The shaft tapers as it gets near the tunnel mount, and the bearings were junk I had around. The snap rings are crap, the old phazers had em and they sucked there also. Came back from a trip in March with the snap ring slid all the way out, the wheel destroyed. Luckily it must have happened right at the end because there wasnt any track damage. There are two set screws. I was goint to just put the bearings with the set screws in the wheel, but the plastic of the wheel would interfere with tightening the screws, so I ground down some old bearings. 20 minute job.I'd like to understand what the advantage is? It seems like you're going down to a single point of contact of a set-screw vs. the 340-350 degrees of contact of a snap-ring against the inner race? It may be slight but I would expect the set-screw to booger the shaft making another obstacle to slide the bearing off the shaft. I wonder if going to the work of a set-screw set-up why not make sleeves that extend all the way to the end of the shaft against the tunnel mount on each side? Thanks