# Weight! Does it really matter?



## knapdog (24 Oct 2009)

I'm wondering what real difference it makes to our riding when *we *lose weight, put it on or sweat over buying a much lighter bike! We scratch our heads in irritation if we put on a new saddle that may weigh 100g more than the original, or smile with glee about saving a few grams in weight for carbon pedals. Perhaps, I shouldn't have had that extra sausage for breakfast as I had to carry that around in side me on this morning's ride! Does it really matter? I've just swopped my original saddle on my new Spesh Secteur for a *heavier *Brooks Swift. I've been out for a ride and I can't feel any difference (i.e.due to the extra weight). So, for the average rider, like myself, does weight really matter, which leads me further to think, that in cycling, *does the bike carry us around *( in which case our weight matters as the heavier we are the harder it could be) or *do we drive forward what is beneath us *(i.e.the actual weight of the bike, making lighter bikes easier)?


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## Banjo (24 Oct 2009)

I use my bike for all sorts of journeys,if I cram 10 or 15 kgs of shopping into the panniers its noticeably harder up hill .but that is doubling the weight of the bike ,I think for most of us a pound or two isnt going to notice.


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## MajorMantra (24 Oct 2009)

In real term small weight differences shouldn't really matter unless you're racing. That said, lighter bikes feel livelier and are IMO just a little bit more fun to ride. It's nicer to go slightly faster on a light bike than a bit slower on a heavier bike. 

Matthew


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## darkstar (24 Oct 2009)

Well i suppose for the average rider body weight only makes a difference if at the extremes, just a few extra kg's would make minimal difference.
As for racers body weight makes a HUGE difference, a good example is the fairly recent weight loss Brad Wiggins has gone though, he is now about 2% body fat which is average for tour riders. It means you don't have to carry around access, useless weight i suppose.


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## JtB (25 Oct 2009)

Always makes me smile that you can pays loads of £££ just to save a few grams of weight. My ancient Carlton weighs over 15kg and when I returned to cycling 16 months ago it was an absolute 'battle laden tank' to drag up the hills. But since then, I've lost about 16kg in weight (effective weight of my bike is now -1kg ), changed the bottom bracket bearings, cleaned and re-greased the wheel bearings, changed the rear block, renewed the chain and it goes like an absolute dream now (even up the hills).


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## Steve Austin (25 Oct 2009)

simply put, yes it does matter.

a 40lb bike is harder to propel than a 15lb bike. its as simple as that.
of course if the rider is 300lb, they might be better off trying remove some of their weight than spending thousands trimming a lb off their bike, but then even a large rider will benefit from a lighter bike.


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## Alan Frame (25 Oct 2009)

But, presumably, a heavier bike/rider descends faster, making up some of the time they lost going up the hill in the first place.


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## Steve Austin (25 Oct 2009)

lol very true Alan


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## aJohnson (25 Oct 2009)

Alan Frame said:


> But, presumably, a heavier bike/rider descends faster, making up some of the time they lost going up the hill in the first place.



It may save seconds on the descent but how much longer would it add onto the ascent?


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## andrew_s (25 Oct 2009)

As a rough handle, 5kg less weight would save me about 2 minutes on a moderate Alp of 8km at 6%, out of about 45 minutes (with my fitness levels as they were last time I paid attention to time up passes). 
The fitter you are, the less time difference it makes, so a TDF rider would lose maybe 50sec for carrying an extra 5kg
It doesn't make any difference whether the weight comes off your waist, out of your panniers or off the bike. 
5kg is about the difference between a touring bike and an average sportif's bike. If you entered an event like the Marmotte (Croix de Fer, Telegraphe, Galibier, Alpe d'Huez), you'd probably take 25-30 minutes off your time by swapping a Galaxy for the latest carbon fibre bling, no training required.

Descents will depend on what the limiting factor is. If it's your nerve, you won't gain any time from a heavier bike.


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## Dayvo (25 Oct 2009)

aJohnson said:


> It may save seconds on the descent but how much longer would it add onto the ascent?



