I bought this tool kit to replace bearings on my boat, accessories and trailer flatbed. When the tool fits snugly on the bearing race, it works amazing. However, I have found that some of the bearing rings I use are slightly larger or smaller than the shims included in this kit. For example, the #59 number for my #60 l68110 bearing ring was a little low, which kept me riding consistently for a damn long time in that race. I used an old race to run it and pushed 1/2 of the way into the hub. In this case, the old-fashioned way has prevailed over this tool. But for $28, if the race matches the disc exactly, this tool saves a bit of time and works great. Overall I'm happy with my purchase but was hoping it would fit all of my stock raceways or be close enough to work. By the way, many of them are close enough; I'm only talking about discs that aren't close enough to be used. On the other hand, the flat side is very suitable for seals. Although my cut piece of 2x4 worked just as well.