I have a 21" RC Components with Metzeler's on my front and a 17" on the rear. Didn't drill out the front fender mount and have had no problem. I had read that the Metzeler fit better under the stock fender, apparently the Avons are taller in the middle of the tread and can cause rubbing.

 

I am installing my new 21" on my Street Glide hopefully next weekend when my wheel comes in. I understand I need to drill out the back fendor hole about 5/16th of an inch to prevent rubbing. What is the best way to accomplish this and is it as easy as it sounds? Anyone have any pics or link to video that shows this? Thanks

 

21" PM Heathen with a KlockWerks Slicer fender. No issues at all. Bolted right up. It also fit under the stock SG fender that came with the bike.