TT £'s per Watt
mclarent
Posts: 784
I saw somebody ask a question on what was the contribution of TT kit to performance. Tri Plus magazine (which I got free before you ask - I hate running and my swimming is more akin to drowning!) has an interview with Mr Boardman where he covers this, so thought I'd share! Hope it's useful to some!
First point is that the cheapest way to achieve gains is through correct body position and aerodynamics - 80% of the frontal exposure area is you, not the bike. His position recommendation is to get as horizontal as possible, not leaning too far forward and making sure you're comfortable, tucking your elbows in "exactly the right amount". Elbows should line up with legs, so that they make the hole in the air and your legs just move through it.
For equipment he reckons:
1. Aerodynamic helmet gives you savings from £5.40 per watt at 40km/h
2. Aero wheels from £40 per watt saved compared to 32 spoke wheels
3. Time trial frames are worth 1.3km/h (-20 watts drag) at 40 km/h
4. Clip on aero bars are £2 per watt at 40 km/h
First point is that the cheapest way to achieve gains is through correct body position and aerodynamics - 80% of the frontal exposure area is you, not the bike. His position recommendation is to get as horizontal as possible, not leaning too far forward and making sure you're comfortable, tucking your elbows in "exactly the right amount". Elbows should line up with legs, so that they make the hole in the air and your legs just move through it.
For equipment he reckons:
1. Aerodynamic helmet gives you savings from £5.40 per watt at 40km/h
2. Aero wheels from £40 per watt saved compared to 32 spoke wheels
3. Time trial frames are worth 1.3km/h (-20 watts drag) at 40 km/h
4. Clip on aero bars are £2 per watt at 40 km/h
"And the Lord said unto Cain, 'where is Abel thy brother?' And he said, 'I know not: I dropped him on the climb up to the motorway bridge'."
- eccolafilosofiadelpedale
- eccolafilosofiadelpedale
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Comments
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Why does number 3 go from a £s per watt to km/h saved? It's not easy to compare the different solutions.
It also assumes that more expensive kit is always better which is clearly not the case and just encourages spending your way to a faster time.
Can't believe that aero frames are worth 20watts. For me that would be 8%, so my 58min 25 would go down to a 53.30!
I appreciate that these are not your thoughts so thanks for the post
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he must have a blog you can complain to?
To be fair to him I have pretty selectively edited the article!!"And the Lord said unto Cain, 'where is Abel thy brother?' And he said, 'I know not: I dropped him on the climb up to the motorway bridge'."
- eccolafilosofiadelpedale0 -
Power and speed are not linearly related. It is a cubic relationship. Your speed improvement with 20 watts extra* would be of the order 90 seconds or ~ 2.5%.inseine wrote:Can't believe that aero frames are worth 20watts. For me that would be 8%, so my 58min 25 would go down to a 53.30!
Given you are doing a 58 min 25 with ~ 250 watts, you are reasonably slippery already I'd say. Every little bit helps.
* it is really annoying when aero savings are quoted in terms of watts saved - it is pretty meaningless, since we don't go out there and suddenly ride at 20 watts less for the same speed. They really should be quoted in terms of a reduction in CdA.0
