On my TR4 I am running 205-65-15's on Panasport wheels. I do not have any problems with tires rubbing front or back and I have converted to tube shocks in the rear. There is a lot of room for the tires. But the three areas you will need to pay attention to are 1)the width of the rims you are using and what will fit on the rims, 2) wider tires will also stick out beyond the fenders a slight amount and 3) determine the total diameter of the tire you have compared to the tire that you want to put on. If you don't match the diameters then your speeometer will be thrown off. Number 2) is not a problem except for throwing rocks and mud , etc.on the outside of the car. My car looks great with the wider tires and I have to say it rides and corners so much better. With the higher speeds on freeways I like have more tire on the road.
Charley Fitch
