Aero Gravel question / perspective

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Alolympic
Posts: 12
Joined: Tue Jun 19, 2018 11:23 pm

by Alolympic

There will be an aero benefit, whether it is enough is a very personal thing.
To me, from what I have read in various channels, something like 80% of aero drag is the rider (their position, clothing, helmet etc.) then 20% is the bike frame, tyres, components, drivertrain etc.
How much more aero will an aero optimised gravel race frame be compared to say, a Crux. Maybe 10% tops?
But that isn't 10% improvement of the total bike - as it is just the frame, and the intergrated cockpit I guess. So, let's be more realistic and say it 7% more aero. After all, the tyres, wheels and drivertrain will be equal.
That would make it very roughly - a 7% improvement of the total 20% that is the bike. Which equates to 1.4% improvement of the total system.
If the bike is better suited to you, you like it more, it will inspire you are to ride more, great.
And if a 1.4% aero improvement feels worthwhile to you, go for it.

Big caveat that this is all rough approximation in terms of numbers...

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

by FlatlandClimber

Aerowheels is a topic I am still a little lost about. Some manufacturers (Swiss Side, Hunt) claim there is an advantage to be had, even when using 40c tires on a ~30mm external rim, while ENVE states, the Aero Advantage of their wheels is lost when going beyond a 33mm tire.

I find it interesting that Factor/ BlackInc equip their Aero gravel bike offering with very shallow 34mm deep wheels, and still claim an aero advantage.

The Dicut 45/ 40 and Nextie look like an interesting option, too, but apparently no one has ever aero tested them. Should we just go stupid low weight with textile spokes? Or is there a sizeable aero advantage to be had?
SwissSide say 1.8W between a 42mm and 25mm deep wheel. But then again, they are selling a product.
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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spartacus
Posts: 1049
Joined: Mon Apr 04, 2011 6:53 pm

by spartacus

FlatlandClimber wrote:
Fri Jan 27, 2023 4:52 pm
Aerowheels is a topic I am still a little lost about. Some manufacturers (Swiss Side, Hunt) claim there is an advantage to be had, even when using 40c tires on a ~30mm external rim, while ENVE states, the Aero Advantage of their wheels is lost when going beyond a 33mm tire.

I find it interesting that Factor/ BlackInc equip their Aero gravel bike offering with very shallow 34mm deep wheels, and still claim an aero advantage.

The Dicut 45/ 40 and Nextie look like an interesting option, too, but apparently no one has ever aero tested them. Should we just go stupid low weight with textile spokes? Or is there a sizeable aero advantage to be had?
SwissSide say 1.8W between a 42mm and 25mm deep wheel. But then again, they are selling a product.
When the tire gets wider, the air foil needs to get longer (rim deeper) to keep the airflow attached; it seems that gravel tires are wide enough that this is impractical to accomplish well.

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