Aero/Gains Thread

Thomas. PLease. said:
H10/22 for me today, managed 19:55, my first sub 20. Season aim was a short 20 so very pleased to have achieved that so soon in the year. Was not ideal conditions 7th rider off at 5 degrees celsius. So hopefully once my position is sorted a little more, and I've found some more watts I can go faster.
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super quick - well done!
 
Cannot understand how you boys get so fast.
5w/kg got me a 22:44 the other week! Got a selfish **** in a lorry overtake me on a blind bend then held me up for 45 seconds. So even at that, those sort of watts only good for long 21's. And it's not me being super non aero, the guys all beating me are pushing out much higher watts and are nowhere near the 20 mark.
 
I want to say I'm weak at TTing because I'm a climber's build but Nairo Quintana is pretty handy at TTing and he's the same height/weight as me.:(

Going to the velodrome tonight to do a 20min test on the TT bike and see where my zones are at. Since I failed miserably trying to run a fast marathon, my new goal is to try and improve my RP TT time.
 
xdcx as you know 2 Main factors of resistance.

Aero

Rolling/Friction Losses

Obviously first one you can do a chunk about, but the second one will have limited scope if you have poor surfaces. What's the pressure like generally up your way as this could be a factor too.
 
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a lot of folk up here play the old "it's because they TT on good surface and on dual carriageways and get benefit from lots of traffic". I know that to be the case with some of the courses down there but not every course like people up here try to make out. Our surfaces are horrific, I can confirm that much.

Typical 1010hPa +
It's never been below 1018 for a TT yet this year.
I can remember once last year where it was 990ish.
 
I only ask as a stemmed thought from xdcx's post, if I recall he's quite short & light?, so figured that even though his w/kg will blow most out of the water with similar CdA to that of a larger rider on a flat course it wouldn't bear quite so much influence.

W/CdA isn't something I'm familiar with but am familiar with the principle that the faster you are moving then the increase in work required to accelerate is a diminishing return compared to that at a lower speed. Is this similar?
 
xdcx said:
a lot of folk up here play the old "it's because they TT on good surface and on dual carriageways and get benefit from lots of traffic". I know that to be the case with some of the courses down there but not every course like people up here try to make out. Our surfaces are horrific, I can confirm that much.

Typical 1010hPa +
It's never been below 1018 for a TT yet this year.
I can remember once last year where it was 990ish.
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We all know the quick courses, but only way to really be sure is to ride the quick ones to see how you come out. Sunday on the A3 there were some 48s laid down, and yet my quickest ride on that course was a 54:45 last year which would have beaten quite a few people on Sunday. Conditions really do play a big part with one of my mates putting out the same power but going over a minute slower than his time last year.
 
BennyC said:
I only ask as a stemmed thought from xdcx's post, if I recall he's quite short & light?, so figured that even though his w/kg will blow most out of the water with similar CdA to that of a larger rider on a flat course it wouldn't bear quite so much influence.

W/CdA isn't something I'm familiar with but am familiar with the principle that the faster you are moving then the increase in work required to accelerate is a diminishing return compared to that at a lower speed. Is this similar?
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This is quite broad brush but fairly helpful: https://twitter.com/xavierdisley/status/538269709939253248?lang=en

Assuming a perfectly flat TT course and two riders doing 300w, one is 70kg with a CdA of 0.2 and the other is 80kg with a CdA of 0.18. The lighter rider will obviously have a higher w/kg, but as his aero position is comparatively worse he will go slower. You can compare their w/CdA by dividing power by their CdA value:

A: 300/0.2 = 1500
B: 300/0.18 = 1667

It's mainly a useful metric when you're trying to trade power vs aerodynamics. Rider A for example could squish himself into a 0.17 CdA but can now only put out 280w in that position. However, divide power by CdA and you get 1647, which is a significant improvement over his original position despite making less power.

As a benchmark, Wiggins' hour record was reckoned to require a w/CdA of ~2,200.
 
I think front end of my body would seriously struggle to be much narrower. I can get a touch lower I feel but I am way narrower than everyone I see in pictures.
60kg and at 308watts now with the goal of 320ish come national 10, on paper, that should result in a serious time. I am at disadvantage of only running 40mm wheels with not ideal tyres and my skinsuit is bottom end Impsport only. It's annoying knowing I could be quite a bit faster with the gear but I'll just need to smash out as is with a few aero position "advances" over the next couple weeks and see what it nets me.
 
Thomas. PLease. said:
Lower is a lot more aero than narrower
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I agree with you (and was about to type something similar) but I think the way you've worded it could be misunderstood. Lower and narrower are equally as aero as each other: if you tuck 1cm lower you should get the same overall result as becoming 1cm narrower.
There's nothing magic about being lower which makes it more aero than being narrower, it's just that humans are naturally taller than they are wide so there's more scope for becoming lower than there is for becoming narrower. As long as you're not obese, there probably isnt much scope at all for becoming narrower - you might get some improvements out of moving your arm rests about but the bone structure in your shoulders and hips are going to limit how much you can do. It's much more effective to reduce frontal area by reducing height.
 
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