I have a kickr I bought in November('21) so it is the latest version and I experience the same very light vibration that starts at gear 5 and gets a little worse as it goes into the smallest ring. Same happens on my wife’s bike. It isn’t the worse for me but I was wondering if it was a quality issue. Based on this thread it seems to be expected.
It makes somewhat sense, the further away you are from the bearings, the greater leverage force on the bearings. The belt pulley width reduces the distance between bearings which reduces the support. I have never been on other similar trainers, I wonder if the same thing happens since they still need to stay within the same chain stay width. Not that it matters since I am not trading in my Kickr, just curious.
I also have vibration issues with my Kickr Core, since the very beginning. In the beginning I thought it is normal so I kept using it as it is. I recently tried to contact Wahoo to see if it is a known issue and if they maybe can support me with the problem but nothing really could be done. In their oppinion it has to do with poor meshing between drivetrain components and said it should eventually go away. I have replaced the chain and cassette in the meantime but the vibrations are identical. For me it happens always when the cadence is below 80 RPM and when the power is 200W+. It is more pronounced on the big chainring. It was kind of like grinding feeling and sound and I can feel it in my handlebars.
My workaround is to shift to the small chainring when I have intervals over 200W, then it feels better. It is also a constant reminder to keep my cadence up. (My natural selected cadence is around 80-85, which also helps). I only ever use ERG with my smart trainer, Zwift will be way too loud with my Kickr so I don’t bother.
I bought a new mat from Leeze for Christmas, which is quite thick to put below my trainer, which dampens the vibrations well and the trainer feels a bit better. (My neighbours haven’t complained and my noice cancelling headphones do a good work, so it is thankfully not a problem for anyone at the moment).
At some point I considered just selling mine and getting me a Tacx Neo, so I borrowed one from a friend and I actually experienced the same vibrations, so Wahoo support may be actually right in my case. They also wrote that this happens on the road too but we don’t feel it due to road vibrations.
Sorry to bump old thread, but having same issues albeit with a Zwift hub. Has anybody tried dampers o. The axle either side of the dropouts? I’m thinking 0.5-1mm dense rubber washers. If no response, I’ll give it a try and let you know