KICKR Core Spindown

New-guy here with a calibration question. I just completed new spindown on my KICKR Core today using the TR spindown calibration after 10-minutes riding. I then completed my second Ramp Test in the last 6-weeks (SSBLV1 just complete). The spindown seemed like it said it was done before the wheel stopped spinning. I still let the wheel spindown completely.

Everything felt as I expected it to. My FTP went up around 9%. I started from a very detrained state. I was just curious what you should expect to see for a spindown. Since I’ve only been doing them once a week or so and I spend some time on a Neo I do not remember what is a normal value for the calibration.


I can’t comment on normal values but I do a spindown 3-4 times a week and it always completes before the flywheel is done spinning so I’m assuming that’s perfectly normal.


Spindown on most belt driven trainers with flywheels allows the trainer to be calibrated. Basically the maker of the trainer knows how much inertia is in the flywheel at a certain speed, and when it does a spindown it is testing how much resistance is in the trainer created by belts, gears, whatever. Technically it should not matter if your trainer takes 12 seconds and someone elses takes 15. This is figured into the final calibration. What would matter is if your spindown time changes significantly from day to day.

The number (offset) itself is probably not relevant to compare between different trainers, more the consistency of it.

However, for interest sake, I calibrate mine every time I train (because I move my trainer out of a separate room into the lounge for each session), and my offset is always 32768 - coincidentally the same as yours :slight_smile:

Thanks! I sort of assumed all was well but thought I’d ask the question. Out of curiosity, is the easiest way to incorporate the spin down to just start the workout with an extended warmup and then go to Paired Devices, select the trainer, complete the spin down and then return to the workout?

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So… I’m terrible at completing a calibration. I get up to the trainer, I get warmed up, and I’m normally too amped up to want to stop and wait for a calibration.

My trainer hasn’t moved in 2 years. And the temp environment is the exact same every time. It always feels the same even though I only calibrate about once a week.

Is this ok? Should it really get that far out of calibration every time?

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I believe Wahoo suggests every 1 to 2 weeks or after you move the trainer. However every ride for the most accurate results.

Another solution is to just calibrate in the recovery zone after the initial TR warmup.

  • As above, do it at least twice a month, even if you don’t move it.

Always surprises me that people skip this step and hope the data is good. We have a proven process that handles it, adds maybe 2-5 mins to any workout and only needs to be done 2x per month at minimum (wheel-off trainer in the same location).

IMHO, if you care about your training and the data around it, calibrate according to the manufacturer’s recommendations.


Thanks Chad. I’ve seen you post on this in several places. I actually do not mind the calibration step each workout. I tend to do it every couple workouts or after my trainer has sat for a couple of weeks idle while I’m travelling. Thanks for your input (and thanks to whoever organizes this forum…it’s one of the best user-interfaces I’ve ever experienced in a forum.)

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TR picked Discourse as the forum platform, which is the best I’ve used in many years of forum access (awesome features).

I just help with setting Categories and Tags, searching for related topics, and the rare instance of keeping us pointed in the right direction. Honestly, this is the best forum experience I’ve had and it’s due to all the great members more than anything. The level of respect and willingness to help here exceeds any other I’ve seen.


As a new-guy to structured training I could not agree more.

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Thanks for the reply. I do calibrate about once a week, it’s just never at the forefront of my mind. I get on the bike and start turning the pedals and get in the zone and don’t want to break up my workout. The resistance and power levels seem very consistent to me working out about 5 times a week and so I guess it doesn’t make my priority list. I should probably prioritize it a bit more.

If I calibrate after the workout, does it have the same benefit? If I’m doing it once a twice a week would it matter if it was immediately before one of the workouts or after the previous one?

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You are doing it well. Didn’t mean to imply otherwise to your or the OP.

I was largely responding in general, about the fact that we see the “how much does calibration really matter?” questions with regularity here. Just funny that we spend this money on these trainers and power meters, and some choose to ignore proper practices that help make them actually work as advertised :stuck_out_tongue:


Definitely no offense taken. And I appreciate your logic because you’re right. Between my bikes, my trainers, all the accoutrements, the power meters… I’ve spent a lot and focus a lot on this regime. So it’s good to keep in mind that it’s not worth a lot if I don’t follow best practices.

I would never start an outdoor ride without calibrating my power meter. Probably a good idea to do the same on my Kickr Core.

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Anyone hazard a guess at why the target speed to hit during calibration differs from ANT (37.6kph) to BT (38.6kph)?

Sloppy coding? Likely a mistake as there is probably no reason the speed needs to be different from a comms standpoint. As long as they apply whatever math magic on tracking the time to spin down from a know value to another known value, we should get accurate calibration. That difference is interesting to learn though.

Also interesting how the numbers count down once you stop pedaling. Can’t remember which way around it is but one hits random numbers as the speed decreases to 16 kph but the other indicates every 5kph, IIRC

I try and do a spindown on my Core before my main interval sets on every workout. There’s normally at least a 6-10 min warm up before you hit your main intervals in almost every workout. Only takes less than a minute and shouldn’t really affect you.

Thanks @nickcs I’ve extended the warm-up and definitely have time then. On the ramp I decided to play it safe and just ride in Zwift for 10 mins then start TR and unpair the control from Zwift.

I calibrate before most rides. While it spins down I use the time to pair my headphones with my phone and select something to listen to. The wheel is still spinning when it says complete.