"Lightness" vs "Aeroness" UPDATED 10/2023

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mrlobber
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by mrlobber

Lina wrote:
Mon Mar 01, 2021 12:10 pm
1) The speed doesn't matter as long as it's something that can be achieved with a bike unless you're trying to do something like optimizing gear for a record attempts. The aerodynamics don't dramatically change between 30 and 50 km/h. Obviously the differences are smaller in lower speeds but does that really matter, the order of the bikes won't change.
It doesn't, but higher speeds inflate the wattage differences in the charts. Just like you could hear from some (ordinary, not TT) helmet manufacturers that you save seconds versus other helmets at even more ridiculous speeds: 50kmh, and above. Whenever I see a manufacturer putting the test speeds up, I have to question why... with the most probable answer being - yes, the differences are there, but actually too small to make our product stand out from the others. And again, what's that secret sauce for QR for the bike to remain like constant drag almost through all yaw angles tested? I cannot recall any other wind tunnel tests where a frame would have behaved that way. One of the reasons (just my guess) would be that they tested bike-only whereas most of the other tests we've seen are done with a mannequin or at least "rider legs".

As for yaw angles, only 5% you go outside of 10deg, and ~75% is spent within 5deg interval (unless you ride Kona), and that's with lower speeds than those 45+ kph (higher speed decreases the effective yaw angle) https://www.slowtwitch.com/Tech/Real_Wo ... _5844.html

Anyway, kudos to QR bringing out a nicely performing aero disc bike for the price which severely undercuts all of the competition.
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Lina
Posts: 1060
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by Lina

mrlobber wrote:
Mon Mar 01, 2021 12:49 pm
As for yaw angles, only 5% you go outside of 10deg, and ~75% is spent within 5deg interval (unless you ride Kona), and that's with lower speeds than those 45+ kph (higher speed decreases the effective yaw angle) https://www.slowtwitch.com/Tech/Real_Wo ... _5844.html
There are plenty of other places outside of Kona that has constant winds. And obviously you're not always going in a direction where the yaw is notable. Plenty of time is spent at head or tail wind, or somewhere between them and a cross wind. And while you may not spend a lot of time at larger yaws overall there are rides that are done at large yaws almost entirely if you live in a place with constant winds. I love it when people who've never even seen an ocean come and tell me how anything past -/+5 degree yaws hardly ever exist when I encounter them on practically every single ride.

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FlatlandClimber
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by FlatlandClimber

Singular wrote:
Mon Mar 01, 2021 11:59 am
FlatlandClimber wrote:
Mon Mar 01, 2021 11:18 am
I will not discus all of this again.
Just two points:
- the "fastest" set up is not the one that crosses the line first, but the one that is the most efficient for a given course. Efficiency is fast. Van Aert and VDP beat most pros on a course like that even on a early 2000s round tube bike, with box section wheels. But the margin they win by is smaller than with a faster set up. The win was by margins of a second, so Van Aert could have done better with slightly faster set up (at least that's what the science says)-
- rotational weight is probably the most overvalued thing in cycling ever! Rather look into aerodynamics of a rotating object, that is A LOT MORE important than its weight. Aero savings on your wheels actually do "more" than on your frame, while the same cannot be said for weight savings (downhill force just doesn't care ...)
Here's the really interesting question you need to ask; So, why do they make these choices?
According to several teams (see the GCN meets pro mechanics videos for example), because they like it better.
Many of the riders have ridden shallow wheels, tubular tires and climbing frames all their lives, so getting used to it is certainly a point.
Riders that have done more geekery (see TTists, Hour Record holders etc), usually ride deeper wheels and more aero bars than sprinters or GCers. Alex Dowsette won stage 8 of the 2020 Giro on 60mm rims on a long solo break-away, although the stage was classified as "hilly".
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spartacus
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by spartacus

mrlobber wrote:
Mon Mar 01, 2021 10:14 am
Robius wrote:
Sun Feb 28, 2021 9:52 pm
Direct link to the whitepaper: https://cdn.shopify.com/s/files/1/0006/ ... 1614203184

Long story short, buy aero water bottles for your Canyon Aeroad. :lol:
My 2 problems with this QR testing are the following:

1) it has been done at 30mph, thus 46kmh. Who (except pros in races) rides his/her bike solo at those speeds?? Even TT bikes usually are tested at 45 kmh. This means that the wattage differences at "more realistic" speeds are quite a bit lower.
2) take note at yaw angles. If you're doing 45+ kmh, don't tell me you're really facing anything outside of -5...+5 range except extreme crosswind circumstances.

