my stock ones were lasting bugger all amount of time with my current set up (i was re grooving the shoes & replacing the spring almost daily), the new shoes so far have very little wear and have had no maintenance since i installed them several months ago. i like them a lot. the easiest way to get them to fit is to put the shoes on the flywheel & mount the fly wheel on a drill press or lathe & use some sand paper on a block or a file & turn them down. takes about 2 minutes if you do it with care. you also need to cut a few mm off the spring length, a dremel is handy for this.