Professional riders are riding compact cranks through the big hills and largely coasting down the descents in the 50 ring. So I attempted to do that with my 52-36 and found no improvement in my speed. If you can accelerate up to speed as you cross over the top of a hill in a compact 50-34 you cannot improve your descending speed with a 52.

So I have to apologize to Flunky and accept that he was actually correct about descending speed has to do with aerodynamics rather than pedal power.

On Friday, October 27, 2023 at 5:04:13 PM UTC+1, Tom Kunich wrote:
> Professional riders are riding compact cranks through the big hills and largely coasting down the descents in the 50 ring. So I attempted to do that with my 52-36 and found no improvement in my speed. If you can accelerate up to speed as you cross over the top of a hill in a compact 50-34 you cannot improve your descending speed with a 52.
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> So I have to apologize to Flunky and accept that he was actually correct about descending speed has to do with aerodynamics rather than pedal power.
>
It does raise the question of what can one assume is Cd (aero coefficient) of cyclist:
1. On the drops with a flat back in skintight gear?
2. Semi-sporting position, back say at 45 degrees, say in a tracksuit?
3. Upright, back at 80 degrees or so, in street clothes, as on a utility bike?
>
On my rather rough lanes and small country roads, the road surface has a definite influence on how fast one can go downhill, which in turns depends on tyre size and inflation. I have no problem leaving the drop bar brigade on thin high-pressure tyres behind on the downhill, those who even try to keep up with me arrive at the T-junction at the bottom of the hill where I set my personal truck assisted ton-up record with whites line on their faces and don't try it again. But I ride on 60mm wide Big Apples inflated to only 2 Bar or a fraction over, so that I think nothing of riding through a pothole at 50kph. But just 5kph faster and you run the risk of a sudden decompression and a face plant at exactly the same pothole.
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Andre Jute
Flunky who?
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