not another FTP question? different though.

PSUcycling said:

i like being able to verify my current ftp as many different ways as possible, so that i know the number is fairly accurate.

I'm currently estimating it to be 320-325, this is from a race i did 3 weeks ago. fairly hilly, in a break and had a NP of 325 for 72mins.

THis weekend I had an NP of 310 for 3.5hrs, can you calculate backwards? i heard somthing like losing 5% everytime the duration doubles past 1hr.

Since everyone's power-duration relationship is different, that's far too crude of an approach to trust.

PSUcycling said:

THis weekend I had an NP of 310 for 3.5hrs, can you calculate backwards? i heard somthing like losing 5% everytime the duration doubles past 1hr.

Using that thumbrule you'd expect a 10% drop from 1hr to 4hrs, which would indicate a 345w 1hr NP value.

For you previous 320-325w FTP estimate, you might expect to see 1hr NPs of up to 5% greater, or 341w on the high end. Given the 3.5hr duration instead of 4, I'd say the longer race helps correlate with your previous FTP estimate method, if that's what you're asking.

frenchyge said:

Using that thumbrule you'd expect a 10% drop from 1hr to 4hrs, which would indicate a 345w 1hr NP value.

For you previous 320-325w FTP estimate, you might expect to see 1hr NPs of up to 5% greater, or 341w on the high end. Given the 3.5hr duration instead of 4, I'd say the longer race helps correlate with your previous FTP estimate method, if that's what you're asking.

yes, i was more interested in making sure that the 3.5hr NP agreed with what i had estimated already.

this weekend has a 35-40min TT which should be a good test for FTP, although i live at 20' (yes twenty) above sea level and the TT starts at 5000+ !!! maybe not!

acoggan said:

Since everyone's power-duration relationship is different, that's far too crude of an approach to trust.

thanks Andy, always appreciate your input.

j