing then alot of people go for tubs rather than clinchers. However if using the wheels outside of racing too then i'd sway towards the clinchers as they are alot more convienient. For aero clinchers then i'd take the slight weight penalty and go for something with an aluminium brake track rather than an all carbon one. Some will disagree but carbon clinchers IMO have more downsides than upsides.

Depends also on what sort of rider you are plus what the races are like. Are you light / heavy / powerful? Are you a sprinter or a climber? Are you courses hilly? Are they circuits? Are they circuits with tight corners? All that adds up to different choices, some of it just preference.


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## Yellow Saddle (8 Feb 2015)

Of all the scientific or pseudo/marketing scientific issues that divide cyclists, wheels must be right there at the top.

The story usually goes like this:

Someone asks what wheels he or she should “upgrade” to. This person is typically a beginner, who unfortunately read a bicycle magazine somewhere and got the wrong impression about wheels.

Several answers ensue but these can all be divided into two classes.


Those who recommend XYZ wheels based on what they’ve purchased and “so far no issues, therefore...” and;


Those who recite the old myths of rotational weight and aerodynamics and make recommendations based on wheels with the lowest of these two characteristics.
What you never find in these posts are rational answers based on realistic science. Nor can any amount of coaxing entice the advisers to justify their recommendations or opinions. So, let’s try and look at the issue objectively. I’ll make some assumptions.


The OP is an amateur and probably Joe Average or Joe Beginner. The OP is not a time-triallist, tri-athlete, world hour record candidate or particularly talented and performs long solo break-aways at the head of a pursuing bunch.


The OP does not have 8% body fat but typically double that.


The OP is not a lightweight but probably average i.e. 70 kgs or above.


The OP is not yet flexible enough to get very aero on the bike and doesn’t even feel comfortable in the drops.


The OP’s average ride speed is 26 kph (http://tinyurl.com/jwnhr9n).


The is nothing wrong with the OP’s current wheels.
Let’s deal with the recommendations based on ownership. The premise here is always that “these worked for me so therefore it will work for you.” They encourage the OP to make a meaningless upgrade without understanding why the OP even needs to change wheels. If there is a real need and a special one, what works for you won’t work for the OP. Sometimes these recommendations are pseuo-justified. “These XYZs roll nicely.” “These XYZs of mine are really responsive.” These are meaningless, unquantifiable terms. Often they even contain ridiculous conflicts. “Really stiff by very comfortable/Compliant.” Those properties are opposing.

Anyway, most of these recommendations are given with good intentions but that doesn’t mean they may not be questioned.

Let’s move on to the real pseudo-science – light, stiff, aero, fast etc etc.

*Rolling resistance:* Bearing resistance is an extremely small portion of the overall rolling resistance in a bicycle wheel. Drag here is in the order of one or two grams whereas drag from wind resistance could be a hundred times that. And then only at high speed. I again refer you to the nation’s average speed for competitive riders – 26 kph. A pro peloton goes 50kph. Aero drag increase with the square of speed. Going at 50kph requires four times more horsepower than going at 25kph. In other words, at low speed, aerodynamics is just not an issue at all. Nada.

A thin race tyre pumped at 8 bar gives you better improvements in rolling resistance than an expensive ceramic bearing.

Then, it is impossible to perceive differences in rolling resistance or aerodynamics between different wheels on a bicycle, so saying that “my XYZ wheels roll really fast” is nonsense. Obviously I’m excluding the outriggers in the bell curve but we’re not comparing cheap plastic BMX wheels with permatubes inside knobbly tyres here in anyway.

*Aerodynamics: *It is of course true that rims with larger profiles and wheels with lower spoke count have better aerodynamics but aerodynamics is just not important to Joe Average. Have a look at his statistics at the beginning of this article. He/she doesn’t go 50kph. Deep section rims are problematic too. They have to be made from carbon in order to bring them in at any reasonable weight. This increases costs, decreases braking performance significantly, reduces durability and is unsuitable for commuting and riding where there could be potholes. Carbon wheels are just not practical. Further, any aerodynamic wheel is almost certainly a proprietary wheel. Hub spares, spokes and rims are all a manufacturer’s part number and can only be obtained from the manufacturer itself. This increases repair costs and waiting time. A standard J-spoke wheel using 32-spokes on a common hub, laced with standard double-butted spokes on a common rim is worth its weight in gold when it comes to repairs.

*Stiffness* is never an issue in bicycle wheels unless the wheels are stupid to start off with. If they don’t touch the seatstays, chainstays or fork, then they are stiff enough for the job. No energy is lost from a little bit of flex (it is an elastic deformation and the energy is returned). Brake rub is an issue but not a problem. Most boutique wheels nowadays are not stiff enough to not flex when a powerful rider honks up a hill moving the bike from side to side. This manifests as little scraping noises from where the rim touches the brake. The noise, especially with carbon wheels is amplified and not indicative of the amount of friction it produces. However, this is a special case. Campagnolo acknowledges the problem by fitting single pivot brakes at the rear. Single pivot brakes have a low mechanical advantage and therefore the pads can be far from the rim and the brakes still have enough lever travel to lock the wheel. Some riders on Shimano/SRAM simply open the quick release on the brake a bit to prevent rub in this situation. Nevertheless, wheels with reasonable rims weighing 450 grams or more and 32 or more spokes do not rub. When the spoke count starts to diminish below 28, then wheel flex and consequently wheel rub become noticeable. Lateral wheel flex is not significantly reduced by stronger rims and stronger rims cannot compensate for fewer spokes. It is best dealt with by more and thicker spokes.

Claimed stiffness is almost always based on hearsay – what the magazines tell us repeatedly without any meaningful analysis. Stiff enough is stiff enough.

*Rotating weight. *The holy grail of bicycle wheels. The age old story is that losing weight on a wheel is twice as beneficial as losing weight elsewhere on the bike. Often called rotating weight, it is hailed as the solution to any wheel question. Whist it is based on science, it is not based on reality and the context is never stated. The irony is also never pointed out: rotating weight goes up as the rim profile increases.

Nevertheless, let’s look at the facts of “rotating weight.” We’re really talking of the moment of inertia (MOI) of rotating masses, in this case wheels. It isn’t easy to calculate the MOI for something as complex as a bicycle wheel because we have to mathematically define the transition from hub to tyre and where the mass is located. A rotating cylinder is easier to work with because it has zero mass on the inside and it is all concentrated on the outside at a known radius. Nevertheless, I’ll try and build a model to explain how it works.

There are a few concepts you have to understand about an accelerating bicycle. The first is an understanding of just how weak our engines are. For a bicycle to accelerate from zero to 30 kph is a lengthy struggle. Go and try it on your next ride and see how long it takes you. We accelerate inherently slowly.

