H3 Newbie Advice

Hi, just upgraded to a Saris H3 from a Tacx Flux and got a few queries.

For info if it matters it is set up in my dining room and normally have window open and 3 fans on the go.

Spindown - was always 1-2secs on Flux, 12secs on H3, is this normal? Takes forever for flywheel to stop.

Calibration - Flux daily before ride, H3 says doesn’t need doing everyday. What are people’s experiences and do you warm it up for 10mins before calibrating?

Ramp test - if calibrate after 10mins, is it ok to pause the ramp test 10mins in or will this affect the test?

Power readings - did a work out ranging between 50-75% and found power differences between H3 and Garmin Vector 3s pedals. Some intervals matched yet others varied up to 3-4% with pedals reading higher.
I expected some difference just seems odd that it’s not consistent.

Any thoughts/advice appreciated

  • Yes, that is what you paid for. The H3 has the largest and most effective flywheel in the biz.
  • Always do it warm. I do it at the end of a workout. If the trainer stays in the same environment, its calibration is only needed about every two weeks.
  • See above, calibrate in a workout a day or more before the Ramp.
  • Do not calibrate during the Ramp.
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If you’re moving the trainer, then calibrate after each move. Otherwise, a routine, like weekly is best. Also big temperature changes from the last run, I calibrate.

It also depends how you are comparing it. If you’re just watching the power changes on screen, then it’ll never really look right. Or compare average power over an interval. The best is to make 2 recordings and compare them with a tool to really see.

Thanks @mcneese.chad, I thought it would be because of the bigger flywheel but just wanted to check.

I’ve noticed that the power discrepancies are greater at lower power (recovery valleys) and are as much as 10–15% over the full interval.
Would you use powermatch and work that bit harder or stick with H3 power readings?

Thanks @iamholland, it’s compared at the end of the workout as an average

If you always have the bike with the power meter on the trainer, Power Match seems like a good idea. It like using the same exact tape measure for everything vs 2 that are close, but potentially different at some lengths.

I know Power Match experience can vary. Some love it, some hate it. Comes down to specific equipment, rider input and expectations. Worth a test at the very least and decide from that.

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Spin down -12sec seems short. Should be closer to infinity with that unit.
Calibration - With my H1, just needed it close to never. I did it every time I changed the bike out though.


Agree with Chad. PowerMatch for consistency. It’s hard to tell which power reading is closer. Also power readings change, big ring vs small ring. Flywheel speed has an impact. The h3 is more susceptible to faulty readings at higher flywheel speeds.

The only way to triangulate the power is with a third power meter. Barring that, PowerMatch, so if you change trainers you have some way of keeping your numbers consistent.


First time was a lot higher so did it again to check :joy: