Wahoo kickr18 Design flaws?

See the problem of shaft corrosion on the network,Kickr18 vibration and noise, is it just a matter of time?Look at the frequency you use, maybe 1-2 months, maybe half a year?

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This is a picture I took the other week. I’ve had problems with vibration lately. The trainer is about 6 months old. I solved the vibration issue buy putting loctite on the axle, new SKF-bearings is in their way. Seems like a good idea to also put some grease on the shaft.

As an engineer I’m surprised that Wahoo could screw-up such a simple construction.

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Thank you for your method

Glad if I could help!

I might as well expand on my thoughts regarding how I (temporarily?) solved my issues.

First a word on why it is made the way it is; Since the Poly-V pullies must line up with each other any axial play must be taken care of in the other end of the shaft, hence the wavy washer on the flyweel side. For that solution to work the left bearing must be able to float on the axle. With better manufacturing tolerances the axial play should be possible to be minimize so the washer could be omitted.
Over time this play seem to have increased with vibration resulting in vibrations. I guess the bearings also has loosened adding to the problem. My solution interfere with the original construction since the left bearing can no longer float. This is not a problem since the width of the base is fixed and is probably only a way to take care of variance in the manufacturing process.

The corrosion problem should be easy to solve putting some light oil or grease on the shaft. I’m surprised it has started so soon but if corrosion wasn’t one of the original construction parameters it could happen really fast in a sweaty “pain-cave”.

I just want to make sure anyone who tries this understands what they are doing since attempting what I’ve done potentially voids any warranty.

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Does the heavy flywheel create a combined load (radial + axial) on its supporting bearing? If so, does it make sense to replace the deep ball grove bearing with an angular contact bearing?


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The shaft in my Core looked pretty much like that (photo in first post) when I pulled it all apart. It started to sound a lot like a didgeridoo a few days in to NZ lock down (a total lock down - no chance of getting it looked at or replaced for what turned out to be 7 weeks, by which time there would be no chance of a replacement for months so I just kept riding it). It was almost a year old, and probably just out of warranty by the time we came out of lock down.

For some reason I couldn’t get the bearings out at all, they seemed stuck fast. They were a bit grumbly to turn but really didn’t seem that bad. All I could do was spray them with CRC and put a bit of grease on the outer of the bearings. I greased the shaft as well and made sure the woodruff key was correctly in place just in case that was any part of the problem. And then for some reason the shaft would NOT go back in. I had to file it down. Probably part of the problem in the first place. It sounded exactly the same.

I’ve just replaced it with a gen 5 so I’m back to having a quiet trainer, and will pull the Core apart again at some stage and see if I can do any better without the fear of being without a trainer. Unfortunately I’ve already seen reports of issues with the gen 5.

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I’d say no, there are no significant axial forces to consider. The fact that the flywheel is positioned offset doesn’t impose any axial forces, if that was the hypothesis. I have replaced my bearing with high quality SKF bearings of the same type and put some Loctite where they are seated to keep them in place as the tolerance allowed the flywheel side bearing to fall out if the trainer where to be tilted sideways, which is to loose imo and could add to the radial play in the system increasing load on the bearing.

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Thanks for the input, Tomas!

Since I decided to fix my Kickr by myself here in Brazil, I spent some time learning about bearings, loads, shafts, fits etc. I’m not an engineer, but your thoughts about the causes of vibration are the most plausible from all the research I did.

I already bought SKF bearings to replace the original ones, but I’ll do something else in order to try to achieve a permanent fix: a new shaft made with high quality material and better tolerances.

I’m not sure if I’ll keep the original design (clearance/slip fit) with the flywheel side bearing, go to an interference fit like you did with loctite or, maybe, somewhere between the two (transition fit). The shaft is being fabricated by a shop specialized in precision motorsports parts, but any thoughts are very welcome!

As this project goes on, I’ll get back with my progress.


Hello portoga.
I’m thinking about doing the same fix. But I have a question. How do you disassemble thé shaft from thé flying wheel. Did you make à 3d of the shaft that I could use for manufacturing ?

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Hello Thasa128,

First of all, due to absolute lack of time, I haven´t posted the outcome of my DIY fix on TR’s forum, which, fortunately, is working perfectly. When I find some time I’ll post details for other TR forum members.