Secondly, when we accelerate, we’re accelerating two bodies: 1) The bicycle and rider and pay load in a linear direction and; 2) The wheel in rotation. We are not only accelerating a wheel, like in a salad spinner. We are accelerating a heavy body and a light wheel. Very light, as a percentage of overall mass of the entire body.

Thirdly: We don’t really accelerate when riding a bike. Even so-called “surges” are slow affairs and few and far between. I can prove this. Those of you who do interval training and ride tactically know that you can shake of 90% of the wheelsuckers within the first 5 km of the race by simply surging for 5 or six times as you turn a corner. Half a dozen surges is the total capacity of most average riders, then they drop off. Just by doing a bit of interval training you can already shake off your competition. That’s before even training to ride faster! The accelerations and oft-called micro-acceleration we experience during rides are always over stated. We dont’ ride like that and we can’t accelerate like salad spinners.

I’ll use one method to demonstrate the negligent power requirements of accelerating a wheel over a heavy body. Some of you may come up with different models and we can play with these.

Here I want to to substantiate y argument that a reasonable weight saving of say 200 grams per wheel is no more important than a similar weight saving on the bicycle and rider combo. In other words, stop chasing the holy grail.

In order to avoid semantics, my term “no more important” means that the energy-saving in accelerating the two differently equipped bodies (but with same overall weight) is negligible compared to the total energy input to get those two bodies up to the same speed.

From now on I shall refer to the package of bike and rider simply as “the bike*”. Bike A has the heavier wheels.*

I assume that 200 grams per wheel is reasonable, but if not, we can simply plug in another figure. I weighed a naked rim and tyre, but did not include a tube. Since both wheels need tubes, it will simply cancel out in anyway.

I start off by stating that the total energy stored in a bike travelling at speed is equal to its linear kinetic energy plus its rotational kinetic energy (the energy stored in its spinning wheels).

And by looking at the bike's total stored energy at the end of a constantly-accelerating run, we know how much energy was put in. The one who requires the least energy to get there wins.

The total package’s linear energy is calculated thus: 1/2 M*V^2.

The wheel’s rotational energy is also 1/2M*V^2. We have to add these to get the total.

Assumptions:


The bike weighs 90kgs.


We measure the energy at 30 kph.


The heavy wheel weighs 800 grams.


The light wheel weighs 600 grams.


The bike has two wheels.


All the wheel’s weight is concentrated in the rim/tyre combo.
The hubs and spokes weigh nothing. – but don’t break your head on these two statements, they simply take a bunch of calculations out of the equation that would have cancelled each other in anyway.

The two bikes reached 30 kph under exactly the same conditions in terms of wind, road, gradient etc.

I’m not converting to standard units since we’re only after a ratio. I do the same for both bikes and the effect is therefore nil.

Now for Bike A’s total kinetic energy at say 30 kph.

We know that it is 1/2 MV*^2 (one half mvsquared)

Plus 1/2 M*V^2. for wheels only.

Thus

1/2 x 90 x 30squared Plus 1/2 x 1.6 x 30squared

= 40 500 units Plus 720

*= 41220. units of energy*


Bike B’s total kinetic energy at 30 kph.

1/2 x 90 x 30squared Plus 1/2 x 1.2 x 30squared

= 40500 Plus 540

*= 41040 Units of energy. *


The summary:


***************************************************************************************************************


Bike A has *41220* units of energy stored after an acceleration from 0 to 30kph and

Bike B has *41040* units of energy stored after an acceleration from 0 to 30 kph.

The difference is 180 units of energy or 0,43 percent and that for an all-out acceleration from zero to 30kph.

*Conclusion*: it requires 0,4 percent *less *energy to accelerate a bike with tyres weighing 400 grams less than a bike of equal weight but with heavier tyres.

Wheel upgrades for the usual reasons stated (drag, weight etc) are a waste of money.

Bigger benefits can be found elsewhere such as from training, aerodynamic positioning, nutrition etc.

Amateurs and commuters don’t need racing wheels.


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## Cuchilo (8 Feb 2015)

BOOOOOOOOOOOOOOOOOOORINGGGGGGGGGGGGGGG 
Go for some 40mm carbons . Best of both worlds .



and girls will like you .


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## jowwy (8 Feb 2015)

Yellow Saddle said:


> Of all the scientific or pseudo/marketing scientific issues that divide cyclists, wheels must be right there at the top.
> 
> The story usually goes like this:
> 
> ...


That must be the longest copy and paste of drivel i have ever seen


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## Citius (8 Feb 2015)

jowwy said:


> That must be the longest copy and paste of drivel i have ever seen



Why is it 'drivel'..? I can't do the physics, but the logic of what Yellow Saddle is saying seems pretty reasonable to me.


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## jowwy (8 Feb 2015)

Citius said:


> Why is it 'drivel'..? I can't do the physics, but the logic of what Yellow Saddle is saying seems pretty reasonable to me.


Do you honestly think yellow said any of what was written - i think not

Its marketing hype, blinding people with science to try and get you to buy better wheels. Some of it maybe right, but how do you prove it


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## Citius (8 Feb 2015)

jowwy said:


> Do you honestly think yellow said any of what was written - i think not



It's quite possible he did write it.



jowwy said:


> Its marketing hype, blinding people with science to try and get you to buy better wheels. Some of it maybe right, but how do you prove it



Well, the physics is there for you to disagree with, I suppose. But if you are agreeing that it IS marketing hype, then you are agreeing with Yellow Saddle, are you not?


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## Yellow Saddle (8 Feb 2015)

Citius said:


> But if you are agreeing that it IS marketing hype, then you are agreeing with Yellow Saddle, are you not?




I think you just caught him out there, however I doubt the irony of his statement will ever sink in.


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## Citius (8 Feb 2015)

It did seem to be at odds with his earlier contention of it being 'drivel', which is why I raised it. 

Also, the issue of 'plagiarism' can be solved easily enough. Simply copy a block of the 'offending' text written above - and then run it through google. If google gets any hits on it with links other than to this site, then there's your answer. It should take someone about 30 seconds to establish that it is not plagiarised.


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## midlife (8 Feb 2015)

Who remembers moving to sprints and tubs from 27*1/4 HP wheels.

Seemed to make a huge difference to my TT times 

Shaun


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## Yellow Saddle (8 Feb 2015)

Citius said:


> It did seem to be at odds with his earlier contention of it being 'drivel', which is why I raised it.
> 
> Also, the issue of 'plagiarism' can be solved easily enough. Simply copy a block of the 'offending' text written above - and then run it through google. If google gets any hits on it with links other than to this site, then there's your answer. It should take someone about 30 seconds to establish that it is not plagiarised.


