Wheels Lab Tests

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C36
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by C36

NordicSal wrote:
Tue Jan 24, 2023 9:53 pm
Would be really interesting if someone could write down a few points about how to read this info.

Points answering questions not limited to but like these:

What is good/bad stiffness and why?
What is good/bad aero and why?

So much knowledge in here that's not shared because a lot of you are already in the know.
There is some subjective and rational aspect on the ranking.

Aero: ideally the lower the better, to be taken with a pinch of salt,
- those values are normalized from measures taken from -20 to 20 deg yaw angle (apparent wind angle) with a weighting (on top of my head you spend 90% of the time in less than 7deg yaw, so low yaw angle have more weight than large ones).
- Sometimes Tour publish sensitivity to lateral wind (how much instability is transmitted to the direction), if you get the magazin the details are there.
- Another limiting factor is the tire-impact, see below.

Stiffness: Stiffness impacts few rational and "feeling" aspect
- rational the power: long story short, out of the saddle you go faster. You have better pedal efficiency, out of your power, more is used to move you forward and in accelerations you have higher power-peaks.
- feelings, more difficult to quantify (better steering precision, more reactive bike).
--> Below 40N/mm I consider it quite too flexible (flagged in red) and the ideal being above 50N/mm (55 will flag green).
- One point I may illustrate later, wheels being assymetric (either the disc or the disc and the cassette) they are never as stiff in both direction but while some have few % difference, some display large variations.
Mr.Gib wrote:
Sat Jan 28, 2023 11:36 pm
Just looking at that data, I am pleased to see that wider doesn't seem to be slower. All the 30mm and wider rims of adequate depth performed well. I always wondered what price I was paying for running 32mm wide rims. Apparently none according to this testing. However, assuming equal tire/rim aero optimization, a 28mm wide rim must be faster than a 32mm wide rim? Perhaps the differences are so small that they cannot be measured.
Tour test with a GP4k in 25mm (that measures 27mm wide on a narrow rim -17c?- so likely close to 29 on 21 inner rim) so it benefits to wide rims. From the table published above I would say that Zipp 303, Bontrager and Cadex benefit from this tire-size when the Zipp 454, Cosmic Ultimate, Cadex 36 and LW would save 1-2 watts with an 25-27mm real width tire.
Last edited by C36 on Mon Jan 30, 2023 9:59 pm, edited 1 time in total.

NordicSal
Posts: 279
Joined: Thu Feb 14, 2019 11:09 pm

by NordicSal

C36 wrote:
Mon Jan 30, 2023 4:19 pm


There is some subjective and rational aspect on the ranking.

Aero: ideally the lower the better, to be taken with a pinch of salt,
- those values are normalized from measures taken from -20 to 20 deg yaw angle (apparent wind angle) with a weighting (on top of my head you spend 90% of the time in less than 7deg yaw, so low yaw angle have more weight than large ones).
- Sometimes Tour publish sensitivity to lateral wind (how much instability is transmitted to the direction), if you get the magazin the details are there.
- Another limiting factor is the tire-impact, see below.

Stiffness: Stiffness impacts few rational and "feeling" aspect
- rational: out of the saddle you have better pedal efficiency, then out of your power, more goes to make you move forward and in accelerations you have higher power-peaks
- more difficult to quantify (better steering precision, more reactive bike).
--> Below 40N/mm I consider it quite too flexible (flagged in red) and the ideal being above 50N/mm (55 will flag green).
- One point I may illustrate later, wheels being assymetric (either the disc or the disc and the cassette) they are never as stiff in both direction but while some have few % difference, some display large variations.
Quite interesting that so many wheels are deemed "too flexible".

A ~50 mm wheelset is hard to make stiff enough it seems? How come they are flexible then? To save weight or just poorly manufactured?

