Aero plots for wheels

Wheels, Tires, Tubes, Tubeless, Tubs, Spokes, Hookless, Hubs, and more!

Moderator: robbosmans

Forum rules
The spirit of this board is to compile and organize wheels and tires related discussions.

If a new wheel tech is released, (say for example, TPU tubes, a brand new tire, or a new rim standard), feel free to start the discussion in the popular "Road". Your topic will eventually be moved here!
rudye9mr
Posts: 570
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr

https://altairuniversity.com/wp-content ... 11_web.pdf
^A Comparative Aerodynamic Study of
Commercial Bicycle Wheels Using CFD

Must read for those interested - shows CFD modelling and forces on different depth wells including HED tri-spoke



https://www.sciencedirect.com/science/a ... 0519305884
^CFD simulations of spoked wheel aerodynamics in cycling: Impact of computational parameters


Roval CLX ii
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DT Swiss ARC 2.0
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Hadron2
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HUNT34
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Hunt 48 limitless
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Campagnolo Bora
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wto77 in black
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WTO45
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3T Discus 45
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Vision Metron
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Last edited by rudye9mr on Tue May 23, 2023 1:19 pm, edited 3 times in total.

by Weenie


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Nickldn
Posts: 2008
Joined: Mon Mar 25, 2019 12:35 am

by Nickldn

So it looks like the real advantage to deep wheels (60mm +) comes at high yaw angles, above 10 degrees (sail effect).

Trouble is most studies suggest that unless you're riding the Ironman at Kona you're not going to experience high yaw angles very often.

Shame. I'm sticking with my WTO 45s.
Giant Propel Advanced SL Red Etap 11s Easton EC90 wheels CeramicSpeed BB Zipp SL70 bars 6.5kg

S-Works SL8 Dune White SRAM Red AXS Craft CS5060 wheels Roval Rapide bars 6.6kg

rudye9mr
Posts: 570
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr

Newer generation of aero wheels tried to focus on stability for crosswinds, minimizing steering corrections from rider.

I think they have yaw angles sorted, just rim shapes and how they interact with different size tyres to be more stable than previous iterations. Roval seems very interesting and Fulcrum indicated same with new Speeds.

Lina
Posts: 1266
Joined: Sat Sep 01, 2018 9:09 pm

by Lina

Nickldn wrote:
Sun May 21, 2023 11:04 am
Trouble is most studies suggest that unless you're riding the Ironman at Kona you're not going to experience high yaw angles very often.
As if Kona is magically the only windy place on earth. In fact it's not even that windy when speaking about places that have a lot of cyclists. Large parts of Denmark, Belgium, Netherlands, Northern and Western France, and UK are all extremely windy. And it's not like those places don't have any cyclists. Just for your own entertainment take a look at the average yearly wind speeds in Copenhagen, Brussels, Amsterdam, and Kona for example. Yeah, suddenly Kona doesn't seem that special.
Last edited by Lina on Mon May 22, 2023 10:05 am, edited 1 time in total.

HBike
Posts: 223
Joined: Sun Aug 14, 2022 8:22 pm

by HBike

Lina wrote:
Mon May 22, 2023 1:34 am
Nickldn wrote:
Sun May 21, 2023 11:04 am
Trouble is most studies suggest that unless you're riding the Ironman at Kona you're not going to experience high yaw angles very often.
As if Kona is magically the only windy place on earth. In fact it's not even that windy when speaking about places that have a lot of cyclists. Large parts of Denmark, Belgium, Netherlands, Northern and Eastern France, and UK are all extremely windy. And it's not like those places don't have any cyclists. Just for your own entertainment take a look at the average yearly wind speeds in Copenhagen, Brussels, Amsterdam, and Kona for example. Yeah, suddenly Kona doesn't seem that special.
It is not the wind per se, it is the yaw angle. Very large raw angles are rare. I posted that on another thread, but is still valid

Trek: ‘In the real world 2.5° to 12.5° are the most prevalent yaw angles riders encounter.’
Yu at Specialized adds, ‘For an average cyclist, unless you’re riding in extremely windy conditions, the typical angles are less than 10°.’
This slight difference in results is why one aero bike doesn’t look identical to another. Specialized designed the Venge ViAS based on its vision of the perfect range of yaw, while Trek designed the Madone to fit a different range.
So it seems that if you’re Peter Sagan, driving the peloton along at 50kmh, you want a bike optimised to deal with yaw angles of around 3°-7°, while the rest of us want a bike designed to tackle yaws of up to 10°-12°.
‘If you look at a WorldTour sprinter coming off a wheel in the last 200m of a race, the effective yaw is extraordinarily low – close to 0°. That’s because they’re going really fast, more than 60kmh, and finishing straights are typically well shielded by barriers and crowds, which serve to block any crosswinds.
‘On the other hand, if you go to the Kona Ironman World Championships, they ride up the Hawaiian coast, with the wind blowing in across the water, so for an age-grouper at Kona the effective yaw angles hit up to the 15° range if it’s gusting. Pros will be going a little bit faster, so they’ll see yaw angles of up to 10° or so – maybe low teens,’ says Yu.