There are even more sophisticated online plagiarism tools which are used at university. They work like a charm.


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## Hacienda71 (8 Feb 2015)

I have recently added a set of 50mm carbon clinchers to my collection of wheels. My deepest previous were only 30mm. I did a bit of research and came to the conclusion a wider more rounded profile should be better in crosswinds. Being a bit of a looney I decided to go out in a 25mph crosswind. They performed fine. As to their speed they seem fast but I will reserve judgement until I find out if my average TT times improve and if my hill climb times change much.


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## Citius (8 Feb 2015)

Hacienda71 said:


> I have recently added a set of 50mm carbon clinchers to my collection of wheels. My deepest previous were only 30mm. I did a bit of research and came to the conclusion a wider more rounded profile should be better in crosswinds. Being a bit of a looney I decided to go out in a 25mph crosswind. They performed fine. As to their speed they seem fast but I will reserve judgement until I find out if my average TT times improve and if my hill climb times change much.



Your hill climb times may or may not change much - depending on what wheels you are replacing, how much they weighed compared to the new set, the tyres you are using and (this is the important bit) whether your fitness - or more specifically your w/kg - has improved in the interim. Lots of variables there, so good luck in attributing any improvement to the wheels alone.


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## Hacienda71 (8 Feb 2015)

I suppose I could run the different wheelsets repeatedly over the same mile stretch of road on the same day with a power meter on, but tbh I ain't that anal.


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## Yellow Saddle (8 Feb 2015)

Hacienda71 said:


> I suppose I could run the different wheelsets repeatedly over the same mile stretch of road on the same day with a power meter on, but tbh I ain't that anal.


That would hardly constitute a reliable experiment. Too many variables and no controls.


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## Hacienda71 (8 Feb 2015)

Yellow Saddle said:


> That would hardly constitute a reliable experiment. Too many variables and no controls.


What I need to be more anal than that. Definitely can't be arsed. I'll stick to just riding my bike.


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## Arrowfoot (8 Feb 2015)

jowwy said:


> Do you honestly think yellow said any of what was written - i think not
> 
> Its marketing hype, blinding people with science to try and get you to buy better wheels. Some of it maybe right, but how do you prove it



Its the way around. He is actually telling you not to waste money buying more expensive wheels. I have yet to see a scientific rebuttal to what what was posted.


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## jdtate101 (8 Feb 2015)

When looking at race wheels I decided on a compromise too. 40mm full carbon's instead of 50mm+. I know that's not a huge difference but they're lighter than your avg deep sections (1545g) and less prone to side wind, yet give some aero benefit. The main reason why I went for them (Mavic Cosmic Carbone 40C) was the £1 for 2yr crash replacement policy (Mavic's MP3), so i'm protected if I bin them. I also went for them so I can use them on Alpine trips without worrying about brake track heat too much. Yes they are expensive, but that £1 peace of mind was well worth it IMHO. That £1 deal was a special offer at the time of purchase...it's now around £140 for 2 yrs cover.


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## oldroadman (9 Feb 2015)

First point, are the wheels you have been persuaded you "need" by marketeers actually UCI/BC legal. Check the rules by the book or online. Some deep sections are not allowed. Second, the benefit is often in the mind. How much difference will it make when in a peloton? Learn to get in correct positions and shelter properly and about 30% energy is saved, far more than any wheel can achieve. Third, crosswinds, see second, in a good position in an echelon aero helps a bit but also may compromise control. Fourth, you don't say what standard you are at, at the top end pros use aero kit to get the last squeeze of performance from an already high wattage. Watching the races in UK, I see plenty of people going out of the back with very nice kit that is expensive, when they could have gone out of the back with much less expensive stuff. A good coach and training plan will produce far more than fancy wheels. Once at the absolute top of ability, then use every other legal advantage, until then save your money!
What happens in a team is that the equipment is issued, and you just get on with it, as it tends to be good anyway. Only for TTs does the really fancy stuff get used, and then only for a selected few who have a chance of a high level performance.
Summary: Training, coach, race lots, improve, then consider whether expensive wheels will make much difference, once the level of "marginal gains" has been reached.
Then again, if you just fancy posh kit and can afford it, enjoy - but it won't make that much difference!


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## jack smith (9 Feb 2015)

Just go with 100mm front and rear lol! Or double discs if its allowed.. Bugger the science!


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## oldroadman (9 Feb 2015)

jack smith said:


> Just go with 100mm front and rear lol! Or double discs if its allowed.. Bugger the science!


Check the regulations first. I'm pretty sure extra deep (100mm) is not allowed in road racing, and discs certainly not. If you really want cross wind carnage, of course....


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## Citius (9 Feb 2015)

BC rules are minimum 16 spokes - so no solid disks outside of certain track events. I don't think there is a BC guideline on rim depth. Riders regularly turn up to races with Zipp 808, PX 101 or similar, although I personally wouldn't want to be riding next to someone with those, on a windy day.


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## jack smith (9 Feb 2015)

Wow I was joking!


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## Pumpkin the robot (10 Feb 2015)

If (and it is a big if) a heavier rim slows you on acceleration, surley the added weight would mean you do not lose speed once you had accelerated as it is acting as a heavier flywheel? So what you give with one hand you take with the other?


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## Yellow Saddle (10 Feb 2015)

Martin Archer said:


> If (and it is a big if) a heavier rim slows you on acceleration, surley the added weight would mean you do not lose speed once you had accelerated as it is acting as a heavier flywheel? So what you give with one hand you take with the other?


Exactly, The energy required to accelerate the heavier wheel up to speed is not wasted, but stored in the wheel for later use. A bit like the tyre I carry around my waste...for later use.


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## Citius (10 Feb 2015)

Yellow Saddle said:


> Exactly, The energy required to accelerate the heavier wheel up to speed is not wasted, but stored in the wheel for later use. A bit like the tyre I carry around my waste...for later use.



The energy used to accelerate the heavier wheel is returned in the form of slower deceleration - the opposite is true for a lighter wheel - so the net result is about the same. The differences are still relatively minor though.


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## Yellow Saddle (10 Feb 2015)

Citius said:


> The energy used to accelerate the heavier wheel is returned in the form of slower deceleration - the opposite is true for a lighter wheel - so the net result is about the same. The differences are still relatively minor though.


The equation in my argument puts "relatively minor" in perspective. I once surreptitiously filled a friend's tyres with water and after several rides I let the cat out the bag. He never noticed the 3kgs of extra weight in his wheels, yet he was convinced his one set of wheels were more "responsive" than the other.


