Modern Equivalent of Obsolete H78-15 Tire Size

Question:

Hello I have a trailer tires H 78 Dash 15 ST I had to replace them with ST20575R 15’s which were sold to me I bought these last year and I just wanna make sure they were the right ones

asked by: John

Expert Reply:

The modern equivalent to the H78-15 tire size would be 225/75-15.

A 225/75-15 tire would be about 1 inch taller and 3/4 of an inch wider than what you're using now, but I'd say that what you have is close enough to work fine for you as long as the combined load rating of your tires is greater than the GVWR of the trailer.

Next time you need tires, you can move to the 225/75-15 tire size if you wish, like the # TTWSF22515D that you looked at. However, if the tire will see a lot of highway use, I'd go with a radial tire in that size such as part # AM10256. A radial tire will provide a smoother ride and will do a better job of shedding excess heat which leads to longer tire life.

expert reply by: Mike L