Poll: What's your 40K TT / FTP ratio (was FTP)

[yzfrr11]

JBV is obviously a highly experienced timetrialist. Along those lines, my feeling is that, given similar drag coefficient, it is the rider's FTP that will determine a 40k result for a flat course. Perhaps a bulky rider will find it more difficult to achieve a low coefficient due to flexibility rather than frontal area issues.

Nevertheless, it would be interesting (fun) to compare 2 values:

1) 40K TT / FTP ratio
2) 40K TT / FTP / Kg ratio

Both. The 40k was done in Sept of 2005, on a personal worst (for 40k) power of 3.83W/kg. My Sea level PB for 40k is 54:20 (2001), in 2004 I rode 54:58 on the same course with right around 4.0W/kg and almost exactly the same setup as the 2005 PB (at 6500').

The 10 is from 2004, the last 10 I rode (sea level). For a recent result in the 10 mile range, I did 14.45 miles in 30:58 (28mph avg) at roughly sea level (Phoenix area) in Feb of 2006. I also did 9.2 miles in 18:36 last August at a weeknight TT, again closer to 6500'. That would extrapolate to 20:20 for a 10 miler. All those shorter TTs were done at right around 4.2 - 4.3W/kg.

The point I'm illustrating is the importance of both air density and attention to details in aero positioning for time trials, as acoggan alluded to.

Also, I'm less affected by altitudes up to 8000' than most. My power drop from sea level to that elevation (I live at 7000') is less than 5%. Most people, even acclimated, see 10% or more drop (it's very individual).

I have a slightly faster (5 year old) bike and bars for 2006, and I've tweaked my position a bit more...So I'm hoping to go a bit better on the same power (at age 39 and my 20th season of racing, I'm not expecting a big power increase anytime soon). I've gotten 3 silver medals in state TTs in the last 2 years, so I have to change something if I'm going to win!

 

[scotmart]

JBV is obviously a highly experienced timetrialist. Along those lines, my feeling is that, given similar drag coefficient, it is the rider's FTP that will determine a 40k result for a flat course. Perhaps a bulky rider will find it more difficult to achieve a low coefficient due to flexibility rather than frontal area issues.

Nevertheless, it would be interesting (fun) to compare 2 values:

1) 40K TT / FTP ratio
2) 40K TT / FTP / Kg ratio

Comparing people's times on different courses is pretty worthless. Even if they are dead flat, there can be huge differences, and not just due to the obvious air density (altitude/weather/temp) differences, but also wind, and 'course particulars'.

A while back there was this discussion about 25 times, and this guy from the UK couldn't understand why everyone's times were so slow. He gave several examples of people doing 50-51 minute 25's on flat courses with 300 or so watts. In the end it finally came out that like many TT's in the UK, the one he was giving times for was run adjacent to a motorway with heacy truck traffic. That alone can be worth 2-3mph (or 3-5 minutes over a 25 miler...).

But even that aside, there is likely to be huge differences in CdA for a given body weight. Due not only to people's different tolerance for getting aero, but also how much effort they have put into getting aero.

Even on the same course it's a bit sketchy. Ask Lance what he thinks about comparing times on the same course (if you correct for the wind difference, he beat Zabriski by a good margin last July).

I'd stick with what JV was getting at. Don't worry about what other people are doing, you know how much power you can make, work on getting the most out of it =).

Scott

 

[esandman]

As a big guy who's not really a sprinter the advantage on flat time trials is all I have. Although it's not the only factor (as suggested) I'd like to think there is some advantage to being able to produce ample power when I don't have to battle constant acceleration or gravity and when no one can draft off me.

Erik