When Increasing Width of Trailer Tire How Much Frame to Tire Clearance is Lost

Question:

Our Son has an old boat trailer that needs new tires. I have read the questions and answers for going from the 155 size tire to the 175 or the 530 - 12 tire. I did some measuring on the boat trailer. The is no clearance issue with the larger diameter 175 tire fitting in the wheel well. Not sure on the width. One of the answers commented the tire is basically 3/4 of an inch wider. Hoping you can add a little more info for width. For the 3/4 inch larger width is that all on one side, inside or outside split 3/8 inch on each side or does it depend on the rim the tire is mounted on? And If the width is close, should I just the 175 size tire idea and go with the 530 - 12 size tire? Thanks!

asked by: Ken E

Expert Reply:

The extra width of a wider trailer tire gets split in half since the offset of a trailer wheel is zero. So in the situation where you mentioned the extra width between two sizes being 3/4 of an inch that means you'd lose 3/8 of an inch of inner wheel well space.

Ideally you have at least 1-1/2 inches of clearance between the frame rail and the sidewall of the tire.

expert reply by: Jameson C