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## Spoked Wheels (10 Feb 2015)

Yellow Saddle said:


> The equation in my argument puts "relatively minor" in perspective. I once surreptitiously filled a friend's tyres with water and after several rides I let the cat out the bag. He never noticed the 3kgs of extra weight in his wheels, yet he was convinced his one set of wheels were more "responsive" than the other.


Maybe not on the flat but you would notice 3kg climbing. I lost 3kg in body weight and fell the benefit when climbing. I couldn't notice much difference on the flat though, perhaps I could have gone faster. There is a hill that is steep and hard (for me at least  ) not very long but before I lost the 3kg I would run out gears and struggle the last 25 or 30 metres. Since then I've lost more weight and I even have gears to spare but I'm not saying how many


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## montage (12 Feb 2015)

Martin Archer said:


> If (and it is a big if) a heavier rim slows you on acceleration, surley the added weight would mean you do not lose speed once you had accelerated as it is acting as a heavier flywheel? So what you give with one hand you take with the other?



Whilst the logic is understandable - If you are purposely decelerating whilst racing, the weight of your wheels is the least of your concerns


Conservation of momentum - theoretically take a 7kg bike, one has 1kg wheels and a 6kg frame etc, the other has 2kg wheels and a 5kg frame etc. Test these in lab conditions, by putting in X amount of power for X amount of time and measuring the speed and distance traveled, and the lighter wheels will accelerate quicker than the heavier wheels, but will decelerate quicker than the heavier wheels. The result - no loss of energy overall, the speed and distance covered for both wheels should be identical.

In reality, the deceleration component of the equation is pretty much removed, due to the factor of braking round corners etc. If we think about the process of cornering fast, this becomes obvious - you ride hard until the last possible moment, brake before the corner, freewheel round, then accelerate out of it. The deceleration process is more or less eliminated, rendering the advantage of heavier wheels (slower to decelerate due to conservation of momentum) non existent. Assuming two identical riders with the above bikes, putting out the same power at the same time, the rider with the lighter wheels will go through the cornering process quicker - add this up over a crit or road race course and the results are obvious.


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## montage (12 Feb 2015)

Yellow Saddle said:


> Exactly, The energy required to accelerate the heavier wheel up to speed is not wasted, but stored in the wheel for later use. A bit like the tyre I carry around my waste...for later use.



As above - that stored energy dissipates the moment you hit the brakes.


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## Pumpkin the robot (12 Feb 2015)

What about the stored energy when you are on the flat? A heavier wheel will not require as much energy to keep it going when it is at speed.
You can make any scenario and use figures to prove a point, but at the end of the day it is not lab conditions and it is virtually impossible to measure every detail that could make a difference. I had a discussion with someone that was involved with the design of racing car engines and we were discussing flywheel weights and he told most people make the flt wheel lighter as it spins up quickly, but when it is heavier it wants to keep spinning so you do not lose momentum and that helps keep the revs up. It wasnt as straight forward as that, as
the weight and diameter of the wheel make a difference.


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## Citius (12 Feb 2015)

Martin Archer said:


> What about the stored energy when you are on the flat?



All I would say is the angle of the road doesn't change the underlying physics.


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## Pumpkin the robot (12 Feb 2015)

Does the centrifugal force of the wheel not make a difference?


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## Citius (12 Feb 2015)

sorry, I don't know what you mean. Assuming you mean centripetal force, how would the angle of the road alter that?


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## oldroadman (13 Feb 2015)

Lots of lovely theory. Meanwhile, in the real world, roads tend to go up and down a bit. Light wheels make climbing easier (relative term!), and as the majority of people are not particularly skilled descenders, "stored energy" is a pointless concept as braking (generates heat=energy) will convert it and it won't be available to the rider. When it does work is on indoor tracks, which is why disc wheels (quite heavy) are effective as they are aero and riding a fixed gear helps to ensure a smooth ride where the rotational mass helps. Not for nothing are any form of additional weights banned in disc wheels.
All I know from a bit of experience is this - light wheels work best, and all the stored energy theory is nonsense from the instant you brake, which is what happens in road races when you go round corners, descend, slow to avoid the fallen, etc.


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## Citius (13 Feb 2015)

The term 'stored energy' is misleading, I think. But the principle that a heavier wheel requires a higher force to accelerate it - an input which is then returned in the form of slower deceleration, is an actual law of physics.


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## derrick (13 Feb 2015)

I have just started using a set of cosmic carbone sle : wheels 2190 grams with tyres and tubes,have done 80 miles on them, previously i used Mavic Ksyrium Elite 2060 grams with tyres and tubes. It's really hard to notice a lot of difference climbing feels exactly the same, i do feel the aero wheels have an edge on the flat, but how can one be sure, as for the cross winds the aero wheels actually feel better all though the cross winds i have ridden in have been very light, so the jury is still out on that one. will know more when i start riding with people i know, there are a few of us are evenly matched but even then we all have bad days and good days, so who knows, One thing i do know is they look the b******s, So the feel good factor comes into play here. that always makes you faster, So if you like them and can afford them go for it.


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## adscrim (13 Feb 2015)

derrick said:


> One thing i do know is they look the b******s, So the feel good factor comes into play here. that always makes you faster, So if you like them and can afford them go for it.


Amen!


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## oldroadman (13 Feb 2015)

Citius said:


> The term 'stored energy' is misleading, I think. But the principle that a heavier wheel requires a higher force to accelerate it - an input which is then returned in the form of slower deceleration, is an actual law of physics.


Which is true, however we generally don't slow down gently to preserve momentum, braking occurs, and the "stored energy" gets used up as heat. Thus the law of physics which states that energy remains at a given constant level, but in different forms, friction generating heat in various quantities being a good example, via braking, bearing resistance and of course aerodynamic causes.


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## Citius (13 Feb 2015)

Unless you maintain a perfectly circular pedal technique where a constant force is maintained throughout the pedal stroke (which nobody does, regardless of what they might claim) - then the wheel will begin to decelerate every time you ease off the pressure. In other words, unless you are actively accelerating the wheel, it will be decelerating, regardless of whether you are braking or not. 

The exception is obviously when going down hill - but that's a different law of physics


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## Cyclist33 (13 Feb 2015)

i would just like to note for the record in response to the long post by y saddle that i was misquoted as i didnt say in another thread that a pair of my wheels was both stiff and compliant, as is stated. i did say they were stiff and comfortable, which i do not see as mutually exclusive terms, indeed in general terms i find myself more comfortable on a bike the less it lolls spongily .


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## Cyclist33 (13 Feb 2015)

and i should also note that not everything in life must be quantifiable to be valid or valuable empirical evidence. qualitative evidence is of equal value as are the opinions of fellow beings. sadly this is not a view shared by everyone, particularly the conventional and unimaginative science type, of which there are disappointingly many these days!