Third, more of a "traditional" (whenever aero testing is involved) note: that QR bike looks totally similar to all recent disc semi-aero bikes. What's the "secret sauce" which suddenly allows them outperforming all others? If the answer is "fatter downtube", please keep me from LOLing.

P.S. I agree on the negative bottle effect on narrow-sized downtube bikes - this has already been exposed since 2016, and I've told it here as well, that, for instance, Felt always avoided the question how their otherwise-magnificently-aero 2nd gen AR rim brake bike performed with bottles. Guess why :twisted:
1. I hate this argument so much. My average speed isn't 30 but I reach and exceed 30 many times per ride. Yesterday I got a Strava trophy where my segment speed was 30 and I'm not pro or even very fast.

2. The wind blows around and changes, I can feel it doing it especially with deep wheels, not "extreme" to me it is "normal"

spartacus
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by spartacus

Singular wrote:
Mon Mar 01, 2021 11:59 am
FlatlandClimber wrote:
Mon Mar 01, 2021 11:18 am
I will not discus all of this again.
Just two points:
- the "fastest" set up is not the one that crosses the line first, but the one that is the most efficient for a given course. Efficiency is fast. Van Aert and VDP beat most pros on a course like that even on a early 2000s round tube bike, with box section wheels. But the margin they win by is smaller than with a faster set up. The win was by margins of a second, so Van Aert could have done better with slightly faster set up (at least that's what the science says)-
- rotational weight is probably the most overvalued thing in cycling ever! Rather look into aerodynamics of a rotating object, that is A LOT MORE important than its weight. Aero savings on your wheels actually do "more" than on your frame, while the same cannot be said for weight savings (downhill force just doesn't care ...)
Here's the really interesting question you need to ask; So, why do they make these choices?
I'd bet $100 the shallower wheels are just easier to handle in a bunch and require less vigilance when you're exhausted and that's the main reason they pick them. Also benefit of being slightly lighter aka "reactive" feeling.

FlatlandClimber
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by FlatlandClimber

Should only be "reactive feeling" though. An aero wheel accelerates faster at higher speeds, while a lighter wheel will accelerate better from a stand still or very low speeds...
The point you make about handling is valid, although I can't really fathom that they really struggle to control a bike with deep wheels, when they can control a bike at 100kph while sitting on the top tube...
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*weights are race ready, size 58/L.
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spartacus
Posts: 1049
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by spartacus

FlatlandClimber wrote:
Mon Mar 01, 2021 7:01 pm
Should only be "reactive feeling" though. An aero wheel accelerates faster at higher speeds, while a lighter wheel will accelerate better from a stand still or very low speeds...
The point you make about handling is valid, although I can't really fathom that they really struggle to control a bike with deep wheels, when they can control a bike at 100kph while sitting on the top tube...
Someone can chime in if I'm off base here but it seems like no matter how good of a bike handler you are, a strong sudden gust can easily blow you a couple inches when you have deep wheels. In a group of 100 really tired dudes packed in super close it seems like this has to be a consideration, no? That said yeah you'd think maybe if you plan on being in a break all day you'd go with the deep wheels but obviously there's a reason some of them don't and I can only speculate handling and reactiveness feeling is why because like you said the math suggests they'd save watts with different wheels.

M4lukz
Posts: 195
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by M4lukz

spartacus wrote:
Mon Mar 01, 2021 7:18 pm
FlatlandClimber wrote:
Mon Mar 01, 2021 7:01 pm
Should only be "reactive feeling" though. An aero wheel accelerates faster at higher speeds, while a lighter wheel will accelerate better from a stand still or very low speeds...
The point you make about handling is valid, although I can't really fathom that they really struggle to control a bike with deep wheels, when they can control a bike at 100kph while sitting on the top tube...
Someone can chime in if I'm off base here but it seems like no matter how good of a bike handler you are, a strong sudden gust can easily blow you a couple inches when you have deep wheels. In a group of 100 really tired dudes packed in super close it seems like this has to be a consideration, no? That said yeah you'd think maybe if you plan on being in a break all day you'd go with the deep wheels but obviously there's a reason some of them don't and I can only speculate handling and reactiveness feeling is why because like you said the math suggests they'd save watts with different wheels.
If I remember correctly, Froome had the horrible crash on his TT bike, while doing the reckon, because he was caught offguard by a sudden gust of wind

wolflikeme
Posts: 245
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Location: USA

by wolflikeme

hannawald wrote:
Wed Jan 27, 2021 10:46 pm
What may be the reason that some pros are still riding standard roundish bars rather than aero bars even though they have a choice? For example K Force bars rather than Vision Metron integrated bars (one of the stiffest and most aero bars)..

