It turns out the Campy Boras are actually quite aero (Tour Magazine latest aero hoops test)

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caddis
Posts: 63
Joined: Sat Mar 03, 2012 2:02 pm

by caddis

I have been testing aerodynamics of my TT-bike trough the summer, and what I have found is that very small changes in position will effect your CdA and you basically can not tell by looking what is the best position for beeing slippery. Offcourse there are some rule of thumb one can use, but eventually you have to test. Supposing your position is absolutely similar with aero and nonaero bike you propably could gain 1kmh, but I would not put my money on it....

reery
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Joined: Sat Jul 30, 2016 9:27 am

by reery

Thanks Damon, that was an exceptional ELI5 explaination.

So basically saving 25 Tour-magazine watts is like riding 1 kph faster @ your usual 32 kph average or 2-3 kph at 40+

Around 3-5% increase in speed with 1-2% accounting to deep section wheels alone.

Better take care of my engine before investing in marginal gains.

by Weenie


Marin
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Location: Vienna Austria

by Marin

reery wrote:
caddis wrote:Don't really understand your question, but NO aerobike in the world will give anyone 45 kph with 235 watts...


The assumption 235 watts at 45 kph is from the Tour magazine.


They also say that if their dummy had an upper body, the Watts would roughly double, but the absolute differences between the wheels would stay the same.

So you're looking at 470W.

caddis
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Joined: Sat Mar 03, 2012 2:02 pm

by caddis

Yeah, maybe if you are cruising along on your bar tops with full winter gear and unzipped your raincoat...:)

alastairb
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Joined: Thu Dec 12, 2013 2:36 pm

by alastairb

dunMisk wrote:I read bought and read the article as wel. I'm quite surprised how little the actual aero effects are. I mean the whole range is from 222 to 239 watts at 45kph. And if you take out the very obvious non-aero wheelsets (C24 / Ksyrium / Hyperion), the difference is only 8 watts between the fastest and the slowest. If I had to conclude from this test, if your going with a decent 30+ mm alu rim and stiff wheel/hub/spoke combination, your set. The difference will only about 4 watts. Spend the rest of your money on spinningclasses / eating well / snug fitting clothes (excluding an aero frameset ofcourse).


Interesting to hear; I'm currently running a set of Fulcrum Racing Zeros and toying with the idea of upgrading to a set of Fulcrum Speed 40 Clinchers or Mavic Cosmic Pro Clinchers...am I seriously considering an investment that will not give a tangible benefit!

bm0p700f
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by bm0p700f

The tour watts are not real watts to ride at 30 mph i have to be producing over 400w. Therefore if i rode aero wheels and jon aero wheels at this speed the difference will be much bigger.

Aero gains are small and flappy clothing and bad position will negate them but if your clothing and position are as good as they can be then each aero gain, wheels, tyres, bars frame all have an additive effect. By themselves each effect is small. added together the effect is bigger still small.

Even at low yaw angles the deeper wheels still have a marginal gain. Given the extra weight is not slowing you at all there still is no point in the shallower wheels, except for the alloy ones they are cheaper.

So those 40mm fulcrjms are pointless. The flo30's would be just as good and cost you less. The 31mm deep wheels i built would fair nearly as well. Deeper wheels such as 50 to 60 mm depth will give a extra gain it maybe small but it is real. These half way house wheels are just marketing.

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F45
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by F45

It's all about the safety factor. At 30-40mm, a 450 gram aluminum rim is at the edge of its design. A 450 gram carbon rim is well within its. A flow 30 is 600 grams. :shock:

commendatore
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Joined: Mon Dec 30, 2013 1:51 am

by commendatore

Flo 30 rim weighs much less than 600 grams. I have an example here that weighed in at 518


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F45
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by F45

Well they are currently listing it as 570 +/- 20g so if one is that light then something is up.

MariusRO
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Joined: Sun Aug 19, 2018 10:40 am

by MariusRO

What do you think about the momentum created by larger aero wheels like zipp808 Hed H3 and so on? How does this contributes to keeping a higher speed ?

ome rodriguez
Posts: 333
Joined: Fri Feb 24, 2006 9:16 am

by ome rodriguez

Try riding on a trainer with bora ultra 50 and fulcrum speed 55 and you’ll notice the rim bed crooked where the spokes pull.

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