## Why do better wheel sets work better?

warthog1
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### Re: Why do better wheel sets work better?

winstonw wrote:The point I was flamed for on another thread is the very reason wheel manufacturers don't make one aero wheel (a full disk).

http://www.bicycles.net.au/forums/viewtopic.php?f=12&t=60978&start=25

No you were "flamed" (I would say disagreed with) for arguing without supplying evidence, yet you expected evidence from the bloke you were arguing with.

You can only use a disc for TT's on the road by the way, and then only on the rear, they are not allowed in bunch start races under uci rules.

LM324
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### Re: Why do better wheel sets work better?

looking at this thread it makes me wonder why wheelset reviews say that because of the weight "it takes longer to get up to speed" and "you can feel the extra weight when climbing" if weight really makes such a small difference

snortin
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### Re: Why do better wheel sets work better?

winstonw wrote:I've read a paper that shows asymmetrical aero positioning offers performance significant smaller CdA for variable velocity/yaw angles.
The majority of aero tests don't acknowledge this. They just presume CdA varies minimally for all unstable yaw/velocity combos , and use an average for the same rider position. This is the problem though isn't it. The maths to accurately model real world conditions are complex, and presumptions are made to simplify.
The point I was flamed for on another thread is the very reason wheel manufacturers don't make one aero wheel (a full disk). Obviously they realize drag is not a constant across all yaw/velocity combos and unstable states of each.

Why make it so complicated? I am certain that if asymmetrical positioning helps reduce CdA for a range of wind speeds/angles, and that an athlete can maintain the same power relationship with this position (ie produce enough power in the aero position nominated) then they will adopt that position for the given variable speed/yaw angles.

I don't think you are getting my point - I acknowledge that wind speed and direction do vary in real world conditions. You should be able to get a fairly good estimation of average wind speed/direction on the day of an event. If you know that X brand wheels handle this average better than Y brand (measured in the wind tunnel) then choose X brand. Similarly with position - find the one that best fits your power relationship for the expected conditions.

And by the way, I think that if the paper you were reading was talking about variable velocity and yaw angles then you should treat it with some scepticism, because anybody writing such a paper would know that velocity has a direction and speed (and as such would either refer to velocity or speed and yaw).

Getting back to the original question - I would expect a "better" wheelset would offer me a combination of:
improved aerodynamics for a particular scenario
reduced weight
increased reliability (obviously to a point)
reduced friction in the hub

Then I could judge whether it was worth spending the extra money on "better" wheels or if I should just improve my training

ausrandoman
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### Re: Why do better wheel sets work better?

Philipthelam wrote:looking at this thread it makes me wonder why wheelset reviews say that because of the weight "it takes longer to get up to speed" and "you can feel the extra weight when climbing" if weight really makes such a small difference

That's an easy question: people feel what they expect to feel.

I'd like to get some of these reviewers to do a randomised double blind trial* with two sets of wheels, one of which has 200** grams of weight hidden under the rim tape of the back wheel. No picking up the wheels or bike - just get on the bike, ride up a hill, come back swap wheels, do it again then tell us which set is heavier. I honestly don't know if the difference would be detectable. For all I know, it might be easy to tell with 99% accuracy but I am not interested in hearing opinions from people who say they can or can't until they have done repeated, randomised, controlled A/B comparisons.

*That is, not even the person handing the tester the next bike knows if it has the heavy wheel or the light wheel.

**I've never noticed myself climb faster after I've stopped for a p___.
Nobody younger than <del>27</del> 28 has experienced a month cooler than the 20th century average.

merlin6014
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### Re: Why do better wheel sets work better?

ohexploitable wrote:
merlin6014 wrote:Ive gone from a 2000g wheelset (shimano r501s) to a 1330g carbon wheelset and the difference is night and day. I am absolutely smashing pr's. Its particularly noticeable uphill. Definaty worth the money.

"Ive gone from a 2000g wheelset (shimano r501s) to a 1330g carbon wheelset and the difference is night and day. My wallet is a lot emptier and I am riding faster purely because for a small part, the placebo makes me feel better but mostly because I'm fitter than I was before."

Yes i guess all the research is just made up? All these triathletes must be wrong. Brb going to my local tri club to tell them they are all wasting money. Its pretty simple science (aero that is - the new wheelset is 58mm deep vs 20mm old one).

LM324
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### Re: Why do better wheel sets work better?

Well then...

If weight mean so little on wheelsets, why do companies even make light wheels? Why do people even buy light wheelsets? Heck, why do pros even ride with light wheels?

This must be THE BIGGEST CONSPIRACY TO DO WITH CYCLING!!!

They're tricking us all!!!

p.s the wheels i have on my roadie are 2500 grams

biker jk
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### Re: Why do better wheel sets work better?

Philipthelam wrote:Well then...

If weight mean so little on wheelsets, why do companies even make light wheels? Why do people even buy light wheelsets? Heck, why do pros even ride with light wheels?

This must be THE BIGGEST CONSPIRACY TO DO WITH CYCLING!!!

