I'm getting a new rear tire today and then going on a ride this Sunday with some friends, does anyone know about how many miles needs to be put on it before properly breaking them in?
-Cody

 

id take it easy for about the first 100 miles or so.

or go do some burnouts

 

It varies from machine-to-machine, rider-to-rider, and tire-to-tire.
I would try to ride it around a hundred miles, start out tippy-toeing around corners, and gradually build up.
I [re]learned the need to take it easy on new tires back in September of 2006:


Was too busy thinking about the upcoming weekend, preparing my gear to climb Mount Whitney, getting the bike back to my friend, calling this girl I knew back then before embarking on my climb... ended up losing all those things AND the bike (AND three broken ribs and about a square foot of skin off my left leg) because I didn't give it the attention it deserved.
Peace and safe riding!
-CCinC

 

P.S. Metzelers last a long time, but they also take a longer time to scrub-in, IMO.