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C36
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by C36

NordicSal wrote:
Mon Jan 30, 2023 4:43 pm
Quite interesting that so many wheels are deemed "too flexible".
A ~50 mm wheelset is hard to make stiff enough it seems? How come they are flexible then? To save weight or just poorly manufactured?
In 15 years wheel stiffness has dropped, I see few reasons:
- Weight and aero have been easier to market than stiffness. Weight you use a scale, aero you make fancy graphs with nice wind-tunnel pictures. Aero, you can simulate a lot on computer, simulate wheel stiffness is more complicated, you have the tension, the tension drop with the tire inflation, the tension changes with the torque coming from the chain... some understand it, some others no.
- Spokes technology made a step change with the CX-Ray, you could have thin spokes that were not breaking anymore... they were lighter but flexible... nevertheless theybecame the norm for high-end wheels. I need to x-check numbers but I think there is a 10% to loose here
- We moved from 28 to 24 spokes at the rear, it saved weight and benefit aero. I need to x-check numbers but I think there is another 10% to loose here
- Hub geometry, many hubs have very conservative geometry (starting with the popular DT) that drops lateral stiffness. Here few % to lose (3 or 4% for 1mm narrower flange). Not sure why, if that's to avoid that a poorly adjusted deraileur hit the spokes?

Recently we saw few interesting changes:
- DT using larger spokes at the rear (Aerocomp rather than Aerolight, a CX-ray equivalent), something Campagnolo was already doing 20 years ago
- Some brands going 24 triplet (rather than 21) like Cadex (where Hunt went to 20 spokes and a low stiffness)
- Mavic did a lot of work around this: the Tra-Comp (carbon spokes working in compression too), the Ultimate series...

TobinHatesYou
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Joined: Mon Jul 24, 2017 12:02 pm

by TobinHatesYou

Don’t forget disc brake hubs = worse bracing angles on the NDS.

NordicSal
Posts: 279
Joined: Thu Feb 14, 2019 11:09 pm

by NordicSal

C36 wrote:
Mon Jan 30, 2023 5:21 pm
NordicSal wrote:
Mon Jan 30, 2023 4:43 pm
Quite interesting that so many wheels are deemed "too flexible".
A ~50 mm wheelset is hard to make stiff enough it seems? How come they are flexible then? To save weight or just poorly manufactured?
In 15 years wheel stiffness has dropped, I see few reasons:
- Weight and aero have been easier to market than stiffness. Weight you use a scale, aero you make fancy graphs with nice wind-tunnel pictures. Aero, you can simulate a lot on computer, simulate wheel stiffness is more complicated, you have the tension, the tension drop with the tire inflation, the tension changes with the torque coming from the chain... some understand it, some others no.
- Spokes technology made a step change with the CX-Ray, you could have thin spokes that were not breaking anymore... they were lighter but flexible... nevertheless theybecame the norm for high-end wheels. I need to x-check numbers but I think there is a 10% to loose here
- We moved from 28 to 24 spokes at the rear, it saved weight and benefit aero. I need to x-check numbers but I think there is another 10% to loose here
- Hub geometry, many hubs have very conservative geometry (starting with the popular DT) that drops lateral stiffness. Here few % to lose (3 or 4% for 1mm narrower flange). Not sure why, if that's to avoid that a poorly adjusted deraileur hit the spokes?

Recently we saw few interesting changes:
- DT using larger spokes at the rear (Aerocomp rather than Aerolight, a CX-ray equivalent), something Campagnolo was already doing 20 years ago
- Some brands going 24 triplet (rather than 21) like Cadex (where Hunt went to 20 spokes and a low stiffness)
- Mavic did a lot of work around this: the Tra-Comp (carbon spokes working in compression too), the Ultimate series...
Thank you very much for elaborating it all.

I like my ERC 1100 wheelset, last gen. Only carbon rims I've ever tried. It's made me wonder what I am losing out of in terms of stiffness.

On the other hand, I am very happy with it, and ignorance is probably bliss at some point. The DT hubs are so durable for me, and I am not taking any good care of them (riding in all weather here in Denmark and only getting service once a year).

I am probably better off ignoring my newly gained knowledge and try not to seek a stiff wheelset to try out.

