Question:
What is the difference between 8.25-15 and 7.75 -15 trailer tires? Will they interchange on the the rims? Thanx
asked by: Steve
Expert Reply:
The tire sizes you mention are considered to be obsolete sizes. The 8.25-15 tire would have an 8-1/4 inch width and a diameter around 28-1/2 inches. The 7.75-15 tire would be around 7-3/4 inches wide with an approximate diameter of 27-3/4 inches.
The closest modern tire size to the 8.25-15 would be a ST225/75-15, available in bias ply load range D as part # AM1ST96, or in radial load range D as part # AM10256 or load range C as part # AM10251. A ST225/75-15 would be about the same diameter but about 1/2 an inch wider than the 8.25-15.
The closest modern tire size to the 7.75-15 would be ST205/75-15, available in bias ply load range B as part # AM1ST91 or load range C as part # AM1ST92. It is also available in radial, load range C as part # AM10244. The ST205/75-15 would about the same diameter and 1/2 inch wider than the 7.75-15.
The tires you mention as well as the ones I recommended can all be used on the same sized rim.
Be sure to always keep your trailer tires inflated to the maximum tire pressure stated on the tire sidewall. Under inflated tires lead to heat build-up and premature tire failure.
I have provided links to the tires mentioned above, as well as a link to our Trailer Tire FAQ page.
expert reply by: Mike L

Have a question for the experts? click here.
Products Referenced in This Question
Product Page this Question was Asked From