Originally Posted by JimmyMac

For club racing in 17.5 I start mine off at 42mm rear and 41.5mm front. They can be a little edgy at first but they break in nicely. Just be sure you superglue the front side walls. Some of us sand down the superglue to make a nice smooth edge. Here's what mine looks like. I've seen them even smoother than that. Just depends how much time you want to put into them. Cut them down, then superglue the front outside. Let dry, then toss them back onto the lathe and sand the superglue down with 600 or 800 grit sandpaper for a smooth finish. I can get 2 race weekends out of a set. Maybe 3.