Weight weenies vs watt weenies...

[HBike]

Don't know if posted here before.
https://www.cyclingnews.com/features/wi ... e-fastest/
For an aero geek like me, very underwhelming differences. Basically nothing in it (weight saving gains are that low too though).

German magazin Tour tests with bike and dummy, so including the movement of legs etc. to my knowledge.
There you see a difference of up to 15W compared to stock wheels when replaced with Zipp 404. SwissSide tests showed that the best wheel/tire combi saved 5W at 30km/h, 11W at 37.5km.h and 20W at 45km/h. 

Overall a good racing bike (Giant TCR, Merida Sculture, Cervelo R5) is about 20W slower than an aero bike, an endurance bike loses 30W - 40W and a gravel bike around 90W compared to an aero bike at 45/km/h.

[FlatlandClimber]

90W aero drag more on a gravel bike sounds extremely high. Gravel bikes are way too diverse to really put a number on that. I have an Aethos and a Crux. I guess the aero difference is 10W and all of that is in 20mm wider bars and the wider front tire.

Endurance bikes are not necessarily slower either. The position is not taken into account at Tour Mag, with their dummy not having an upper body.
Specilaized claimed the Roubaix was more aero than the SL6, and just looking at the frame, I kinda believe that.

Difficult to find absolutes here. Swiss Side also only has like 5W difference at 45kph between 80/Disc vs 50/50.
i really don't believe that figure, with Aerocoach for example claiming much larger differences.

In this test however, all the wheels were within 12mm of each other in depth, so it is likely the differences aren't huge.

[ghostinthemachine]

90W aero drag more on a gravel bike sounds extremely high.

It's likely for a rider sat bolt upright in a "standard" gravel bike position. So the vast majority is likely to be extra rider drag.

[Andrew69]

Don't know if posted here before.
https://www.cyclingnews.com/features/wi ... e-fastest/
For an aero geek like me, very underwhelming differences. Basically nothing in it (weight saving gains are that low too though).

A test w/o rotational drag, and even worse, w/o a bike? ...

Apparently not rotating, but fitted with a 25mm Schwalbe Tire and on a standardized bike. No rider.

They were rotating
"We tested with an airspeed of 45km/h (27.96mph). This is representative of professional peloton speeds. Naturally, we ensured the wheels were spinning at the same speed, because the behaviour of airflow over the rim and spokes is very different on a static wheel, and not at all representative of the real world."

[HBike]

90W aero drag more on a gravel bike sounds extremely high. Gravel bikes are way too diverse to really put a number on that. I have an Aethos and a Crux. I guess the aero difference is 10W and all of that is in 20mm wider bars and the wider front tire.

Endurance bikes are not necessarily slower either. The position is not taken into account at Tour Mag, with their dummy not having an upper body.
Specilaized claimed the Roubaix was more aero than the SL6, and just looking at the frame, I kinda believe that.

Difficult to find absolutes here. Swiss Side also only has like 5W difference at 45kph between 80/Disc vs 50/50.
i really don't believe that figure, with Aerocoach for example claiming much larger differences.

In this test however, all the wheels were within 12mm of each other in depth, so it is likely the differences aren't huge.

These are average values. We are looking at pretty high speeds on average and compared to the bes aero road bikes in those test and you are right for sure that they are diverse.
If you fit 28mm wheels, decrease spacers, use internal routing, aerobar and aerowheels etc. you will result in lower differences for sure. But then it is not for gravel. 40mm to 50mm wheels with larger profile, flared non-aero bars, 1by with huge 50-52 cassettes, relaxed position, mounting points etc. makes the 90 W compared to a Cervelo S5 at that speed plausible.

[FlatlandClimber]

Yeah, but I gotta say, taking the position into account for "which bike is faster" is not a great approach.
My Crux has minimal more stack than my roadie, 20mm wider handlebars, equally deep wheels, wider tires (so a little slower here and there) BUT I run aero bars on it.
So for all the technical stuff I am more upright, but I am slower here anyway. On the fast stuff, I am on the skies, which is likely more aero than my position on the roadie anyway...

[HBike]

Yeah, but I gotta say, taking the position into account for "which bike is faster" is not a great approach.
My Crux has minimal more stack than my roadie, 20mm wider handlebars, equally deep wheels, wider tires (so a little slower here and there) BUT I run aero bars on it.
So for all the technical stuff I am more upright, but I am slower here anyway. On the fast stuff, I am on the skies, which is likely more aero than my position on the roadie anyway...

Some bike distributers provide nice versatile configurations, Specialized is one of them in my opinion. I also like Wilier (Rave) in that respect.

[blaugrana]

Don't know if posted here before.
https://www.cyclingnews.com/features/wi ... e-fastest/
For an aero geek like me, very underwhelming differences. Basically nothing in it (weight saving gains are that low too though).

A test w/o rotational drag, and even worse, w/o a bike? ...

Apparently not rotating, but fitted with a 25mm Schwalbe Tire and on a standardized bike. No rider.

They were rotating
"We tested with an airspeed of 45km/h (27.96mph). This is representative of professional peloton speeds. Naturally, we ensured the wheels were spinning at the same speed, because the behaviour of airflow over the rim and spokes is very different on a static wheel, and not at all representative of the real world."

