Yet another FTP question (sorry) Using a 10mTT for FTP setting

OK, I have listened carefully to the TR podcasts and advice on FTP testing, ramp tests and how it is a guide to the training level.

  • 3 months ago I did a Road bike ramp test of FTP test scored 238.
  • I have used 238W for my TT bike on turbo since January. I am reasonably comfortable doing threshold sessions at 238W (Just).
  • If I try to do a ramp test on the TT bike I crash out with an FTP of 220W. So I ignore that and carry on at 238. (The ramp test simply does not seem to work for me. I suspect I am missing some top end power.)

Saturday I did a 10mile TT. Clocked 23.07mins on a flattish dual carriageway. (E2/10) Max Average power over 20mins 249W. Normalised power 253W.

So that suggested to me that my FTP of 238 is a bit low. However if I assume that the 20 minutes is the result of a 20min FTP test. Then I have to apply the -5% adjustment to the Normalised power that gets me back to 240W. If I apply it to the average power I get to 236W.

My temptation is to up the FTP slightly to 240W for the next few weeks. I am in the 40k TT power build, but also doing longer 50-60mile TT rides as I am aiming for 50-100m TTs as well, as 10s and 25s, this year.

So, does 240 sound reasonable, or should I use the higher average or normalise powers?

Considered thoughts appreciated…

I’d expect a 2w difference in FTP could be possible depending on how good you’re feeling on the day.

But, given the variation in pedalling and therefore power, I also don’t think that a 2w difference in ftp will translate to much difference in your training. Having said that, it’s also small enough that you can give it a go and not completely blow up if it’s too high

1 Like

Here are my thoughts:

There are differences in power output in the upright road position and the aero TT position. This could quite easily be the difference between your first and second FTP tests (238 vs 220 is less than 8%).

There are also differences between indoor and outdoor performances due to cooling and pedalling dynamics.

These two factors could make your indoor FTP in the upright position very close to your outdoor FTP in the aero position.

Holding power above FTP for 20 minutes shouldn’t really be taken as a sign that your FTP is too low. FTP is power that you can hold for anywhere between 30 and 70 minutes, depending on your physiology and how well trained you are.

If the 20 minute average is not preceded with a 5 minute all out effort the result is not valid for applying the 0.95 correction factor. Even if there was a max 5 minute effort the 0.95 x 249 gives an FTP of (as you stated yourself) 236, so how you think it’s too low at 238 is beyond me.

Having said all of that, you’re talking about differences of 2 Watts - it really won’t make a difference to your training but don’t get sucked into thinking that you need to try to justify the highest FTP you can.

If you’re on the trainer in the TT position, you may be better off using 220. If you really want to know if the ramp test result if a fair reflection of your abilities, do The FTP challenge.



2w difference will make no odds either way - sounds like ftp pretty spot on. Don’t over think it!


Thanks Mike, To your last question, I have been on the trainer in a TT position and holding it pretty constantly, using 238W FTP. I swapped to my TT on 1st Jan and have been training ion that and in a TT positon since then (at 238W).

For the 10m TT I did a 6 mile warmup including some efforts at FTP, eased off, and went to start with 7 mins to go to get head straight…

Yes I saw the FTP challenge. I have an 18.7TT followed by a 25mTT the next two Saturdays but I may try Dardanelles and see how that goes.

I guess this is the discussion between:

  1. FTP from the ramp test as a way to set standard/level for TR sessions
  2. What is actually happening on the road.
    and how (1) translates into (2).

I shall stop overthinking this :slight_smile:

1 Like

Mike, does the “FTP Challenge” assume an average FTP or Normalised? I realise on a turbo they should be pretty similar, but I suspect they might vary at least a bit.

All FTP calculations from various tests use average power across whatever timeframe you’re considering, not normalized power.

I had similar dilemmas last season racing TTs in the UK. FTP is slightly more complicated than a single test, although this usually gives you a ballpark figure. If you are looking at only doing 10m TTs I find doing the 20min FTP a good way to set your training zones, based on the x.95 figure.

If you are planning on riding longer events 40k (25m in UK) then I’d look at your power for the first one of the season, decide if it was a consistent steady state effort and your average power for that would be a really strong representation of your actual FTP, it will most likely be a bit lower than the 20min or Ramp Test figure.

Last summer, I found trying to do VO2 max workouts at 120% of my 20min test figure too hard, however when I set FTP based on my 25m TT figure I got through them (just). Also worth bearing in mind that FTP varies from day to day, it isn’t a constant for weeks at a time, so if your doing say 2 x 20mins threshold and it feels easy, I’d increase the intensity a couple of per cent to get a better workout, on the flip side of that, if you’re struggling on a given day, reduce the intensity so you get the work done, unless you are absolutely not going to get through the workout in which case extra rest is probably best. I’ve found that being flexible with regards to your FTP and also using RPE (rate of perceived exertion) rather than fixating on a single number has helped me train much better.

I only train outdoors on my TT bike, as I find it too uncomfortable on a trainer, so for say 2 x 20 workouts, I’ll ride to my local club 10 midweek, race the TT, hand my number in and then do a 20 min effort on the way home, then recovery for the rest of the way. This also helps with bike handling skills, which you don’t get on the turbo, there’s more to riding TT bikes than just power. Good luck for this season.

Thanks @Greased_Flea, that really helps.

  • Yes I find Vo2 max workouts harder and am deliberately adding some in to top up my top end.
  • And yes I am doing, (as we may have discussed previously) TTs from 10 to 100m.
  • Completely agree with being outside and bike handling. Did a 45m sessions today. Did an extra 11m after the Saturday race (after some rest). You can adjust the TT bars inside and then find they are horrible outside. and there is getting used to crosswinds/gusts/deeper wheels etc etc.
  • Oddly I am quite comfortable on the TT bike on the turbo. What I have just done is completely strip the TT bars and clean them because I could see the salt incrustation. Not good.
  • However I do like the structure of an indoor session. What I do miss is the road bike hilly rides. I can only fit so much in.
  • I like the idea of small adjustments - it did feel like cheating a bit, but thinking more, as you say, it is sensible.
    First 25 is weekend after next so will see about that and how it goes. Thanks again.