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## Citius (13 Feb 2015)

Cyclist33 said:


> and i should also note that not everything in life must be quantifiable to be valid or valuable empirical evidence. qualitative evidence is of equal value as are the opinions of fellow beings. sadly this is not a view shared by everyone, particularly the conventional and unimaginative science type, of which there are disappointingly many these days!



That may be true - but believing that certain types of wheels make you faster is not the same as being able to prove it. Which is why science can sometimes be the only reliable fall-back when the inevitable disagreement comes.


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## Cyclist33 (13 Feb 2015)

btw did you mean 0.4 % less energy to accelerate lighter wheeled bike?

great post btw, just not the whole story!




Yellow Saddle said:


> I think you just caught him out there, however I doubt the irony of his statement will ever sink in.[/QUOTE


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## Cyclist33 (13 Feb 2015)

Citius said:


> That may be true - but believing that certain types of wheels make you faster is not the same as being able to prove it. Which is why science can sometimes be the only reliable fall-back when the inevitable disagreement comes.



yes but being able to prove it is not that important either if youre not trying to, ie if youre not bound by the need to prove that science is RIGHT it doesnt matter if it is or isnt.


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## Citius (13 Feb 2015)

Obviously if you're not trying to prove anything, then threads like this should be of no interest. For instance, I'm sure there are still people around who believe the earth is flat, because they don't know any better.


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## Cyclist33 (13 Feb 2015)

Citius said:


> Obviously if you're not trying to prove anything, then threads like this should be of no interest. For instance, I'm sure there are still people around who believe the earth is flat, because they don't know any better.



the Earth IS flat if you live in cheshire.

but seriously, i hope youre not suggesting that a thread may only be interesting and or contributed to if the putative contributor can and wishes to prove scientifically their point? wouldnt be much of a forum if so. i use the term scientifically in its conventional sense because everybody knows that qualitative information and opinion make the world go round as surely as physics. you'd hope.

the existence value and feelgood factor of new wheels and their contribution to the biodiversity of aesthetic tastes justifies selection and purchase of new wheels as surely as any physical modelling does, as far as im concerned. it also helps the economy and supports green transport and promotes cycling in general.


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## Yellow Saddle (13 Feb 2015)

Cyclist33 said:


> the Earth IS flat if you live in cheshire.
> 
> cut cut cut cut cut cut
> 
> the existence value and feelgood factor of new wheels and their contribution to the biodiversity of aesthetic tastes justifies selection and purchase of new wheels as surely as any physical modelling does, as far as im concerned. it also helps the economy and supports green transport and promotes cycling in general.



I never denied that, in fact in another thread an OP and I agreed that he should get fancier wheels 'cause he thought they were very pretty or some such. I have no argument nor beef against that. This post started off because a beginner asked for advice and he was given the normal story about lighter wheels, deep section etc when he definitely could do better without them. Then the argument started.

As for your take on stiff and comfortable and my translation of comfort as compliance, I don't see were you find the inaccuracy in my use of "compliance". Comfort can only come from compliance, nothing else (assuming that the wheel is actually round). But perhaps you have other sources for comfort in wheels?


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## Cuchilo (14 Feb 2015)

So what are the best wheels to get again ?


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## T.M.H.N.E.T (14 Feb 2015)

Cuchilo said:


> So what are the best wheels to get again ?


Square ones


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## Joshua Plumtree (14 Feb 2015)

Cuchilo said:


> So what are the best wheels to get again ?



I suppose I must be really dumb, but, as far as I can tell, this thread appears to suggest that cheaper heavier wheels are faster.


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## Citius (14 Feb 2015)

Joshua Plumtree said:


> I suppose I must be really dumb, but, as far as I can tell, this thread appears to suggest that cheaper heavier wheels are faster.



That's quite an impressive, wholesale misunderstanding of the thread content, if that's what you really think. I'm hoping not.


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## Cuchilo (14 Feb 2015)

Citius said:


> That's quite an impressive, wholesale misunderstanding of the thread content, if that's what you really think. I'm hoping not.


You give yourself far too much credit


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## Rob3rt (15 Feb 2015)

Yellow Saddle said:


> That would hardly constitute a reliable experiment. Too many variables and no controls.



Depends how you go about it...


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## Yellow Saddle (15 Feb 2015)

Rob3rt said:


> Depends how you go about it...


Well, that's obvious, innit?

To create a reliable experiment you would remove the variables and include controls. But perhaps you have a different suggestion?


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## montage (20 Feb 2015)

T.M.H.N.E.T said:


> Square ones



Wheels don't actually _have_ to be circular....


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## Yellow Saddle (21 Feb 2015)

montage said:


> Wheels don't actually _have_ to be circular....




Yes, but then the hub has to precess.


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## Spoked Wheels (26 Feb 2015)

Citius said:


> the issue of 'plagiarism' can be solved easily enough. Simply copy a block of the 'offending' text written above - and then run it through google. If google gets any hits on it with links other than to this site, then there's your answer.



That is what I call an exact science


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## Spoked Wheels (26 Feb 2015)

Cuchilo said:


> So what are the best wheels to get again ?



I think it is safe to say "round wheels"


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## Citius (26 Feb 2015)

Spoked Wheels said:


> That is what I call an exact science



Nobody claimed it was an exact science, but that's basically (simplistically) how plagiarism checkers work. How else would you do it?


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## Spoked Wheels (26 Feb 2015)

@Citius Sorry, I was just been a bit sarcastic and jumped at the chance to have a bit of fun 

A search engine like google is probably one of the techniques they use but there are others for sure to deal with so much written work that hasn't made it to the net yet. For example, I have my dissertation in digital format but I have never published it on the Internet, you would need other means to prove plagiarism. 

In all honesty when you look at the post in question, with all the text formatting and so on, it does look like a cut and paste job, however, I do believe yellow saddle is not copying somebody else's work At a guess, and knowing he is an author, he probably quotes his own work.


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## Yellow Saddle (26 Feb 2015)

Spoked Wheels said:


> @Citius Sorry, I was just been a bit sarcastic and jumped at the chance to have a bit of fun
> 
> A search engine like google is probably one of the techniques they use but there are others for sure to deal with so much written work that hasn't made it to the net yet. For example, I have my dissertation in digital format but I have never published it on the Internet, you would need other means to prove plagiarism.
> 
> In all honesty when you look at the post in question, with all the text formatting and so on, it does look like a cut and paste job, however, I do believe yellow saddle is not copying somebody else's work At a guess, and knowing he is an author, he probably quotes his own work.