I don't get it if we know that aero advantage on bars is one of the highest..

https://www.cyclingnews.com/features/lu ... 4-gallery/
I thought that this was a durability choice. If you crash with an alu bar you can still pick up your bike and go. If you crash on a carbon bar you have no idea if it's cracked or not.

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mrlobber
Posts: 1928
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by mrlobber

spartacus wrote:
Mon Mar 01, 2021 4:22 pm
1. I hate this argument so much. My average speed isn't 30 but I reach and exceed 30 many times per ride. Yesterday I got a Strava trophy where my segment speed was 30 and I'm not pro or even very fast.
Well, I've got a fair share of KOM's at close to 50 kph as well, that changes what? That 46 kph are "normal speeds" for road bikes? :D

Although, I admit I was wrong thinking that the industry tests the bikes at 40 kph; it turns out, for instance that Tour are doing 45 after all, however, with the rider legs present (and in fact including a 0.75liter bottle as well, see https://www.tour-magazin.de/service/so_ ... 43957.html), which QR does not. And thus, it's still ironic that QR suggests that bikes should be tested with bottles on while ignoring the fact that rider also should be present :D, and makes me question their approach that suddenly they somehow have like the fastest bike out there as if the industry (S5 Disc, SL7, the new Aeroad (or old, can't really figure out which one they tested)) have been sleeping for the past 5 years.

Again, I stress that I applaud the effort as the bike certainly isn't slow, and I like the price point at which it is introduced even more.
spartacus wrote:
Mon Mar 01, 2021 4:22 pm
2. The wind blows around and changes, I can feel it doing it especially with deep wheels, not "extreme" to me it is "normal"
Can't argue with that as what you posted is entirely subjective. Yaw angle distribution in a large enough sample, however, is not.
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Singular
Posts: 537
Joined: Mon Jul 27, 2020 8:59 am

by Singular

Well, I'm more often than not supporting the idea of testing at 45kmh. Why? Because it is the relevant speed for racing. What is the speed of a breakaway, a break, a bridging attempt, an attack or the front of a normal four-corner criterium? Pretty close to 45, that's for sure.

If it is relevant to you what the power requirement is for pushing a bike through the air, it should of course be measured at a speed where it reasonable to be worried about it. Hell, I'm cruising around the countryside at 30kmh too (and a lot more hours than at 45, that's for sure! :) ) but it is not relevant for me to know drag figures for that kind of application.

As an added bonus, it does (for good and bad) amplify numbers and differences.

FlatlandClimber
Posts: 2491
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by FlatlandClimber

I just stumbled upon the releases of several Hubt wheels, who interestingly enough have released wind tunnel results along side.
What makes these worthwhile, is that Hunt does not win all categories or anything.
Test from a year ago:
https://cyclingtips.com/2020/01/hunt-re ... ke-wheels/
Current test: https://cyclingtips.com/2021/02/hunt-ex ... 0-version/
They are performed with different tires, mind you.

Interesting how well ENVEs and Rovals perform.
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*weights are race ready, size 58/L.
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spartacus
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by spartacus

Looked like there were a lot of 40mm wheels at strade bianche.

FlatlandClimber
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Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

...Looks like the race was won on the most aero frame currently available and 60mm wheels...
What they choose means little to nothing. VDP chose the most aero option his sponsors allowed for and the runner up Alaphillpe and the second runner up Bernal chose the least aero option their respective sponsors allowed (not choosing the word "lightest", because the a SL7 with Rapide Wheels in Ala's size would have been 6.8kg anyway. He just rides shallow wheels no matter what).
Cervelo P5 Disc (2021) 9.1kg
Factor Ostro Gravel (2023) 8.0kg
S-Works SL8 (2023) 6.3kg

*weights are race ready, size 58/L.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT, Crux, Aethos, SL7

by Weenie


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FlatlandClimber
Posts: 2491
Joined: Tue Mar 31, 2020 3:37 pm

by FlatlandClimber

New Results

Image

Sizes are a little all over the place, with 54 and 56...
The Aeroad has 60mm wheels and the Scott has super shallow wheels... not the best comparison.
Cervelo P5 Disc (2021) 9.1kg
Factor Ostro Gravel (2023) 8.0kg
S-Works SL8 (2023) 6.3kg

*weights are race ready, size 58/L.
Sold: Venge, S5 Disc, Roubaix Team, Open WI.DE, Émonda, Shiv TT, Crux, Aethos, SL7

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