Second, if you have more questions, we can continue this conversation through email. It will be a pleasure to help you out.

Now, answering your questions…

“How do you disassemble thé shaft from thé flying wheel?”
Re: The shaft is pressed into the flywheel. It was taken out by the shop that fabricated the new shaft and, according to them, was no big deal. I took the whole assembly (flywheel + shaft) to the shop and received the same assembly with a new shaft.

“Did you make à 3d of the shaft that I could use for manufacturing ?”

Re: No. The shop that fabricated the shaft took it apart and replicated it’s dimensions with extreme precision.


  • About the shop that fabricated the new shaft: they are specialized in high precision motorsports parts, so they are used to fabricate parts for high demand conditions, like Brazil’s Stock Car Series, Porsche GT3 Cup etc.

  • About the bad shaft (please see attached picture): according to the owner of the shop, the original shaft was made with a low quality steel alloy and the tolerances were all screwed up. The new shaft was fabricated with a much harder alloy (stainless steel) and now the bearings are pressed into the shaft (interference fit) to ISO standards.

  • About the outcome of the DIY fix: it’s been working perfectly so far! Due to lack of time, I have put out only around 10h of use with no issues so far.

  • Would I do anything differently? Yes, but only in a very small detail. Now the bearings are pressed to the shaft, and, because of this, the shaft no longer floats sideways. This setup caused a small misalignment between the belt’s pulley (please see drawing).

As the belt is a v-belt type, it jumped to the next available groove. It’s easy to solve this issue by removing some material from the pulley that’s connected to the shaft, but as everything is working perfectly, I’ll postpone that fix when the belt needs to be replaced.


Ronaldo Spinola


Thank you very much for your answer and the speed of it.
I’m glad that you’ve managed to repair your kickr.

I also might have the way to produce a new shaft at my workplace.
I’m sure the original is made out of poor steel. You can see the damage done by the bearings on mine.

For the price of the kickr I expected far more good quality.

Thanks again for your help.


Maxime, I totally agree with you regarding the quality expected from such an expensive equipment.

Let me know about the progress on your fix.


Ronaldo Spinola

Is there a bushing on the shaft between the bearings in the Kickr18?

Hey Portoga,

Thanks for posting the photos and solution you used to get your Kickr repaired. The shaft on my Kickr is experiencing the same issues everyone else is. Mine is worn away on the drive side and the flywheel side has minimal wear.

I’m thinking of doing what you did and have a new shaft made up, but keeping the floating system in play. I’m going to add a new flange head bolt with washer and new wider key to stop the sheave/pulley from moving on the shaft. Just like Wahoo did to resolve the problem early on for people who didn’t have as much damage to the flywheel shaft.

Curious to know how your fix is working out and if you considered what I’m thinking of doing?


my Kickr is working flawless since I did the fix. I’ve put a lot of hours of training with absolutely no issues.

Regarding the fix you’re thinking of doing, I think it will solve your problem. I’m not an engineer, but it seems that the root of the problem has two main reasons: first, the alloy used on the shaft seems to be too soft; second, the diameter of the shaft is way to small compared to the bearing inner race bore.

If you have a new shaft made up with high quality alloy making sure the clearance between the mating parts (fit) is within tolerance tables, I think you’ll be good to go.

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I’m an engineer and I agree.

Hi Ronaldo, I have the same problem as you did and live in Petropolis, RJ. I have not been able yet to remove the pulley from the axle because it seems to be stuck. I am going to buy a pulley extractor to pull it loose, but wanted to see if you could pass me the contact of the shop that did your new axle and fixed it in the flywheel.


Just wanted to let you know I was able to get a new shaft made. I put everything together and the Kickr is working well. I’ve been using it for several months and no issues, but! I plan on taking it apart after the indoor season and see if the new shaft can take the wear and tear put on it by the Kickr.

I wanted to thank u for posting your earlier comments. It helped make my decision to tackle the job of repairing the Kickr on my own.

Glad to hear that it worked for you! :smiley:

Hi i found this solution online.

What do you guys think?
Where should i have the new axle pressed in?