Last spring I decided to replace my 5 year old load range D Goodyear marathon tires. I went up a load range to E and after a little research I went with the Kenda Karriers 225/75/15. Granted I've only put 1000 miles on them so the jury is still out. I will say that the Kenda E's were quite a bit heavier than the GM D's and the sidewall stiffness was night/day. One disappointing thing about the Kendas was the tread width was 3/4'' less than the Marathons along the top. The Kenda E's have no bulge and the towing experience with an E rated vs D rated tire is significantly better and they seem to hold pressure better than the GM D's. Our camper is 9250lbs loaded. A few facts about Kenda; they've been in business since 1962 and they make automotive tires [truck, car, SUV], bicycle tires, powersport tires and turf/trailer specialty tires. Anyone who has a golf cart, carryall probably has Kendas on them. I have them on our boat trailer as well. They are produced in Taiwan, Vietnam, China and they have several facilities in the US. I am not affiliated with Kenda in any way shape or form. All tires get good/bad reviews. I went with the Kendas because the price was right at the time.