Ride on the flat, or just on routes with downhills!


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## JtB (25 Oct 2009)

Steve Austin said:


> of course if the rider is 300lb, they might be better off trying remove some of their weight than spending thousands trimming a lb off their bike, but then even a large rider will benefit from a lighter bike.


 Agreed, but I think the fact my bike was heavier was what helped me to lose those lbs faster. 



Alan Frame said:


> But, presumably, a heavier bike/rider descends faster, making up some of the time they lost going up the hill in the first place.


 That's not necessarily a good thing if your brakes aren't brilliant.


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## g00se (25 Oct 2009)

Did you realise that once you've got going, heavier bikes are better when cycling against the wind. Momentum and all that.


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## jimboalee (25 Oct 2009)

I can't be bothered to repeat all what I've already said months ago, so here's a link to a site that explains all.

http://www.analyticcycling.com/ForcesPower_Page.html


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## Garz (25 Oct 2009)

It's not like you to not be bothered jimbo...


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## chris667 (25 Oct 2009)

It only matters if you're at a standard where other people are prepared to pay for your bikes.

For general use, it's no difference at all, although a better quality machine is generally nicer to use than a bad one.


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## yenrod (25 Oct 2009)

> Weight! Does it really matter? 

In my opinion (weight of the bike) is a 50/50 matter on the flat yet, obviously uphill it'll have an effect..the lighter the bike the better..BUT strength for a given weight of rider is a big FACTOR...I'm having a frame built up and had a tubeset recommended for my weight..which made me feel a bit sidelined though I know it'll be strong or should be.


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## SoulOnIce (25 Oct 2009)

jimboalee said:


> I can't be bothered to repeat all what I've already said months ago, so here's a link to a site that explains all.
> 
> http://www.analyticcycling.com/ForcesPower_Page.html



Wow - nice one. For maths geeks like me it's always interesting to see the models


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## johnr (25 Oct 2009)

I start my daily commute with a couple of miles uphill, the second mile pretty stiff. It might be psychological, but I notice significant differences when I'm carrying stuff to work. I'd add that the ride after pumping up the tyres and lubricating the chain also seems noticably nippier too.

But all in all, it's the direction of the driving wind which is the main determinant of performance.


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## jimboalee (25 Oct 2009)

Garz said:


> It's not like you to not be bothered jimbo...



Had a chicken cooking and I could smell it.


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## Crankarm (25 Oct 2009)

It's not exactly rocket science. If you want to go faster you have to increase your power to weight ratio. Stop eating cakes, buns, crisps and pizzas. Lose a few kgs and build up your power and stamina. A ligher bike is reducing the amount of weight you have to move so again better a light bike than a tank. Plus they are much more enjoyable to ride.


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## scook94 (25 Oct 2009)

What would be classed as "heavy" for a bike these days?


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## dodgy (25 Oct 2009)

It's the accumulation of incremental weight benefits that really show up on a bike. I doubt if anyone can feel the difference if they change a saddle for a heavier or lighter one. I've never bothered changing components to save weight (with the exception of wheels), I wait for a new bike rather than upgrade.
My winter bike is a Giant TCR2 with full mudguards, it always feels so much slower than my carbon Dolan. This is because it is (slower), in Sporttracks I can see the trends when I compare my performance on each bike, there's a roughly 4lbs difference between them. But I had a niggling suspicion that the handling, performance and feel of the slower bike was down to the wheels on it. So I swapped the wheels from my Dolan (Mavic Aksium 2006 wheels on the TCR2) onto the TCR2 and the difference was amazing! It felt almost like I was on the Dolan.
So now when I read that wheel 'X' felt better than wheel 'Y' in a magazine bike test, I no longer scoff at it. The weight of my Dolan wheelset is about 1600g and the TCR2 wheels are closer to 2000g, that 400g of rotating weight can sure be felt, trust me.


