Any users of power meters have both a pm on their road bike and their mtb?

Do you notice any difference in the power curves? Is there a consistent variance?

I’m noticing fairly huge differences in the max power to 10sec segment. Wondering if it might be the pm itself, limited dataset so far so not conclusive.

Shouldn’t be any difference, although it may be that on the MTB you come up against far more super short sprinty bits than you do on the road, so it’s a fairer reflection of your ‘real’ 10 second power.

GUESS incoming:

might a pm freak out briefly if you put a big impact through the pedal/crank, say landing a superschweet jump or a drop, or even just hitting a squarish edge ?

(presumably not if it’s a hub-based one)

Maybe something like that, on the road my max power is somewhere around the 1100w mark which I see regularly hit roughly 900 every commute up a sharp 8%er. I have seen up to 1800w on the road but always assumed that was a erroneous spike as very rare. First proper test of the mtb power meter and saw several spikes just over the 2000w mark which surprised me. Overall averages for a 2hr ride were consistent with road, so it is the sub 10sec stuff which is different. Could be more effort with short surges than you really do on a roadie.

Both stages units, so only left crank measured.

https://www.britishcycling.org.uk/about/article/20170227-TrainingPeaks-University-conference-coming-back-to-Manchester-0

Are you ” leveraging advance learning metrics”?

They’re big numbers, unless you’re either >120kg or a world class sprinter I doubt you’re getting >1500w.

I’ve got a Powertap on the road and a Quarq on the mountain bike. Most of my power records between 1 second and 8 minutes I’ve set on the mountain bike, mostly because I tend to do higher intensity rides off road.
Can’t say I’ve never seen massive spikes like the OP or others have described, max power – I top out at 1400W whatever bike I’m on.
I had one worrying moment where the Quarq stopped working after I hammered it into a rock, but a new battery fixed that, must have rattled the battery loose or something.

Depending on the time of the year I’m between 72 and 82kg with a current ftp of 268, summer usually hoovering around 300. I have stages on 2 road bikes and a kickr for 18 months or so so confident I have a ‘honest’ power curve across the three. It’s this new one on the mtb seems to be chucking up huge numbers. I’ll give it a couple more outings then maybe it goes back…

” leveraging advance learning metrics”?

What the hell does leveraging mean? Why do people use these silly made up words?

To answer the question, my guess would be that it’s to do with impacts through the cranks. Of the people that do use power meters on the mountain bike, they say that they can get funny results due to this

All same generation stages? I wonder if the mtb has had a firmware update that means it’s processing something differently?

I wonder if pedal kickback is affecting your power spikes DT78?

I used to have a 20 minute power output of 330W, and I consider myself sprint biased but even then I could only get to 1300W max for a few seconds and that was with far more effort than I’d put in on an actual ride for fear of breaking something. Like the freehub I ovalised through sheer force 🙂