No, these are way too big. I don'T think a 4.50x18 would fit in the stock swing arm even if you had the correct rim. A 4.00 in the rear is about as big as you can go. The stock 3.25 in the front is pretty tight. Rim sizes are matched to the tire. You will change the bike's handling in a bad way if the tiire-rim do not match. There are a lot of threads on this site that discuss this.