Most tests are done with rotating wheels (otherwise it's not worth even bothering), but that doesn't mean they measure rotational drag. There is a motor powering the wheels, but the amount of power that this motor uses to overcome the air drag that's slowing it down rotationally is generally not measured, typically only the horizontal force that the wind applies to the system is measured.

[spartan]

tour mag test on 60mm wheels most wheels were with 1 watt. the shimano c60 was within 05 watt of dtswiss.

also why they include wheels with a front depth of 50+ vs the 60+ . i don't trust their results.

scroll down to the wheel section. wide wheels tested worse e.g zipp 454 nsw
https://www.cyclesetforme.fr/performanc ... orld-tour/

[HBike]

tour mag test on 60mm wheels most wheels were with 1 watt. the shimano c60 was within 05 watt of dtswiss.

also why they include wheels with a front depth of 50+ vs the 60+ . i don't trust their results.

scroll down to the wheel section. wide wheels tested worse e.g zipp 454 nsw
https://www.cyclesetforme.fr/performanc ... orld-tour/

? Tests seem legit. I don't see your point at all. Why shouldn't they compare different depths, resulting in different lift coefficients in crosswind and flow separation points.

[spartan]

why rank a wheel with a 52mm front with one that is 62 ? diff class category. tour tested wheels with depth max 50. dtswiss finished first again but the rest were very close. less than 1 watt. only dog was the zipp 303.

also dura ace c60 scores very close to dtswiss with tour mag test but 2 watts slower with cyclingnews ?

tour mag test on 60mm wheels most wheels were with 1 watt. the shimano c60 was within 05 watt of dtswiss.

also why they include wheels with a front depth of 50+ vs the 60+ . i don't trust their results.

scroll down to the wheel section. wide wheels tested worse e.g zipp 454 nsw
https://www.cyclesetforme.fr/performanc ... orld-tour/

? Tests seem legit. I don't see your point at all. Why shouldn't they compare different depths, resulting in different lift coefficients in crosswind and flow separation points.

[justkeepedaling]

why rank a wheel with a 52mm front with one that is 62 ? diff class category. tour tested wheels with depth max 50. dtswiss finished first again but the rest were very close. less than 1 watt. only dog was the zipp 303.

also dura ace c60 scores very close to dtswiss with tour mag test but 2 watts slower with cyclingnews ?

tour mag test on 60mm wheels most wheels were with 1 watt. the shimano c60 was within 05 watt of dtswiss.

also why they include wheels with a front depth of 50+ vs the 60+ . i don't trust their results.

scroll down to the wheel section. wide wheels tested worse e.g zipp 454 nsw
https://www.cyclesetforme.fr/performanc ... orld-tour/

? Tests seem legit. I don't see your point at all. Why shouldn't they compare different depths, resulting in different lift coefficients in crosswind and flow separation points.

Cyclingnews straight averaged all yaw results. That's not how it should be done. Interestingly, the Reserve wheels tested "poorly" but supposedly the new ones are supposedly about 4-5 Watts faster. That puts them as being competitive with the fastest

[spartan]

well look at how giant compared their new cadex 50 ultra.
https://www.cadex-cycling.com/us/testing-50-ultra-disc

so the roval/dtswiss/enve all within the margin of error.

we need to wait for bicyclerolling resistance to test the cadex tubeless tires.

[cajer]

When comparing a disc vs non disc rear wheel, you have to account for rotational losses and basically no test does that (1/4 of translational losses). Also talking to some specialized engineers they saw some significant gains going from 24-18 front spokes.

[HBike]

why rank a wheel with a 52mm front with one that is 62 ? diff class category. tour tested wheels with depth max 50. dtswiss finished first again but the rest were very close. less than 1 watt. only dog was the zipp 303.

also dura ace c60 scores very close to dtswiss with tour mag test but 2 watts slower with cyclingnews ?

tour mag test on 60mm wheels most wheels were with 1 watt. the shimano c60 was within 05 watt of dtswiss.

also why they include wheels with a front depth of 50+ vs the 60+ . i don't trust their results.

scroll down to the wheel section. wide wheels tested worse e.g zipp 454 nsw
https://www.cyclesetforme.fr/performanc ... orld-tour/

? Tests seem legit. I don't see your point at all. Why shouldn't they compare different depths, resulting in different lift coefficients in crosswind and flow separation points.

Perfectly possible.
- Different Spokes
- Different hubs
- Different wind tunnel cross section and therefore confinement effects
- Different inflow turbulence intensity levels
- Different boundary layer development before interacting with the bike (e.g. due to surface roughness or postion of wheels further up- or downstream)
- Different wheel/mounting/frame configurations

This just shows that for some wheels differences are negligible. It requires more fundamental differences to make a significant impact (e.g. no vs. aero rim, surface dimples vs. no dimples, etc.). Normally one needs to do a sensitivity analysis to test robustness of the results. Most testers don't have the time to do all this.
We can do that at a university, but that is usually not done for a magazine.

Small differences matter though. I just watched the time trial of the European championship, where Küng and Bisegger - 0.34 s difference in the end.