When I installed the 18" rear wheel, I wanted to maintain as close to stock rolling diameter as possible - a 140/70x18 rear tire is only 1/2" larger in diameter than the stock 130/80x17. Unfortunately, tire choices in that size are limited (no Metzlers), so I chose Bridgestone Battlax BT 045. I only had 2,000 miles on the front tire, but I swapped out the stock front Metzler too so I'd have a matched pair. Much to my surprise, the 'Stones are a much "quicker" handling tire, providing **a lot** more grip and much quicker turn in. I wondered if the extra 1/4" in ride height at the rear reduced the rake enough to change the handling, but I then figured 1/4" is about the difference between a new and worn out tire. The BT045s are a dated tire design, but they certainly made a big improvement over the stock Metzler rubber.