What is the Recommended Tire Spacing on Tandem Axles?

Question:

Hi, I'm thinking about changing out my ST205/75R15 tires to a larger ST225/75R15. I've seen conflicting information about the space that needs to be maintained between the forward and aft tires when moving to a larger size. I currently have just under 5 inches. I believe upsizing would put me at about 3-1/2 inches. What is the minimum recommended space that needs to be maintained between the tires and why? Are the benefits of upsizing the tires worth the trouble? Should I just find a quality tire in the ST205/75R15 and not worry about rotations/miles, ect? Thanks

asked by: David B

Expert Reply:

There are no industry standards for minimum spacing between the forward and aft tires, and the 3-1/2 inches of space you referred to will be plenty. Should you need the larger weight capacity the larger tires offer, you will be fine upgrading from 205/75R15 to 225/75R15. Something else to consider is the clearance between the inside wall of the tire and the trailer frame because the larger tires will be nearly an inch wider, so be sure you have at least three or four inches of clearance there.

There are a number of quality tires available for you, depending on the load range you want. For a C load rating, I recommend the Karrier ST225/75R15, # AM10251, which has a maximum load capacity of 2,150 lbs at 50 psi and fits 15- x 6-inch, 15- x 6-1/2-inch, and 15- x 7-inch wheels. The Karrier tires have a computer-generated tread design which maximizes traction whether the road is dry or slick, as opposed to other radial tires, which may only work best during dry highway driving.

Should you need a tire with a load rating of D, I would stick with Karrier, # AM10256, which also fits 15- x 6-inch, 15- x 6-1/2-inch, and 15- x 7-inch wheels and has a maximum load capacity of 2,540 lbs at 65 psi. Karrier has the same tire with a load rating of E, # AM10303, and that carries a maximum load capacity of 2,830 lbs at 80 psi.

I have included links to video reviews of each tire for you.

expert reply by: Kyle S