I've used the Pirelli Diablo 240/40 ZR 18 tire on the rear BST CF rim on my R3 for the past 2400 miles. This tire is actually wider than the stock Metzler 240, and is far superior in grip... better compound. The only drawback is that at only 2400 miles, I've already ordered another... that soft compound comes at a price. I can already see that my present rear Diablo won't make it past 3000 miles... but remember I make over 200 ft lbs torque through 7000 RPMs. I wouldn't give up this tire because of the low mileage... it's just too great of a tire. Also at $152 per tire it's a not such a "sting" as the ridiculously priced stock Metzler.
..........................and I always thought that's what they made 'Great Stuff' expanding urethane foam for................filling in the gaps............
Yea Wilbur,I heard it costs to fu##en much. Mileage should be better because they are harder. Guys on the ****** rocket sites won't use them due to hardness. Should be fun to watch the (price hopscotch) in the next 5 yrs..