Yup, that's how I do it. I have a large electronic archive here of unpublished dissertations by deceased people who can't raise the flag. I just cut and paste appropriate bits and pieces, but sometimes I just make stuff up as well. The latter is entirely my own work.


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## Citius (26 Feb 2015)

Trouble is, the accusations of plagiarism seem to be from people who would rather attack the poster, rather than the points he is making. Probably because the points he makes are accurate..


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## Spoked Wheels (26 Feb 2015)

Citius said:


> Trouble is, the accusations of plagiarism seem to be from people who would rather attack the poster, rather than the points he is making. Probably because the points he makes are accurate..



I don't have a problem with his views as I agree with most of them but I do get a bit jumpy sometimes with the way he puts his poins acrross  must be the Latin blood in me.


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## Yellow Saddle (26 Feb 2015)

Spoked Wheels said:


> I don't have a problem with his views as I agree with most of them but I do get a bit jumpy sometimes with the way he puts his poins acrross  must be the Latin blood in me.


Or the fact that he communicates in his second language and sometimes completely overlooks the nuances.


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## Citius (26 Feb 2015)

I can barely communicate in my first language - wouldn't fancy trying it in a foreign tongue.


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## smutchin (27 Feb 2015)

Yellow Saddle said:


> Comfort can only come from compliance, nothing else (assuming that the wheel is actually round). But perhaps you have other sources for comfort in wheels?



The phrase I still enjoy no matter how many times I hear it is "lateral stiffness and vertical compliance". 

I suppose any vertical compliance in wheels would have to be provided by the tyres rather than the wheels themselves.

Although it's hard to see how you could quantify how much comfort is provided by the wheels in isolation - comfort on a bike is surely a function of the overall package, and I suspect fit is at least as important as the bike's ability to absorb/deflect bumps.


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## Yellow Saddle (27 Feb 2015)

smutchin said:


> The phrase I still enjoy no matter how many times I hear it is "lateral stiffness and vertical compliance".
> 
> I suppose any vertical compliance in wheels would have to be provided by the tyres rather than the wheels themselves.
> 
> Although it's hard to see how you could quantify how much comfort is provided by the wheels in isolation - comfort on a bike is surely a function of the overall package, and I suspect fit is at least as important as the bike's ability to absorb/deflect bumps.


The irony of it all is that it is actually the other way around. Wheels are laterally compliant and vertically stiff.
With a modest amount of push on a wheel held like a steering wheel and pushed on the axle resting on a block of wood, you can easily make it bend 30mm. However, with a rider's weight on the bike, the wheel squashes in by less than 0.5mm (no tyre fitted). We all know that tyres are far more compliant than that Yet, bike magazine hacks claim they can "feel" the compliance in the wheel. And then paradoxically tell us that when they apply the power, the wheel doesn't argue and just shoots forward.

Product label science should best not be copied and repackaged as journalism.


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## smutchin (27 Feb 2015)

Yellow Saddle said:


> bike magazine hacks claim they can "feel" the compliance in the wheel. And then paradoxically tell us that when they apply the power, the wheel doesn't argue and just shoots forward.



Is that a scientifically tested statement?

I just checked over the last two wheel group tests we published and there's no such claim made in either - lots of talk of stiffness vs [lateral] flex, but no claims of 'vertical compliance' (only mentions of comfort are in relation to rim width and how it affects tyre profile) and certainly no claim that any wheel offers both compliance _and_ stiffness. Maybe you're talking about inferior bike magazine hacks to the ones I work with.


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## Yellow Saddle (27 Feb 2015)

smutchin said:


> Is that a scientifically tested statement?
> 
> I just checked over the last two wheel group tests we published and there's no such claim made in either - lots of talk of stiffness vs [lateral] flex, but no claims of 'vertical compliance' (only mentions of comfort are in relation to rim width and how it affects tyre profile) and certainly no claim that any wheel offers both compliance _and_ stiffness. Maybe you're talking about inferior bike magazine hacks to the ones I work with.


Which one do you work with? If you don't want to tell me in public, that's OK. Send me some product reviews from that mag and I'll point out the equivalent statements to the stupidity under discussion.


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## smutchin (27 Feb 2015)

Yellow Saddle said:


> Send me some product reviews from that mag and I'll point out the equivalent statements to the stupidity under discussion.



Ha. Good one.

No, I'm asking if you can provide a citation for the specific form of stupidity you mentioned. If it's is a genuine example, I'm genuinely interested to know where you've read it. 

The trouble is, you say stuff like that and because you have the air of scientific authority it gets accepted as fact. If you want to cite examples of stupidity, why not use real ones? There are plenty out there, so no need to invent spurious examples.

In the context of a discussion of scientific principles, it pays to be accurate.


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## Yellow Saddle (27 Feb 2015)

smutchin said:


> Ha. Good one.
> 
> No, I'm asking if you can provide a citation for the specific form of stupidity you mentioned. If it's is a genuine example, I'm genuinely interested to know where you've read it.
> 
> ...


Got it. So far I've just quoted from memory and license, but I'll find you some howlers.


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## Yellow Saddle (27 Feb 2015)

smutchin said:


> Ha. Good one.
> 
> No, I'm asking if you can provide a citation for the specific form of stupidity you mentioned. If it's is a genuine example, I'm genuinely interested to know where you've read it.
> 
> ...


Why not shop local? I found quite a few right here:

https://www.cyclechat.net/threads/campagnolo-zonda-clincher-wheelset.154613/
I only scanned the first two pages and there as some beauts there.


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## smutchin (27 Feb 2015)

Yellow Saddle said:


> So far I've just quoted from memory and license



You might get away with that on a cycling forum but I hope your editor doesn't allow you to be so slapdash in your books.


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## smutchin (27 Feb 2015)

Yellow Saddle said:


> Why not shop local?



To clarify: I'm asking specifically where you have read in a bike magazine a claim that a wheel is both vertically compliant and stiff.

But you've already admitted that you made up the example anyway so don't worry about it.


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## Spoked Wheels (27 Feb 2015)

Yellow Saddle said:


> The irony of it all is that it is actually the other way around. Wheels are laterally compliant and vertically stiff.
> _*With a modest amount of push on a wheel held like a steering wheel and pushed on the axle resting on a block of wood, you can easily make it bend 30mm*_. However, with a rider's weight on the bike, the wheel squashes in by less than 0.5mm (no tyre fitted). We all know that tyres are far more compliant than that Yet, bike magazine hacks claim they can "feel" the compliance in the wheel. And then paradoxically tell us that when they apply the power, the wheel doesn't argue and just shoots forward.
> 
> Product label science should best not be copied and repackaged as journalism.