So differences in usual conditions between wheels are smaller than an averaged number over all yaw angles might let us think, as really large differences usually occur north of 10-12 degrees yaw (see HAdron wheels for example). We don't have very large yaw angles in central Europe that often aside from very exposed regions or near the coast.
Last edited by HBike on Mon May 22, 2023 7:03 am, edited 1 time in total.

Lina
Posts: 1266
Joined: Sat Sep 01, 2018 9:09 pm

by Lina

HBike wrote:
Mon May 22, 2023 6:59 am
Lina wrote:
Mon May 22, 2023 1:34 am
Nickldn wrote:
Sun May 21, 2023 11:04 am
Trouble is most studies suggest that unless you're riding the Ironman at Kona you're not going to experience high yaw angles very often.
As if Kona is magically the only windy place on earth. In fact it's not even that windy when speaking about places that have a lot of cyclists. Large parts of Denmark, Belgium, Netherlands, Northern and Eastern France, and UK are all extremely windy. And it's not like those places don't have any cyclists. Just for your own entertainment take a look at the average yearly wind speeds in Copenhagen, Brussels, Amsterdam, and Kona for example. Yeah, suddenly Kona doesn't seem that special.
It is not the wind per se, it is the yaw angle. Very large raw angles are rare. I posted that on another thread, but is still valid

Trek: ‘In the real world 2.5° to 12.5° are the most prevalent yaw angles riders encounter.’
Yu at Specialized adds, ‘For an average cyclist, unless you’re riding in extremely windy conditions, the typical angles are less than 10°.’
This slight difference in results is why one aero bike doesn’t look identical to another. Specialized designed the Venge ViAS based on its vision of the perfect range of yaw, while Trek designed the Madone to fit a different range.
So it seems that if you’re Peter Sagan, driving the peloton along at 50kmh, you want a bike optimised to deal with yaw angles of around 3°-7°, while the rest of us want a bike designed to tackle yaws of up to 10°-12°.
‘If you look at a WorldTour sprinter coming off a wheel in the last 200m of a race, the effective yaw is extraordinarily low – close to 0°. That’s because they’re going really fast, more than 60kmh, and finishing straights are typically well shielded by barriers and crowds, which serve to block any crosswinds.
‘On the other hand, if you go to the Kona Ironman World Championships, they ride up the Hawaiian coast, with the wind blowing in across the water, so for an age-grouper at Kona the effective yaw angles hit up to the 15° range if it’s gusting. Pros will be going a little bit faster, so they’ll see yaw angles of up to 10° or so – maybe low teens,’ says Yu.

So differences in usual conditions between wheels are smaller than an averaged number over all yaw angles might let us think, as really large differences usually occur north of 10-12 degrees yaw (see HAdron wheels for example). We don't have very large yaw angles in central Europe that often aside from very exposed regions or near the coast.
And large parts of Denmark, Belgium, Netherlands, Northern and Western France, and UK all have the exact same conditions as Kona has. Of course it's not the same in central Europe and other more shielded areas. But large parts of cycling's heartlands are in windy areas. And sure, even if you live in an area where winds are common you're not riding with high yaw all the time. But trust me it happens a lot. Acting as if high yaws and wind are only found in Kona is just ignorance.

rudye9mr
Posts: 570
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr

Let's accept that there are places or times of the year where locations may have high yaw angles.

Ytse
Posts: 340
Joined: Thu May 05, 2022 11:53 am

by Ytse

rudye9mr wrote:
Mon May 22, 2023 12:04 pm
Let's accept that there are places or times of the year where locations may have high yaw angles.
Next time you want to chitchat with someone, don't ask about weather in their city, ask about yaw angles. :)
2020 Scott Addict RC / 2023 Specialized Tarmac SL8

txg
Posts: 41
Joined: Fri Feb 05, 2021 9:12 pm

by txg

Two days ago i did a triathlon in central Germany. The bike leg was 40km out and back mostly in northern and southern direction, and according to Garmin wind was 28kph coming from the east.

When going 40kph this equates to a yaw angle of 35 degrees out in the open field. And if we assume that wind speed was about halved in the areas with trees and houses, yaw angle at 14kph wind from the side would still be about 20 degrees. I rode 88mm wheels and it was possible but sometimes pretty challenging to stay in the aerobars all the time. I feel like my sailing background helps a lot with riding deep wheels in higher winds.