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## Cubist (26 Oct 2009)

I can understand the weight of the bike being a factor if it was a huge difference, but, and Jimbolea may be able to help me out with this one (my working life consists of hitting people, not maths) 

I weigh about 100kg. It takes a lot of energy to haul my carcase anywhere, but if I am then hauling a bike with me, (or am I using the bike to do the hauling) a kg of weight added to the bike is only one percent of the total package. WIll there be a significant difference between say a 9kg bike or a 12 kg bike, all other factors being equal?

I suppose part of it is that of that 100kg body weight, a significant percentage is actually providing the power to drive the package, but then that has more to do with strength and fitness rather than just weight.


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## Steve Austin (26 Oct 2009)

Cubist. yes. a 12kg bike will have heavier wheels, as has been said propelling heavy wheels make a huge difference to any bike. 
All riders will benefit from the lightest bike they can afford. Magnus backstedt rode a very light bike, and he was a big lad. 

I've got several road bikes. heaviest about 25lb, lightest 15lb. I know which is easier to pedal up hills and for long distances


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## knapdog (26 Oct 2009)

Steve Austin said:


> I've got several road bikes. heaviest about 25lb, lightest 15lb. I know which is easier to pedal up hills and for long distances



In relation to above quote where you believe the lighter bike will be faster, again, I wonder, what if there are two people of equal fitness cycling over a given distance. One weighs in the region of 100kg on the 15lb bike and the other weighs around 70kg on the 25lb bike. Which one will fare better? You've all given great replies to my post but I'm still a little perplexed and will repeat my initial post query: *Do we carry the bike or does the bike carry us?*


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## Cubist (26 Oct 2009)

knapdog said:


> In relation to above quote where you believe the lighter bike will be faster, again, I wonder, what if there are two people of equal fitness cycling over a given distance. One weighs in the region of 100kg on the 15lb bike and the other weighs around 70kg on the 25lb bike. Which one will fare better? You've all given great replies to my post but I'm still a little perplexed and will repeat my initial post query: *Do we carry the bike or does the bike carry us?*



There's gotta be a "both" style answer to this. Without the bike we can't go very fast. With the right bike we can (well, some of us can). Therefore the bike is a machine which makes us go faster. The machine must be efficient, in other words it must be worth our while expending the energy to get the bike AND us moving faster than if we didn't have the bike at all. 

Logically that therefore means that there must be a balance point where any heavier, and the effort of making the bike move would outweigh the benefits, in other words it was so heavy we might as well walk anyway. The wrong side of that line is where the bike is so heavy we would be better off without it.

The other side of that line is that for a given amount of effort, we will benefit from riding the bike. That benefit will, for a large part of any graphic curve, show that as the bike gets lighter, so the benefits of riding it increase. That increasing benefit curve MUST however change. Once we get in and amongst the modern frames, I cannot believe that a identically geared pair of bikes, one weighing 8kg and one weighing 10kg will perform very much differently were they to be ridden by the same rider, on the same gradient. That benefit curve must flatten off, where to gain the same percentage benefit as you would at the beginning you will have to lose an impossible amount of weight from the bike



All things being equal however, and I will take some convincing that losing 30% of the weight of my rear derailleur will actually benefit me to the tune of the £799 that CRC want for it.


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## jimboalee (26 Oct 2009)

Cubist said:


> There's gotta be a "both" style answer to this. Without the bike we can't go very fast. With the right bike we can (well, some of us can). Therefore the bike is a machine which makes us go faster. The machine must be efficient, in other words it must be worth our while expending the energy to get the bike AND us moving faster than if we didn't have the bike at all.
> 
> Logically that therefore means that there must be a balance point where any heavier, and the effort of making the bike move would outweigh the benefits, in other words it was so heavy we might as well walk anyway. The wrong side of that line is where the bike is so heavy we would be better off without it.
> 
> ...



Don't start talking about 'graphic curves', they are two dirty words around here....


