Tire Ratings
Correct me if I'm wrong, but aren't all tires of the same type (ST/LT) and the same size (225 75R15) and same load range (C,D,E) rated just the same (as to weight capacity) regardless of manufacturer?
Forum Discussion
JIMNLIN wrote:
If I understand the question a example is a Provider and a Carlisle ST235/80- 16 E has a 3520 lb capacity.
The same size Maxxis and Marathon ST235/80-16 E has a 3420 lb capacity.
This is true and there is still another load capacity not mentioned, 3500#. There is another FMVSS standard that addresses this subject. In part, it says that when a particular tire size is manufactured with multiple load capacities they will all default to the lowest unless individual documentation is provided with the vehicle.
Of course to do that the vehicle manufacturer would have to start advertising tire brands and that don’t often happen so when there is a conflict such as 3520# tires on a 7000# GAWR axle the vehicle manufacturer will just build the weights down to a 6750# GAWR axle so the defaulted load capacity will work.
Because of the way tire industry standards are written a RV trailer manufacturer can provide NHTSA a blanket letter stating they only use 3520# tires on 7000# axles and list the axles as 7000# GAWR. Tire industry standards places the responsibility in the hands of the installer to insure the replacement tires are equal or greater in load capacity when compared to the Original Equipment tires. That means “read the sidewall”. But you’re still going to find Maxxis replacing TowMax.