They're tricking us all!!!

p.s the wheels i have on my roadie are 2500 grams

A heavier aero wheelset will be faster (except if you were just doing steep climbs) than a lighter non-aero wheelset, so weight isn't always the key consideration. In any case, what's appropriate for the Pro Peloton (which has support vehicles to provide an instant wheel change and whose average weight is pretty low) may not be the right choice for recreational riders (where durability becomes much more important).

LM324
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### Re: Why do better wheel sets work better?

Well I guess I have got the worst wheels... They are heavy and non-aero

winstonw
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### Re: Why do better wheel sets work better?

snortin wrote:And by the way, I think that if the paper you were reading was talking about variable velocity and yaw angles then you should treat it with some scepticism, because anybody writing such a paper would know that velocity has a direction and speed (and as such would either refer to velocity or speed and yaw).

speed is commonly called velocity in equations and papers i.e. Vwind at alpha wind angle.
combined speed and direction can only be integrated on a velocity vector chart.
Last edited by winstonw on Thu Feb 28, 2013 5:35 pm, edited 1 time in total.

winstonw
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### Re: Why do better wheel sets work better?

warthog1 wrote:No you were "flamed" (I would say disagreed with) for arguing without supplying evidence, yet you expected evidence from the bloke you were arguing with.

I didn't make an emphatic generalized statement that contradicted wheel manufacturers' production of deep section wheels of varying depth.
Most manufacturers are reasonably transparent about their R&D validating such, which anyone on that thread could have read, but obviously didn't, or couldn't comprehend....much easier to bleat, ridicule, and flame.

Mulger bill
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### Re: Why do better wheel sets work better?

winstonw wrote: i.e. Vwind at alpha wind angle.

My physics may be a little rusty but doesn't having speed and direction make that a vector?
I welcome either correction or confirmation from a more polished physicist...
...whatever the road rules, self-preservation is the absolute priority for a cyclist when mixing it with motorised traffic.
London Boy 29/12/2011

winstonw
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### Re: Why do better wheel sets work better?

Mulger bill wrote:
winstonw wrote: i.e. Vwind at alpha wind angle.

My physics may be a little rusty but doesn't having speed and direction make that a vector?
I welcome either correction or confirmation from a more polished physicist...

hahaha...thanks for the entertainment Bill. I peppered the screen with a couple of bean sprouts and lentils when I read that.
Are you rusty on your nutrition science too?

KenGS
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### Re: Why do better wheel sets work better?

ausrandoman wrote:**I've never noticed myself climb faster after I've stopped for a p___.

Pint???
--Ken
Helmets! Bells! Rego!

clackers
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### Re: Why do better wheel sets work better?

Mulger bill wrote:My physics may be a little rusty but doesn't having speed and direction make that a vector?
I welcome either correction or confirmation from a more polished physicist...

You may go to recess early, MB!

Velocity is a vector, speed has no direction so is a scalar.

winstonw
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### Re: Why do better wheel sets work better?

clackers wrote:
Mulger bill wrote:My physics may be a little rusty but doesn't having speed and direction make that a vector?
I welcome either correction or confirmation from a more polished physicist...

You may go to recess early, MB!

Velocity is a vector, speed has no direction so is a scalar.

toolonglegs
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### Re: Why do better wheel sets work better?

Don't you mean yawn?

trailgumby
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### Re: Why do better wheel sets work better?

When I went from a basic entry level Mavic XM117 wheelset to Crossmax SLRs on my mtb, I noticed some pretty substantial differences. The Crossmaxes were acquired as part of a secondhand purchase deal when I bought my son his first decent dually.

The Crossmaxes definitely rolled faster. The most noticeable first impression was simply rolling down the hill. I had been a sceptic. I liked the bling but wasn't expecting much in performance difference. I must say I was surprised by how marked the difference was. Can I put numbers on it? No. But it was enough to reverse my scepticism. This with 2.4" wide knobbly rubber - aero not a factor. The Crossmaxes had new rubber with full height (unworn) knobs, which should be slower.

The second difference was the plantedness of the wheels in cornering, even on the road. The extra stiffness made the bike, already with the stiffest fork in its class on board, a lot more confidence inspiring to ride. It made the suspension do the work, instead of the wheels flexing.

There were other differences, but not as relevant to road riding.

trailgumby
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### Re: Why do better wheel sets work better?

This is where I think lighter weight for a given aero performance can make a difference in road riding and racing, and probably more in crit racing.

Once the race has taken shape, and most people are at their limits, there is a lot of testing your competitors going on with little accelerations and trying to gap your opponents to shake them out of your slipstream. Alternatively, you're on the rivet trying not to be gapped. On crit courses, there's the accordion effect coming into and out of corners, where you have to slow down, corner hard, and accelerate quickly again.

Anything that reduces rotating mass, helps put power to the ground better, and allows you to accelerate more quickly to make it easier to stay on the wheel in front, or help stop you losing the wheel in front in those surges, is going to have a disproportionately high payoff compared to the difference it would make riding at a steady state, in a wind tunnel, or riding alone, whether or not hills were involved.