Steadimann
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Joined: Tue Aug 31, 2021 1:50 pm

by Steadimann

I ride Princeton Wake wheels, had a chance to try Lightweight Meilenstein wheels. I can tell you this: with Lightweight you feel like riding a go cart, while with normal wheels - more like a motorcycle. But.. it is stiff, depending on roads it can be tiring, depending on wheels it can feel softer if you have wider rims and bigger tires, but OMG stiff wheels are amazing when climbing... every leg stroke feels like a push from behind. If i had a chance to choose really soft or really stiff - i would go for stiff. Stiff wheels feel direct, I like it. There should be some unified stiffness test so we would know how stiff are all wheels besides just reviewers praisinf them to be such..
p.s. Thinking to get a set of new Mavic wheels with carbon spokes, half the price of LW, same strengrh, same weight.

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C36
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by C36

Is the "Light, aero, stiff, pick two... " really valid?

It's indeed difficult to make a light, aero and stiff wheel all together, let's plot the data
- Inertia measured (as energy to accelerate), lighter rims will display less inertia and FEEL better.
- Front stiffness and Rear stiffness measured in N/mm
Presented in absolute values and relative to best performance (%).

Image

Quite clear how difficult it is to have everything in the same wheel, then the great work from either Cadex or Mavic. All other wheels drop 10 or 20% on each measure very quickly

Image


If we sum inertia+stiffness we have something probably even clearer. A wheel that would score the best in each measure will score 300%
Image

NordicSal
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Joined: Thu Feb 14, 2019 11:09 pm

by NordicSal

Great. Now I want the new Mavic set. Only tempted if we get close to a 50% price drop though - we'll see.

TobinHatesYou
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by TobinHatesYou

The Mavics lose 2W in aero drag to the Cadex at 45km/h and you’d be stuck with 26.5mm WAM tires if you care about the 105% rule.

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C36
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Joined: Fri Mar 03, 2017 3:24 am

by C36

The Cadex will offer a wider playground with its extra 2mm width.
If you have a need of very wide tires, above 28 (and we know you do) and want remain within the "105%" guideline, it's could be a limiting factor. This being said, if you ride on what I would call "normal" roads on this side of the Atlantic, 25-26mm would be your best performance combination with yet a more than good performance with 28mm tires (and nothing stops you to go hybrid with 25 front, 28 rear).

From aero POW, we enter intro the grey area of the set-up limitation. We need to factor the tire used to normalize Tour results: the 25mm GP4K favours wide rims. On a C17mm rim the tire already measures almost 27mm, on a Hollowgram wheel (19c) mines were 28mm. With a real 25-26mm tire, the Mavic will likely close the gap so could do the Cadex 36 (the LW and its 24mm would still be too narrow).

NordicSal
Posts: 279
Joined: Thu Feb 14, 2019 11:09 pm

by NordicSal

What's the drawback from the cadex wheels? They seem really cheap at like 1300 euro too.

garbageman
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Joined: Thu Nov 19, 2020 6:08 am

by garbageman

1300 euro for the front wheel maybe...msrp is 3500 USD on the cadex 50 ultra

NordicSal
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Joined: Thu Feb 14, 2019 11:09 pm

by NordicSal

Ah yes, just saw the google price..

StiffWeenies
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Joined: Sun Feb 28, 2021 3:39 pm

by StiffWeenies

Thanks for sharing! I wonder how LW are able to make their wheels so stiff? Mavic is bonded carbon spokes just like LW but the stiffness is just on par with removable carbon spokes

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C36
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Joined: Fri Mar 03, 2017 3:24 am

by C36

StiffWeenies wrote:
Sun Feb 05, 2023 2:22 pm
Thanks for sharing! I wonder how LW are able to make their wheels so stiff? Mavic is bonded carbon spokes just like LW but the stiffness is just on par with removable carbon spokes
Some speculations here: for 20 years LW is built around a same concept: spokes are connected to the rim walls and the rim is then build around them.

https://www.youtube.com/watch?v=Qa7G9B9t_qU here @ 2'17"

The spokes angles being fixed, you can't make the rim really wider or the spokes don't connect anymonger to the rim walls. That probably explains why their rims are still 24mm max. Mavic kept this type of construction with their 25mm wide rim, with quite a complex design where the spoke connect twice with the rim (and different version reach 56 and 59N/mm rear stiffness).

With a 28mm rim they came with something quite different, bonding the spoke to a Fore Insert. Could explain the stiffness drop but the rim is 12-15% lighter, 3mm wider and better suited to 25-28mm tires.
Image

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