I agree with Keith... doubt the size would matter, also agree guarding VERY IMPORTANT... Just FYI, I've been working with Les - in the future, we're planning on his parts page to have Custom Nylon pulleys for both the front pulley & the 4 side pulleys that will have double bearings each & hopefully very affordable... I will be working on these as soon as I possibly can... I have all the stuff, just need to get home to implement...