And yes, obviously not all days are this windy in central Germany, but winds in the range of 20kph are not exactly rare. Looking at the two other races i did this season wind was 17kph and 22kph. So i'd assume that yaw angles in the range of 10-20 deg are pretty common here, even when going pretty fast at 40kph.

HBike
Posts: 223
Joined: Sun Aug 14, 2022 8:22 pm

by HBike

txg wrote:
Mon May 22, 2023 1:12 pm
Two days ago i did a triathlon in central Germany. The bike leg was 40km out and back mostly in northern and southern direction, and according to Garmin wind was 28kph coming from the east.

When going 40kph this equates to a yaw angle of 35 degrees out in the open field. And if we assume that wind speed was about halved in the areas with trees and houses, yaw angle at 14kph wind from the side would still be about 20 degrees. I rode 88mm wheels and it was possible but sometimes pretty challenging to stay in the aerobars all the time. I feel like my sailing background helps a lot with riding deep wheels in higher winds.

And yes, obviously not all days are this windy in central Germany, but winds in the range of 20kph are not exactly rare. Looking at the two other races i did this season wind was 17kph and 22kph. So i'd assume that yaw angles in the range of 10-20 deg are pretty common here, even when going pretty fast at 40kph.
Statistics tells you larger angle are much less likely, esp. the faster you go. You surely have situations were larger yaws are occuring. But most of the time you are below 10 degrees yaw
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KONA (70% between -10 and +10 degrees)
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Several Ironmens averaged (almost 80% below |10 degrees|)
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So for me, riding for fun and usually not in extreme conditions, I don't need a >60mm wheel, as I am most of the time below 10 degrees were a 40mm to 50mm deep wheel provides a performance close enough not to think about it. If I were seriously racing however, I would of course have several wheel sets to choose from according to situation. That's a no brainer in that case.

rudye9mr
Posts: 570
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr

added 3T and Vision Metron

rudye9mr
Posts: 570
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr

https://altairuniversity.com/wp-content ... 11_web.pdf

*updated first post with link - paper on CFD vs real world

rudye9mr
Posts: 570
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr

– Why HED and not another brand?
– We wanted a smooth, aerodynamic wheel with a rim height of more than 50mm for time trials and moderate elevation gain. HED is a brand that has been producing high-level wheels since 1984 to the point of having filed important patents. In the past, some HED wheels had also been seen on Quick Step timed bikes. In short, we are talking about an established brand that knows how to build high performance wheels.

Astana uses HED wheels

– Only fame or also numbers, data and tests?
– The choice was made with numbers in hand. We took several wheels with the same specifications. Secondly, we cross-referenced the data from the wind tunnel with the tests carried out in the velodrome and on the road. The result is that in crosswind conditions the toroidal profile of the HED rim (patented, ed, details HERE) brought out the best aerodynamic performance. To make things easier, moreover, a friendship with Pepe Navarro Cases, General Manger HED Europe, who did not hesitate to provide adequate support.
Re: Team Astana's take on use of HED wheels

https://news.italy24.press/sports/483327.html

thrilled that HED is being used at the world tour - soft spot for them as i've used and loved them

rudye9mr
Posts: 570
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr


by Weenie


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rudye9mr
Posts: 570
Joined: Wed May 01, 2019 12:01 pm

by rudye9mr

2021 ERC DT Swiss release
The new ERC wheels now feature a wider internal rim width and shallower profiles in a revised aero rim shape, that DT Swiss feels are a better match to the current style of endurance & all-road riding. Leaning into versatility, the ERC family now includes a 45mm deep version that claims to be faster than the slightly deeper original, plus a new lighter, lower-profile 35mm wheelset that’s almost as fast…

DT Swiss ERC carbon Aero road bike wheels, reshaped aerodynamic all-rounder all-road wheelset, rim family

Comparing DT Swiss’ old and new wind tunnel data, we can see that all of their new generation ERC & ARC rims (in red) have reduced drag directly into the wind, with the new VU shapes performing consistently from around -6 to +7° yaw angles. We also see that the difference from the new 35mm to new 45mm is pretty minimal until you get out to more crosswind conditions where not surprisingly, the deeper rim does better.

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.........
With that new (still hooked for greatest security and compatibility) tubeless-ready 22mm internal bead (28.5mm max external), the smallest possible tires for the new ERC wheels is 23mm, and DT rates them for up to 64mm rubber (that’s a whopping 29×2.5″ mountain bike tire!) From an aerodynamics perspective, DT says you’ll get the fastest performance with 28mm tires. And for the best mix of aero performance and comfort, they recommend a 28mm tire up front and a 30mm tire on the rear wheel.......
https://bikerumor.com/dt-swiss-new-erc- ... than-ever/

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