So this is something that has been perplexing me now for a while without much noticeable impact but it appears to be worsening over time and with the nicer weather meaning more outside workouts, it is impacting my training, which isn’t ideal.
I’ve been running a left-crank Stages G2 (bought used) for 18 months or so now and it’s been fine, no doubt better than the wheel on cheapy turbo I had initially. However, it seems like something isn’t quite right with it any more, it’s either started under-reporting power over time, or I’ve been slowly de-training over the last while (despite being measurably faster etc). My FTP by the Elite Direto PM is ~315 whilst the Stages FTP is 273 by my last ramp, 12 W down on my post-Winter FTP, also on the Stages.
I’d have thought the offset here would be the other way around, with drivetrain losses etc. Regardless, that’s still a big offset, even with doubling of left leg etc etc.
It gets more perplexing looking at the five main intervals, where the Stages reported power tails off as the interval continues. This ends up about 40 to 50 W difference, the same happens in both ERG and slope mode.
This means when I head outside I end up cooking myself depending on the session, and not able to workouts later in the week. Ideally I’d be using Power Match, but I feel like the Elite swings wildly trying to keep up and it’s unusable.
It doesn’t stabilise over time, there appears to be no effect of temperature, cadence or zero-offset changing. I’ve removed and inspected the crank and no damage is visible!
Is it time for a new power meter? I’ve contacted Stages, and will see what they say but I’m keen to see if anyone else has seen this sort of drift before?