FTP down considerably with new bike

I bought my first bike (a traditional road bike) almost a year ago and a Wahoo Kickr Core a few months later. I used Zwift to do most of my training. Three months ago I finished my first 70.3. At that time I had an FTP of 300 on my road bike. I took about 3 weeks off from training after the race. I did some light training for the next 6 weeks; nothing serious. Just putting pressure on the pedals, however, I was still using my road bike on the trainer during that time.

I did an FTP test 3 weeks ago and my FTP was down to 230. Would it be normal for it to decrease by that much? I did a spindown calibration before the FTP test on my Wahoo.

I will also add that during that easy 6 weeks of training I bought my first TT bike. I used it for that FTP test I did 3 weeks ago. I’m sure it does make a difference switching from a road bike to a TT bike in your FTP but I certainly wouldn’t think it would be that much of a difference, right?

Lastly, I am doing the 12 week FTP builder program and it is using my latest FTP of 230 to structure the workouts. I am now on week 4 (using the TT bike) and it is really easy…like my HR isn’t hardly getting above 140 on the “hard” workouts. Should I set my FTP higher? Keep it the same? Redoing the FTP test would probably be ideal but I want to avoid that if at all possible until I’m done with the 12 week program.


That’s quite a significant drop in FTP but given that you’re using a calibrated trainer you might have to accept it.
Doing an FTP test on a TT bike could explain it. For me my power drops in the aero position.

Given you had 6 weeks off that’ll have an effect. Your cycling fitness starts falling after 3/4 days.

You may have also been on fine form during your initial test and then not on the money for the latest one.

If the workouts are too easy you can increase the intensity during the workout.

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I would guess that you are having trainer accuracy issues.

You didn’t state how long you have been a cyclist.
A ftp of 300 is really pretty good, so good, that it usually takes some training to reach.
Very doable but usually not accidentally.
Doesn’t matter what you weigh or w/kg.
300 watts is a lot of work.
The bike on the trainer can make a difference based on posture etc but this difference see very large.
I have seem power changes do to temp fluctuations so I recommend calibrating for every use.
I don’t use a Wahoo kicker core so can’t offer suggestions specific for that.

I would re do the ftp test, it sounds like your recent test just didn’t work correctly if the workouts are feeling to easy.

If you just continue you won’t get the full benefit of the programme and you won’t have a good comparator for your post programme test.