AH, I don't blame you on that one man! especially if you don't have at least a covered working area, I've been there and done that too much before. yeah the tape measure works every time with out fail if you A, have someone to help hold it on the other tire, and B can get the steering wheel straight, that's the trick even amounts on each side, so it is doable
good luck getting her done man! hopefully the shop doesn't rape your wallet too hard!
