Saris H3 vs Wahoo KickR - trainer calibration in unheated buildings?

I’m looking at upgrading from my trusty Kinetic Road Machine to a direct-drive smart trainer. That would also let me keep my Assioma Duo pedals on my “best” bike - I currently swap them around so I have proper rather than virtual power on the trainer.

I’ve had the Saris H3 on my list of options based on DC Rainmakers review which said it’s excellent for ERG mode response time and accuracy. However, in his review, DC also said:

In my testing I didn’t find this necessary every time – things seemed to be surprisingly consistent for me (I only did it once). Still, again my general recommendation here would be that anytime you move the trainer, or if there’s significant shifts in temperature in the spot you’re operating it in (such as in a cold wintery garage), to do a calibration about 10-15 minutes in, just to be sure. That’s pretty consistent with what I’d recommend for any trainer except the Tacx Neo 1/2, which require no calibration (and don’t even have the option to do so).

As my turbo lives in an unheated, detached garage I’m wondering how often I would need to calibrate an H3? Through lockdown I’ve been completing a SUF session most weekday mornings before breakfast. If I don’t mess around too much, I can squeeze in a workout of up to 55 minutes (Nine Hammers before breakfast? Certainly starts the day with a bang). If I need to spin for 10 to 15 minutes, calibrate and then start a session I’d not have time for the longer sessions. Or could I start a SUF session and calibrate after 15 minutes? I’d expect that to potentially skew figures though.

Looking at the temperature trace from Edge 800 from my ride (Get To The Other Side) this morning. The temp drops from 10 deg as the Garmin gets use to moving from the house to the garage and then levels out at 2 deg for the last hour of the session. And yes, I have considered putting overshoes on once the fan goes on as by the end of the session my toes are numb!

Another attraction of the H3 is it’s around £150 cheaper than a KickR v5 in the UK. However, the new continuous calibration in the v5 could be a winning factor…


PS. I did ask Ray Maker and but didn’t have a definitive answer, so suggested trying the TR forums. Then David McQuillen suggested asking in here - not sure why I didn’t ask earlier to be honest.

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Hi @Harpoon! I am working to get you some good information on the Kickr v5, luckily I have an “in” with some people at Wahoo :wink: I’ll get back to you as soon as possible with details!

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Thanks Rebecca - be interested to hear what somebody at Wahoo says.


This is a really interesting question! I have used a Kinetic Road Machine for years. For the last 3 it has been in my unheated garage. I live in MIchigan in the US - temps in the garage are commonly +5C/41F down to -20C/-4F.
@Harpoon, what was your experience with the Road Machine? I have the impression that the resistance is “high” until it is warmed up but that once warmed up it seemed pretty consistent despite air temp difference. However I never wanted to take the time to cal every day either. What did you think of it?

I am interested in this, as well. My temps aren’t as extreme, but I have my Kickr Core in an unheated garage here in Las Vegas. In Dec and Jan we regularly have temps around 34-40F at night. I usually ride first thing in the morning (5am) before the sun comes up. With my fan on I’ve had my toes go numb a few times this winter. During the day it usually heats up to between 55-65F.

I wonder about the temperature change inside the garage during a ride and how that affects the trainer, as well.

In the summer I put a thermometer next to my water bottle. Just me, my exercise, and the trainer alone would raise the temp around 5 degrees. At 4:30am I would often start a session with a temp around 85 and end with it around 90. A few times I would finish with the temp close to 95. Needless to say I go thru a lot of water in the summer…

Some extreme temperatures in the US!

@jackriddle2 - I’ve never really given much thought to the temperature effects on my Road Machine. I check the tyre pressure on the bike once a week or so to keep that consistent and that bike lives on the turbo now, so the roller pressure doesn’t change. Do you have a calibration routine? I didn’t think there was much else you could do with a dumb turbo like the RM?

@Harpoon, I also leave that bike on the trainer and almost never touch the roller. I have the “Road Machine Smart” (not control) which has a spindown-based calibration routine. It can certainly tell you if the calibration is plausible. You can tell if it has drifted at all based on the number provided (“Cal Factor” should be between 1.6 and 1.8). I have no indication that the unit actually corrects reported power based on this calibration so I just try to keep it consistent. Same thing you reported - keeping tire pressure set and leaving the roller alone unless I move the trainer. I also clean the roller and tire now and then. As the roller has gradually become polished smoother and smoother, getting the right pressure is a bit of an issue!

I’ve been discussing this with some of our Wahoo friends and the support team generally recommends that if the trainer is in temps below 50F then you will want to warm it up to operating temperature by riding for 10-15 minutes and then doing a spin down. This will ensure that you are getting power accurately reported.