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## jimboalee (26 Oct 2009)

Cubist said:


> There's gotta be a "both" style answer to this. Without the bike we can't go very fast. With the right bike we can (well, some of us can). Therefore the bike is a machine which makes us go faster. The machine must be efficient, in other words it must be worth our while expending the energy to get the bike AND us moving faster than if we didn't have the bike at all.
> 
> Logically that therefore means that there must be a balance point where any heavier, and the effort of making the bike move would outweigh the benefits, in other words it was so heavy we might as well walk anyway. The wrong side of that line is where the bike is so heavy we would be better off without it.
> 
> ...



An experiment.

Put two 1 litre bottles of water on your 8kg bike. Start riding up a constant gradient hill.
Half way up, throw both bottles of water over the hedge.

Feel what happens.


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## Cubist (26 Oct 2009)

jimboalee said:


> An experiment.
> 
> Put two 1 litre bottles of water on your 8kg bike. Start riding up a constant gradient hill.
> Half way up, throw both bottles of water over the hedge.
> ...



Are they biodegradable? I think your experiments sound irresponsible!

But how can 2% of the total package make such a difference? That's what I was asking. And I think the OP was heading that way as well.


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## jimboalee (26 Oct 2009)

Cubist said:


> Are they biodegradable? I think your experiments sound irresponsible!
> 
> But how can 2% of the total package make such a difference? That's what I was asking. And I think the OP was heading that way as well.



OK, hand them to your suddenly disgruntled friend.


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## jimboalee (26 Oct 2009)

Or, ride up the hill before the experiment and place a card box on the side of the road half way up the hill.

When you do your experiment, toss the bottles into the card box.

On the way down the hill, quickly grab the card box containing the bottles and go home.


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## jimboalee (26 Oct 2009)

Or, simply drop the bottle for them to roll down the hill.

It will be an easy task to pick them up when you return to the base of the hill.


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## jimboalee (26 Oct 2009)

Or, when you are ready to shed the weight of the bottles, hang them on a 'sky hook' to keep them safe until you come back for them.


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## jimboalee (26 Oct 2009)

Or, find a hill with a pillar box half way up it. Have the bottles in a Stamped, Addressed envelope and post them back to yourself, thus transfering the work to the Royal Mail, if they are at work.


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## jimboalee (26 Oct 2009)

And the ultimate strategy. Empty the water from the bottles on the road, keeping the bottles but losing the 2 kg of water.


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## tyred (26 Oct 2009)

You could use two litre bottles of mercury to make the difference more obvious...


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## knapdog (26 Oct 2009)

Boys and Girls, I appreciate all of your comments and I'm pleased that it has started a debate! Jimboalee normally gives a lot of thought to our posts and I can fully understand that the lighter the bike, the easier ride. I can't help it if I've started to question whether shedding a few grams off the weight of the bike really makes any difference to average riders like myself if there are always going to be many different weights on top of that very bike, in other words, *us,* adding to the problem of going forwards.


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## Cubist (26 Oct 2009)

I carried the water in balloons, burst them halfway up and swallowed the evidence. My conclusions? I should have worn my waterproof socks.....

Right. Another question. If we are determined to lose 2kg from the total package, is it more efficient to shed 2kg from the rider or from the bike? Can I afford to eat more christmas pudding if Santa brings me a lighter bike?


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## knapdog (26 Oct 2009)

Cubist said:


> Right. Another question. If we are determined to lose 2kg from the total package, is it more efficient to shed 2kg from the rider or from the bike?



At last, we are getting back on to the point again, after a little frivolity! Good question, Cubist!!!!!!!


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## jimboalee (26 Oct 2009)

Cubist said:


> I carried the water in balloons, burst them halfway up and swallowed the evidence. My conclusions? I should have worn my waterproof socks.....
> 
> Right. Another question. If we are determined to lose 2kg from the total package, is it more efficient to shed 2kg from the rider or from the bike? Can I afford to eat more christmas pudding if Santa brings me a lighter bike?



Nah, what you should have done is carried the water in condoms, emptied them half way up, and re-cycled the condoms later that evening.


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## jimboalee (26 Oct 2009)

knapdog said:


> At last, we are getting back on to the point again, after a little frivolity! Good question, Cubist!!!!!!!



Try to shed mass that DOES NOT contribute toward forward ( or upward ) propulsion.
Try to increase mass that can be used to transfer chemical energy in your blood to mechanical energy at the B/B shaft.


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## jimboalee (26 Oct 2009)

jimboalee said:


> Try to shed mass that DOES NOT contribute toward forward ( or upward ) propulsion.
> Try to increase mass that can be used to transfer chemical energy in your blood to mechanical energy at the B/B shaft.



During the work to achieve the latter, you will be successful at the prior.


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## tyred (26 Oct 2009)

But how big does the weight difference need to be before the normal non-racing orientated cyclist would notice? You would certainly notice if you lost a few KGs of water half way up a steep hill. I can certainly notice the difference between my 23lb Carlton and my 45lb Rudge roadster. But would you notice a difference between a Brooks saddle and a lightweight saddle for example?

And if the bike is noticeably heavier, doesn't it just mean it needs to be geared lower for hill climbing? I can happily climb hill in my one 70" gear on my Carlton but that would be much too high for the Rudge.


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## jimboalee (26 Oct 2009)

Sometimes I wish I'd bought the 9kg sports bike instead of the 10kg sports bike.
The extra cost of the 9 kg bike was £200...

£200 for 2 lb lighter bike......

I can get that much off my waistline in a week if a train hard and eat correct.

Only when I'm down to my target weight will I deserve a lighter bike, or is it that neccessary? I've got to know this bike now so why drop it for no reason except 'self congratulatory egotism'?


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## darkstar (26 Oct 2009)

jimboalee said:


> Only when I'm down to my target weight will I deserve a lighter bike


Completely agree, i don't understand why people get the lightest bike they can possibly afford when they have extra kgs of pointless body fat! My own strength to weight ratio is not perfect so what difference does a marginally lighter frame make? if anything a heavier one will get me fitter 
Only racers or top athletes should worry about the weight of the bike when it is this marginal imo, unless a slight improvement of time is really that important to the average rider.


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## dodgy (26 Oct 2009)

I've lost a few pounds this year, but I already had a light(ish) bike. I like having a light bike and I don't feel the need to justify it. I'm going to buy a new winter bike soon and it will be well over specced for the job, but that's what I want. I love bikes and cycling.


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## just4fun (26 Oct 2009)

not just weight the components also come into it too. im in the situation of needing to loose it more from my body than my bike, that way when i get on my lead weight MTB it wont be so slow


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## arallsopp (26 Oct 2009)

I'm not getting into the science of it, but can offer this observation based upon daily 30 mile cross town commutes. The BigOrangeBeastie and Furai travel at an identical average speed. The Furai climbs a little faster, but descends a little slower. The BigOrangeBeastie has an 8kg weight penalty over the Furai, but is NO slower overall. This is based upon averaging the time over +6months of riding both.

I will concede that BoB takes more energy to ride, and that I tend to arrive more knackered when riding it than the Furai. That's why I take the Furai on anything over 150 miles...

Up to that distance, they're the same.


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## HJ (26 Oct 2009)

g00se said:


> Did you realise that once you've got going, heavier bikes are better when cycling against the wind. Momentum and all that.



From experience that just ain't so...


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## jimboalee (26 Oct 2009)

HJ said:


> From experience that just ain't so...



I had to think about that as well.

In theory, maybe so, but in practice....??? 

The classic analogy is the ping-pong ball and the steel ball bearing of the same size.
Same size, same shape but the steel ball is many times heavier.
Place them side by side and wave a hair dryer at them. See the ping-pong ball blow away in the wind while the steel ball rolls away slowly.

If you roll the balls along the floor and someone opens the door and lets a gust of wind in, the ping-pong ball will stop and roll off in the opposite direction while the steel ball carries on with little decelleration.

The same principle applies to two rolling bicycles of same cross section area and shape.

So why does it feel more difficult on a heavier bike?


