Just got a Saris H3 to replace a knackered Elite Fluid Chrono dumb trainer. I’ve set it all up, and the resistance just seems considerably higher than before. I checked the firmware and updated that. I’ve also used the app to calibrate it. Done that a few times and the roll down time has varied from 9 to 14 seconds but seems to most commonly be around 11sec once the trainer is warmed up.

So am I missed something or is that just to be expected? I reckon I’m down 20-30 watts on a 10 mile Zwift race and it just feels hard! And I don’t just mean the increased resistance from the hills in Zwift. It’s harder everywhere even on flats. Has the dumb trainer been over estimating power by that much? Just not sure what’s going on.

Truth hurts? Literally!

My fluid was fairly close in terms of virtual power – confirmed recently by me using a power meter with the same trainer. Maybe your virtual power measurement is a little bit off? Do an FTP test on the saris maybe?

Has the dumb trainer been over estimating power by that much?

Almost certainly. Because it’s not estimating anything, it’s just a curve for the trainer based on shaft/wheel speed.

Short answer is yes , you need to do a new ftp test with the Saris , when I invested in a proper duel sided power meter and did a trainer road session with my virtual
Power ftp I had no chance of doing the session as the old ftp was so over inflated – did a new Tes and accepted my old ftp was meaningless and started again

Ok, sounds like my suspicions were right and I haven’t just cocked up the setup. Sounds like an FTP test is in order.

Funny because I’ve been doing the 100 days to xmas challenge and had increased my ftp by about 30 watts and looks like this is going to take me back to where I started! It’s no bother though, it’s all relative and just have to re-calibrate to the new normal.

I’ve had my H3 since Easter, set it up Q/R for my commuter because it was outdoor season, it replaced my hammered “riding through almost set treacle” Direto that gave a minimum resistance of ~170W in 34/34 at ~80rpm cadence (five sprockets covered my practical power range from Feb ’22).

So I’ve not been able to compare the power numbers against the 4iiii on my road bike, but it felt a bit harder for the same effort, however getting a power reading from the turbo freehub compared to the crank should be ~3%+ harder due to drivetrain losses on a clean drivetrain.

IIRC my calibration spindown times have been anything from ~11secs to 15secs, latest one at weekend increased it from ~12.3 to ~13.2, as to whether it feels easier I have no idea… Everything is a struggle at the mo!

Some riders have experienced up to ~20% loss in their power numbers switching to a direct drive turbo which must be heartbreaking if you chase the numbers, that’s months of hard training for many just to get back to where they thought they were.

Phew I’m glad I’ve started on a saris h3. They are pretty accurate according to the online reviews/blurb 🙌🏻

All my zwifting is hard

😀 I use a Neo on occasion, and still smile when seeing people mention the Neo effect.

It’s real, and it hurts.

Just did an FTP test. 270 becomes 225! The 270 has been achieved through races where I’d say the psychological side of that pushes me on more than I could muster doing the boring test itself. So taking that into account maybe I could add another 5-10 watts on perhaps if I’m being generous. So ballpark 35-45 watts down – 15% ish.

When I had similar, it turned out that the top-hat spacer behind the freehub had disintegrated. It’s quite easy to over-tighten the axle adapter on the freehub side.

IIRC one of  the freehub bearings was also knackered.

My H3 reads quite a bit lower than my power meter too. As you say, as long as you’re measuring consistently the absolute number doesn’t matter too much. Hope the ego recovers OK from the FTP drop.

I use a Neo on occasion, and still smile when seeing people mention the Neo effect.

I do tell, I use a Neo.