The cheapest way to maximise this effect is to buy lighter tyres!
Last edited by trailgumby on Sat Mar 09, 2013 11:02 am, edited 1 time in total.

Nobody
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### Re: Why do better wheel sets work better?

trailgumby wrote:When I went from a basic entry level Mavic XM117 wheelset to Crossmax SLRs on my mtb, I noticed some pretty substantial differences. The Crossmaxes were acquired as part of a secondhand purchase deal when I bought my son his first decent dually.

The Crossmaxes definitely rolled faster. The most noticeable first impression was simply rolling down the hill. I had been a sceptic. I liked the bling but wasn't expecting much in performance difference. I must say I was surprised by how marked the difference was. Can I put numbers on it? No. But it was enough to reverse my scepticism. This with 2.4" wide knobbly rubber - aero not a factor. The Crossmaxes had new rubber with full height (unworn) knobs, which should be slower.

The second difference was the plantedness of the wheels in cornering, even on the road. The extra stiffness made the bike, already with the stiffest fork in its class on board, a lot more confidence inspiring to ride. It made the suspension do the work, instead of the wheels flexing.

There were other differences, but not as relevant to road riding.

Couple of questions:

Did the roll down experience happen on the same tyres with the same pressure?

What was the spoke tension like on the former wheel?

I believe many are riding around on spokes that the tension has slowly slackened as the nipples have slowly unwound over the years. Then they swap to a higher spec wheelset and the difference is amazing. I think it would be significantly less amazing if the original wheels had been re-tensioned before a comparison.

trailgumby
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### Re: Why do better wheel sets work better?

Good question, nobody.
Same pressure. I'm a bit anal about that as it makes quite a difference to tyre behaviour on the trail.
Expensive wheelset had tyres of the same purchase date with but unworn knobs, which should have made rolling resistance worse, not better.
Spoke tension on cheap wheelset could have been better and was probably a factor (wheelset since sold). but I still notice the difference between my mid-range tubeless wheelset, which are tensioned up quite tight, and the SLRs when I pull them out a couple of times a year for racing.

Here's an interesting test.
We all know that when you drop a couple of marbles from the same height off the Leaning Tower of Pisa that they land at pretty much the same time, even if one is big and another small.
Try rolling a big marble and a small marble down a two-car hotwheels race car track.
Which would you expect to win?
Hint: I did this when I was 8 ... and was terribly confused by the results

Nobody
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### Re: Why do better wheel sets work better?

trailgumby wrote:Here's an interesting test.
We all know that when you drop a couple of marbles from the same height off the Leaning Tower of Pisa that they land at pretty much the same time, even if one is big and another small.
Try rolling a big marble and a small marble down a two-car hotwheels race car track.
Which would you expect to win?
Hint: I did this when I was 8 ... and was terribly confused by the results
Like this?
Yes, but Alex would also tell you that wheel weight is not significant when compared with the rest of the bike and rider weight.

I've had my heavy touring wheels with disc (usual ride) and 16/20 spoke 105 race wheels on the same bike with the same tyres and could hardly notice a difference. Interesting link below on blog to do with aero on non-racing bikes.
http://janheine.wordpress.com/2012/05/0 ... -bicycles/

Mulger bill
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### Re: Why do better wheel sets work better?

toolonglegs wrote:Don't you mean yawn?

...whatever the road rules, self-preservation is the absolute priority for a cyclist when mixing it with motorised traffic.
London Boy 29/12/2011

winstonw
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### Re: Why do better wheel sets work better?

toolonglegs wrote:Don't you mean yawn?

like your 18mth self diagnosis of glut strain, or was it a hammie, or is it a disc?

lucky aero wheels and cleat covers compensate a stiff back...but which aero wheels???

trailgumby
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### Re: Why do better wheel sets work better?

Nobody wrote:Like this?
Yes, but Alex would also tell you that wheel weight is not significant when compared with the rest of the bike and rider weight.

I've had my heavy touring wheels with disc (usual ride) and 16/20 spoke 105 race wheels on the same bike with the same tyres and could hardly notice a difference. Interesting link below on blog to do with aero on non-racing bikes.
http://janheine.wordpress.com/2012/05/0 ... -bicycles/

Yeah, like that.

To expand on what I'm saying: in a racing situation, where a metre or two coming out of a corner or bridging across to a jumping rider at the start of an acceleration can make quite a difference to whether you get into the breakaway group or fall off the back, I can see where saving a couple of hundred grams could have a disproportionate impact.

But yeah, generally, aero trumps light weight. On a bike you spend a lot more time at steady state than accelerating and braking.

toolonglegs
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### Re: Why do better wheel sets work better?

winstonw wrote:
toolonglegs wrote:Don't you mean yawn?

like your 18mth self diagnosis of glut strain, or was it a hammie, or is it a disc?

lucky aero wheels and cleat covers compensate a stiff back...but which aero wheels???

Glad you can laugh at other peoples suffering ... like I say... yawn

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