Upgrading from ST175/80R13 Load Range C to Load Range D Tires on EZ Loader Boat Trailer

Published 11/18/2023

Question:

I have an EZ Loader boat trailer with ST175/80R13 Load C tires . I feel these tire are to lite of a load rating , there seems to be a lot of side wall flex .I would like to upgrade the Load range to a D or E if they are manufactured. I’m leaning towards the Load D tires Thanks

asked by: Frank

Helpful Expert Reply:

Load range D is likely the highest you will find on an ST175/80R13 tire. This is going to be a significant capacity increase over your current tires. Your typical load range C has a max load of 1,360 lbs per tire at 50 psi while a tire like the Karrier ST175/80R13 # AM10210 you looked at is 1,650 lbs at 70 psi.

The higher ply rating will reduce that flexing you have now and also help the tires run a bit cooler which will reduce wear and extend the life of the tires. This tire has a max speed rating of M for 81 mph and also comes with a 5-year limited warranty.

expert reply by: Robin H