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## tyred (27 Oct 2009)

I would imagine the momentum thing would apply if you were maintaining a constant speed on a flat, straight road with nothing to impede your progress but if you are speeding up and slowing down for tight corners, hills or poor surface or whatever, the heavier bike needs more energy to accelerate it again (and more braking effort to slow it down).


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## lit (27 Oct 2009)

That's why it's better to regulate your speed/pedalling.


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## jimboalee (27 Oct 2009)

tyred said:


> I would imagine the momentum thing would apply if you were maintaining a constant speed on a flat, straight road with nothing to impede your progress but if you are speeding up and slowing down for tight corners, hills or poor surface or whatever, the heavier bike needs more energy to accelerate it again (and more braking effort to slow it down).



Climbing a hill and accellerating are essentially the same thing.

The analogy for this is the old 'golf ball in a dustbin lid trick'.

Place an upturned dusbin lid on the passenger seat of a car ( or on your handlebars ). Put a golf ball in it.
As you accellerate, the golf ball rolls to the rear. How far up the curve of the dustbin lid depends on the rate of accelleration.

Now drive ( or ride ) up a hill. The golf ball will roll to the rear. How far up the curve of the dustbin lid depends on the gradient of the hill.


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## jimboalee (27 Oct 2009)

The pukka device is a 'pendulum inclinometer/accelorometer'.


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## jimboalee (27 Oct 2009)

Once you've measured your accelleration, you can go to our friend Sir Isaac and see Force = mass x accelleration.


"Shut up Jimbo, you're talking 'mumbo jumbo' again.


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## jimboalee (27 Oct 2009)

On a hill, the acceleration part is g ( 9.81 m/s^2 ) multiplied by the Sin of the inclination degrees of the hill, in addition to any 'roadspeed' acceleration happening.


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## swee'pea99 (27 Oct 2009)

andrew_s said:


> The fitter you are, the less time difference it makes, so a TDF rider would lose maybe 50sec for carrying an extra 5kg
> *It doesn't make any difference whether the weight comes off your waist, out of your panniers or off the bike. *



Six pages in, if there's been a definitive answer to this, from page one, I've not noticed it. It's always seemed to me like the nub of the matter.

Yes, it's better to lose a few pounds by cutting down on the pies. Yes, a lighter bike will, other things being equal, be an easier, faster ride than a heavier bike. But is it the weight of the bike that matters or the weight of 'the total package' as someone described it? Does losing 1Kg off the waistline and 1Kg off the bike have exactly the same effect? 

Tim Krabbe's 'The Rider':

_"Jacques Anquetil, five times winner of the Tour de France, used to take his water bottle out of its holder before every climb and stick it in the back pocket of his jersey. Ab Geldermans, his Dutch Lieutenant, watched him do that for years, until finally he couldn't stand it any more and asked him why. And Anquetil explained. 
A rider, said Anquetil, is made up of two parts, a person and a bike. The bike, of course, is the instrument the person uses to go faster, but its weight also slows him down. That really counts when the going gets tough, and in climbing the thing to do is make sure that the bike is as light as possible. A good way to do that is: take the bidon out of its holder."_

So, was Anquetil wise, or bonkers?


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## MajorMantra (27 Oct 2009)

If your climbing style involves chucking the bike all over the place whilst keeping your body reasonably still, then I suppose there could be some logic in what Anquetil said. I'm sceptical about it making much difference though and I would have thought the inconvenience of having a bottle in your pocket outweighed any possible advantages. Anquetil may have been a great rider but that doesn't make him a great physicist. 

Matthew


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## Woz! (27 Oct 2009)

Makes some sense to me - the bike will be moving far more than the rider when the rider's really going for it. If you're out of the saddle and pumping the bike will be moving side to side with every stroke, but a good rider will tend to stay vertical with just forward motion.
If you've got any extra weight on the bike then the side to side motion will be sapping a lot of energy as you have to decelerate and accellerate that weight every time the bike sways, irrespective of the forward motion of the bike. 