You wouldn't even get 10mm with the wheels I have been building lately  I'm not joking..... I'll put my neck on the line here and say ask @Soltydog or @w00hoo_kent to do the test you described above and if they get anywhere 30mm without actually breaking the wheel I'll pay you £100 but if they can't then you pay me £100, how is that? . I'm certainly not strong enough to get 10mm, maybe a machine can do that but I would not classify that as a modest amount of push.


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## Pedrosanchezo (27 Feb 2015)

Wow, that is a lot of pages! I was interested to see what the initial feedback was from the Op's question, but i get the feeling that not everyone agrees. ;-)

Bike weight makes a difference to performance (try racing on your 11kg winter bike!). So one can assume wheel weight makes a difference as part of the bikes overall 
weight. 
The faster a rider travels the more air resistance he or she is going to encounter. Most races are on the faster end of the general cycling scale. Aero trumps weight in most cases. 

There are many factors to consider in picking your wheel but in general one might concern themselves with material, width, depth, spoke count, warranty and build process - ie hand built or factory. All of these make a difference in terms of performance and feel. All of this is quantifiable. Obviously imo. 

"Get a coach" is good advice if you are in a position to do so. Do as you are told and follow a pretty strict program. If you are just fancying giving racing a go and also fancy the idea of some new wheels then perhaps "getting a coach" isn't the best advice available. 

Finally i would add that if anyone is suggesting that a £100 pair of 15mm deep 2 kilogram wheels with gatorskins offer the OP the same performance as a pair of wheelsmith tubs (38mm - 1200 grams) or (38mm clinchers - 1400 grams) with quality tyres, then i'd suggest trying the two wheel sets out over a set distance and seeing the difference. Same goes for 50mm versions. I have a power meter and good wheels and shitty wheels, shitty tyres too, and i can freely tell you that a significant gain or loss can be had by choosing certain tyre and wheel combinations. Position on bike makes a huge difference too. 

Perhaps get new wheels and a coach. ;-)


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## Citius (27 Feb 2015)

Pedrosanchezo said:


> Bike weight makes a difference to performance (try racing on your 11kg winter bike!). So one can assume wheel weight makes a difference as part of the bikes overallweight.
> The faster a rider travels the more air resistance he or she is going to encounter. Most races are on the faster end of the general cycling scale. Aero trumps weight in most cases.



Assuming by 'aero' you mean the overall combination of bike and rider, then aero does indeed trump weight on the flat. But weight trumps aero uphill. That's why there is no easy answer. 

All I would add is that something cannot be 'quanfiable in your opinion'. It either is quantifiable (in which case, quantify it) or it isn't.


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## Soltydog (27 Feb 2015)

Spoked Wheels said:


> You wouldn't even get 10mm with the wheels I have been building lately  I'm not joking..... I'll put my neck on the line here and say ask @Soltydog or @w00hoo_kent to do the test you described above and if they get anywhere 30mm without actually breaking the wheel I'll pay you £100 but if they can't then you pay me £100, how is that? . I'm certainly not strong enough to get 10mm, maybe a machine can do that but I would not classify that as a modest amount of push.



I'm not sure I'd want to try it, but I think @Spoked Wheels is right, no way will my wheels bend 30mm & I wouldn't like to even try for 10mm 
Even my 'cheap' previous wheels FSA RD-60 would be hard pushed to have 30mm movement without breaking, but I may be proved to be wrong  they do rub on the brakes when I'm standing up & pushing hard on the pedals, but that would only need a few mm of movement. If a wheel ha 30mm of 'flex' in it, surely it would feel like riding on cheese??? or am i missing something?


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## smutchin (28 Feb 2015)

Just guessing, but I imagine you'd get a bit more flex by deliberately pressing down on the rim than you would under normal riding conditions.

You could, I suppose, measure wheel stiffness objectively by suspending the wheel by the hub and hanging weights off the rim then measuring the deflection. I wonder how much force you would actually need to get 30mm flex.


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## Yellow Saddle (28 Feb 2015)

30mm is just a thumbsuck based on a 24h Shimano 29" MTB wheel that rubbed the paint off the inside of his suspension fork. The customer couldn't explain the rub marks but upon investigation we discovered that the wheel easily flexed the (estimated) 30mm. What the customer found strange was that the wheel touched the one side only. But that's explained by the wheel's dish. It was a disc brake wheel. That's the worst case I've ever encountered but don't take the 30mm as gospel. I don't have a representative bike here to re-look at the distance.


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## Pedrosanchezo (28 Feb 2015)

Citius said:


> Assuming by 'aero' you mean the overall combination of bike and rider, then aero does indeed trump weight on the flat. But weight trumps aero uphill. That's why there is no easy answer.
> 
> All I would add is that something cannot be 'quanfiable in your opinion'. It either is quantifiable (in which case, quantify it) or it isn't.


It very much is quantifiable and if you google the effect of aero wheels, and perhaps kit, you will see this. Also worth noting that aero still trumps weight up hills if the gradient is not too steep and the speed is adequate. Though plenty of carbon wheels have the benefit of being light weight and aero. 

Here is a quick link to something that might be of interest........

Oh and one could always suggest shaving ones legs too as a new study has proven it to be faster.


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## Citius (1 Mar 2015)

Pedrosanchezo said:


> It very much is quantifiable and if you google the effect of aero wheels, and perhaps kit, you will see this. Also worth noting that aero still trumps weight up hills if the gradient is not too steep and the speed is adequate. Though plenty of carbon wheels have the benefit of being light weight and aero.
> 
> Here is a quick link to something that might be of interest........
> 
> Oh and one could always suggest shaving ones legs too as a new study has proven it to be faster.



The best aero wheels are reckoned to be worth about an extra 0.4mph at a speed of 25mph, and as soon as the speed drops (as it would when you hit an incline, unless you increase your power in response) you begin to rely on KE as well as fighting gravity and weight. Aero wheels will not get you up an incline, no matter how small, without other forces coming into play. So to say that aero still trumps weight uphill is potentially misleading.

That's why people are saying there is no easy answer to this question.


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## Spoked Wheels (1 Mar 2015)

Pedrosanchezo said:


> Also worth noting that aero still trumps weight up hills if the gradient is not too steep and the speed is adequate



Isn't that inertia? That surely last a few meters only.


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## Yellow Saddle (1 Mar 2015)

Spoked Wheels said:


> Isn't that inertia? That surely last a few meters only.


No, he's saying that if you maintain a speed up the hill that's fast enough for reasonable airflow past the wheel, then the advantage of an aerodynamic wheel is bigger than the disadvantage of that wheel being slightly heavier.


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## smutchin (1 Mar 2015)

The chances of me being able to maintain >20mph up any gradient deserving of the name 'hill' for long enough to notice any aero benefit are in the range slim to non-existent.

