New trainer - huge FTP boost....normal?

Hi all, last week I installed a Kickr core to replace a wheel on Tacx bushido. Trainings felt supereasy this week so decided to do Half Monty today - previous results were about 6 months old. Feelings confirmed - huge increases in FTP and MAP, both 15% higher. Is that normal? Or should I spin down the Core once more and bring myself back to earth?

Not exactly the same as you but when I changed from virtual power to pedal-based power meter my wattages went up by about 50-60%

I could well believe there is a discrepancy between different types of trainer. The only thing to do really is to retest with the new kit.

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You can definitely get different power measurements from different devices. I’m not an expert but 15% change doesn’t seem out of the realm of possibility to me. However, maybe some of that is your improvement and some is the device (you mentioned it suddenly seemed easier). I have a roller-based trainer now (not direct drive). The algorithm in those trainers does not “know” the rotational inertia in the bike wheel and powertrain - it is guessing on that parameter when calibrating. I would tend to think of the direct drive as a bit more accurate, and pedal or crank measurement as better yet. As long as you set new targets based on your new measurement (seems required for a new trainer or power device) then you are all set in any case.


If this was a sudden change after swapping trainer then I would think the gain is almost certainly down to the trainer. The good news is that your Kickr is likely to be more accurate than your old wheel-on trainer. So your new higher numbers are probably genuine. I would do another spin down and call it good if things don’t change.