Road Racing & Aero Wheels

[Spoked Wheels]

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.

 

[Pedrosanchezo]

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. ;-)

 

[Citius]

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.

 

[Soltydog]

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?

 

[smutchin]

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.

 

[Yellow Saddle]

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.

 

[Pedrosanchezo]

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.

 

[Citius]

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.

 

[Spoked Wheels]

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.

 

[Yellow Saddle]

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.

 

[smutchin]

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.

 

[Cyclist33]

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

 

[Cyclist33]

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...

 

[Yellow Saddle]

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

 

[Cyclist33]

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.