Mind you, I'm not entirely convinced I'd notice the extra weight either, if it were only a matter of a few hundred grams.


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## Cyclist33 (1 Mar 2015)

Yellow Saddle said:


> 30mm is just a thumbsuck based on a 24h Shimano 29" MTB wheel that rubbed the paint off the inside of his suspension fork. The customer couldn't explain the rub marks but upon investigation we discovered that the wheel easily flexed the (estimated) 30mm. What the customer found strange was that the wheel touched the one side only. But that's explained by the wheel's dish. It was a disc brake wheel. That's the worst case I've ever encountered but don't take the 30mm as gospel. I don't have a representative bike here to re-look at the distance.



can you clarify that a bit plz? on my mtb there is no more than 10mm betwixt the outer edge of the tyre 26x2.1 and the inside surface of the fork... so how could the wheel flex 30mm laterally before the tyre started rubbing the fork?

ta

stu


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## Cyclist33 (1 Mar 2015)

Pedrosanchezo said:


> It very much is quantifiable and if you google the effect of aero wheels, and perhaps kit, you will see this. Also worth noting that aero still trumps weight up hills if the gradient is not too steep and the speed is adequate. Though plenty of carbon wheels have the benefit of being light weight and aero.
> 
> Here is a quick link to something that might be of interest........
> 
> Oh and one could always suggest shaving ones legs too as a new study has proven it to be faster.



i think the point is you listed several things as factors in the "performance and feel" of a ride, and it was the performance and feel that you said were quantifiable. thats how your post reads anyway. whilst the factors may be quantifiable, i think we were hoping you might quantify "feel" because it seems a somewhat qualitative notion to me...


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## Yellow Saddle (1 Mar 2015)

Cyclist33 said:


> can you clarify that a bit plz? on my mtb there is no more than 10mm betwixt the outer edge of the tyre 26x2.1 and the inside surface of the fork... so how could the wheel flex 30mm laterally before the tyre started rubbing the fork?
> 
> ta
> 
> stu


Like I said, don't take it for gospel, If you tell me there is only 10mm there, then so be it.

ta


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## Cyclist33 (1 Mar 2015)

well, i just thought i might be misreading what you meant, because in my experience there arent many front forks that have any more clearance between their inseam and the tyre edge.


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## Yellow Saddle (1 Mar 2015)

Like I said, don't take it for gospel, If you tell me there is only 10mm there, then so be it.

But let me not guess anymore, it is not a mystery.

The OLD of a front wheel is 100mm.
The fork lowers are 40mm each, so in total the two eat into the available gap by 40mm, which leaves us 60mm.

Your tyre is 2.1 inches or 52mm. Which leaves 8mm.

The exact gap per size is 4mm. Waaaaay under my silly thumbsuck.

ta

Edit: I'm getting myself tangled in my own edits here. Sorry.


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## oldroadman (3 Mar 2015)

Yellow Saddle said:


> The irony of it all is that it is actually the other way around. Wheels are laterally compliant and vertically stiff.
> With a modest amount of push on a wheel held like a steering wheel and pushed on the axle resting on a block of wood, you can easily make it bend 30mm. However, with a rider's weight on the bike, the wheel squashes in by less than 0.5mm (no tyre fitted). We all know that tyres are far more compliant than that Yet, bike magazine hacks claim they can "feel" the compliance in the wheel. And then paradoxically tell us that when they apply the power, the wheel doesn't argue and just shoots forward.
> 
> Product label science should best not be copied and repackaged as journalism.


Seems to me a lot of these journos are nowhere near generating enough power to bend a spoon, let alone wheels.


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## oldroadman (3 Mar 2015)

Yellow Saddle said:


> Like I said, don't take it for gospel, If you tell me there is only 10mm there, then so be it.
> 
> But let me not guess anymore, it is not a mystery.
> 
> ...


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## Justinslow (4 Mar 2015)

Yellow Saddle said:


> 30mm is just a thumbsuck based on a 24h Shimano 29" MTB wheel that rubbed the paint off the inside of his suspension fork. The customer couldn't explain the rub marks but upon investigation we discovered that the wheel easily flexed the (estimated) 30mm. What the customer found strange was that the wheel touched the one side only. But that's explained by the wheel's dish. It was a disc brake wheel. That's the worst case I've ever encountered but don't take the 30mm as gospel. I don't have a representative bike here to re-look at the distance.


More like the QR wasn't done up tight enough, under braking the wheel would slew over and possibly touch the fork, ask me how I know this...........


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## oldroadman (5 Mar 2015)

I'm trying to work out what a 29" MTB wheel has to do with road aero wheels? Maybe I misunderstood the clearance bit, because there are no 2.1" wide road tyres? If the forks are getting rubbed, then there's a serious problem, and as disc brakes are nor permitted in road racing, that would eliminate one cause, which just leaves the QR not tightened properly as a likely option. Never a good idea!


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## jowwy (5 Mar 2015)

oldroadman said:


> I'm trying to work out what a 29" MTB wheel has to do with road aero wheels? Maybe I misunderstood the clearance bit, because there are no 2.1" wide road tyres? If the forks are getting rubbed, then there's a serious problem, and as disc brakes are nor permitted in road racing, that would eliminate one cause, which just leaves the QR not tightened properly as a likely option. Never a good idea!


because yellow saddle is trying to justify the nonsense he is spouting out........


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## Yellow Saddle (5 Mar 2015)

oldroadman said:


> I'm trying to work out what a 29" MTB wheel has to do with road aero wheels? Maybe I misunderstood the clearance bit, because there are no 2.1" wide road tyres? If the forks are getting rubbed, then there's a serious problem, and as disc brakes are nor permitted in road racing, that would eliminate one cause, which just leaves the QR not tightened properly as a likely option. Never a good idea!


The discussion veered into wheel flexibility at some stage and I used an example of a flexible wheel I came across, which happened to be MTB wheel, to demonstrate a point.


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## h0lly1991 (6 Mar 2015)

You lot are so funny.... From my warm seat reading this and looking from the outside it doesn't look like some people like being "outed" as a google bunny.
Anyway carry on its become my afternoon reading catching up with this thread.


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## Spoked Wheels (30 Apr 2015)

h0lly1991 said:


> You lot are so funny.... From my warm seat reading this and looking from the outside it doesn't look like some people like being "outed" as a google bunny.
> Anyway carry on its become my afternoon reading catching up with this thread.


Now, why did you have to post that? It ended the thread ...

I haven't done any reseach or study any case but I'm so suspicious of 29" MTB wheels when it comes to flexing. 

Can anybody tell me I have no reason to be suspicious?


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