Poor choice of tires. Motorcycle tires are easily 2+ times the cost of a car tire and rarely last more than 5-10k miles depending on usage. REALLY hard compound tires will go 15-20k and are sometimes less expensive but you give up grip in the process. Not to mention the rounded profile necessary for a bike to lean will serve only to focus wear on the center of the tire in an auto application so you're spending more money, for less life, and wasting 2/3's or so of the available tread.