Personally though, my bike's a tourer and I load WAY too much junk in my panniers because I never know when you might need that yo-yo/camera/monocular (honestly*!) on my 26 mile round trip commute  


*I've yet to need the yo-yo or the monocular. But you never know.


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## knapdog (27 Oct 2009)

After analysing everyone's replies I *choose* to conclude that we and the bike are not separate, but that they both combine to total ONE weight and it is this one weight that we pedal around. Therefore, it is just as beneficial to our progress if *we* lose, for example, 2kg from our body mass as shaving 2kg off the weight of the bike. Of course, I may still be wrong!!!!!!!


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## MacB (27 Oct 2009)

here's a linky for you

http://www.smartcycles.com/bike_weight.htm


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## swee'pea99 (27 Oct 2009)

Well, that seems pretty unambiguous. According to that article, it makes _no_ difference whether the weight is in the bike or the rider - it is only the 'total package weight' that matters. 

Have to say I'm sceptical.  I reckon there _is_ a bigger advantage in knocking a kilo off the bike than off the rider. I also reckon it makes a significant difference _where_ you knock that weight off. 

I've heard it said that 'an ounce off the wheels equals a pound off the frame'...I think there's a lot of truth in that. And if there is, it does kind of call into question the rather simple assumptions made in that article.


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## tyred (27 Oct 2009)

A lighter wheel will be easy to rotate and get up to speed but then again there is the question of momentum once you have your wheels up to speed.

It's similar to the difference between fitting a car engine with a heavy or a lightweight flywheel.

Isn't one of Alex Moulton's arguments in favour of small wheels is that they are both lighter and stiffer than a large wheel?


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## knapdog (27 Oct 2009)

Does a heavier wheel add more centrifugal force to the circumference when rotating, which, in turn, could make the bike heavier?


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## swee'pea99 (29 Oct 2009)

knapdog said:


> Does a heavier wheel add more centrifugal force to the circumference when rotating, which, in turn, could make the bike heavier?


Ingenious but deranged. If you think about it, the centrifugal force is acting equally in all directions - eg, up exactly as much as down. So it can't be 'making the bike heavier'. 

I can't get my head round the physics of the thing at all, but I do know from personal experience that swapping for lighter wheels might make only a very marginal difference - way under a kg - to the 'total package weight'...but it makes a helluva difference to the ride.


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## Woz! (29 Oct 2009)

Heavier wheels will have more of a gyroscopic affect than lighter ones...


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## dodgy (29 Oct 2009)

knapdog said:


> Does a heavier wheel add more centrifugal force to the circumference when rotating, which, in turn, could make the bike heavier?



Here's a fun experiment, take off the front wheel (less messy) and hold it at the quick release with both hands (one hand each side of the wheel hub), then spin it as fast as you can with your fingers (maybe ask someone to help). Once the wheel is spinning, try to turn the wheel so it tilts around as if you were steering it.

Come back and tell us how it feels


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## tyred (29 Oct 2009)

Bicycle wheels and tyres are usually very poorly balanced. If you had wheels like that on your car, it would be a struggle to drive it.


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## jimboalee (29 Oct 2009)

dodgy said:


> Here's a fun experiment, take off the front wheel (less messy) and hold it at the quick release with both hands (one hand each side of the wheel hub), then spin it as fast as you can with your fingers (maybe ask someone to help). Once the wheel is spinning, try to turn the wheel so it tilts around as if you were steering it.
> 
> Come back and tell us how it feels



Take the skewer out.
Spin it REALLY fast at an angle to the ground.
Now hold the wheel on one fingertip.

Precession 


Lighter rims are easier to turn because of the shorter radius of gyration.


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## Dave5N (1 Nov 2009)

jimboalee said:


> Take the skewer out.
> Spin it REALLY fast at an angle to the ground.
> Now hold the wheel on one fingertip.
> 
> ...




I did that.

I got nutation


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## jimboalee (1 Nov 2009)

Dave5N said:


> I did that.
> 
> I got nutation



I'll nod my head to that.


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