How to Determine if You Can Replace ST205/75R15 Wheels and Tires With ST225/75R15

Updated 01/30/2023 | Published 01/28/2023

Question:

Hello, I have a 1976 Airstream Trade Wind. Currently it has 205/75 R15 tires with a 6 on 5 1/2 bolt pattern. I was looking to get new wheels and tires and replace it with this: Karrier ST225/75R15 Radial Tire with 15inch Hi-Spec Aluminum Wheel - 6 on 5-1/2inch - LR E Item # AM32684 Would this fit? Thank you

asked by: Brian O

Expert Reply:

A ST205/75R15 tire size like you have now will have a section width of 8.1 inches and overall diameter of 27.1 inches.

A ST225/75R15, # AM32684 will have a section width of 8.9 inches and overall diameter of 28.4 inches.

So the larger size is 0.8 inches wider and 1.3 inches taller. When considering the height, only half of the height needs to be considered. So, it will be 0.65 inches closer to the underneath part of the fender.

If you have more than 0.65 inches of clearance above the existing tires and 0.8 inches between the side of the tire and the inside wall/frame then the larger size will fit.

This is a common size swap and will most likely work. But to be sure, you will want to measure the clearances.

expert reply by: Scott S