About 9k miles ago I put new front and back Metzler ME880's on my V92TC. Now my front tire is in need of replacement but my back tire has about 50% tread left. Isn't this backwards??? If I recall, every other bike I've had would wear back tires faster (almost 2:1) than the front tire. The wear on both tires is nice and uniform. Is there something I should be checking?