If you really have motorcycle tires on car wheels on your car, you have a problem. I bought a T-Bucket from a friend. It had been in storage for a long time and all the tires needed to be replaced. I was having new rear tires mounted and as I was waiting, I told the sales guy I was going to put motorcycle tires on the front and asked if they sold them there. The sales manager butted in and said "You can't put motorcycle tires on car wheels." I told him I couldn't find car tires for the 4" wide front wheels, and I was not going to buy new front wheels. I won't bore you with the long story that followed. Here's what you need to know.
http://www.goldwingfacts.com/forums...ferences-between-car-motorcycle-rim-tire.html
You can put a car tire on a motorcycle wheel (could be difficult), but it can work. Look at the illustrations in that link and you will see why you do not want motorcycle tires on car wheels. There are several issues. The sizes are different.....a 15" car tire diameter is not the same as a 15" motorcycle tire diameter....not even close.
I ended up with Mickey Thompson front tires, made for 4" wide car wheels. I think they are rated for 130 mph.
You need to check this out. It's a really big deal. Good luck.