See the thread in the wheels/tires forum: https://www.6speedonline.com/forums/...ad.php?t=70229

 

You have to get the actual tire specs and compare the dimensions, often a 305 can be as wide or wider than another companies 315.

Also in the meantime if the insides are not "corded" you can have them swap side to side to get more life out of them. I do that all the time especially with the track tires. The tread directionality doesnt matter unless it is in the rain. ie MPScup tires.

 

I agree with Tom on that. I tossed too many tires before learning about that. Tom, hope you had a good time @ Sebring this weekend.