Just for public knowledge since I wasn’t able to find much searching the web other than that this failure happens a lot:

My bearings failed on my Wahoo KICKER SNAP after about 10 months of use. Turns out wahoo uses metal shielded bearings, and mine became contaminated with tire particles. Rather than send the unit back to Wahoo and have the same issue again in the future, I decided to replace them myself. I used Timken 6003-2RS-C3 sealed bearings purchased from Amazon. The job involved 2 through 5 mm Allen bits, a 19 mm socket, heat gun to melt the adhesive on the roller set screws, snap ring pliers, a shop press paired with a 11/16” deep well impact socket, extension bolt and a variety of nuts and washers for jigging. You could probably get it done with just a mallet driver instead of a press, as long as you don’t miss and wack something delicate.

Turned out better than new in less time than I would have spent dealing with Wahoo and shipping. It also kept downtime to just an afternoon.

The new bearings are Timken and “electric motor grade,” so I don’t expect to have to do it again.