Originally Posted by 76Argosy
I said I would report what response I got from Cooper Tires on the ST vs LT issue. Here goes. Cooper sent me an email with a phone number to call. The customer service rep at the number put me on hold and got a gentleman to talk to me who has years of experience actually building the tires and is a trailerist, also. Yes, there is a definite difference between Cooper LT and ST tires.
However, it is not a "safety" difference as long as the load rating is correct for your trailer's gross weight when towed. Both ST and LT tires can be safely used for trailers. The difference in construction is this: Cooper ST tires are basically a tire that combines passenger car tire construction techniques, with heavy duty truck tire fabric and cord materiels. This results in an ST tire having a high LT type load rating with the lower air pressure requirements and soft, shock absorbing sidewalls of a passenger tire. There is also extra UV inhibitors and oils added to the rubber to help in storage. This is much easier on the suspension and other components of the trailer on bumpy roads than the stiff sidewalls and higher air pressure of the LT tires. As far as tire safety is concerned, he stated that is up to the trailerist and how he maintains the tires, keeping the proper air pressure in the tires, and choosing the correct load rating. He stated LT tires have an advantage because of the larger choice of tread patterns and number of sizes available to choose from to suit the conditions you are towing in, such as snow, unimproved roads, etc. He also stated that it is imperative to not allow the trailer to rest on the tires in the same spot for months at a time in the off-season. This causes the fabric cords in the tire to take on a flat "set" which can then cause some of them to actually break apart when you next take the trailer out on the highway. This can cause complete tire failure. He stated the best thing to do is to store the trailer on jacks with the tires in the air, or removed completely. This last information was of concern to me since I only have "stabilizing" jacks and cannot lift the trailer enough to take the load off the tires without serious effort. At any rate, that is what Cooper Tires has to say on this subject.
But are not Cooper's comments about ST tires having "soft shock absorbing sidewalls of a passenger type tire" the opposite of what Andy is saying about ST tires having "Greater sidewall strength" to cope with the side loads of turning a dual axle trailer?
All so confusing! What Andy has said is more typical of the comparative comments I have read elsewhere.
Having said that, I have so far been extremely happy with the 16"LT tires I put on last year to replace my 15" ST's !
Hoping that will continue, but this is indeed a controversial subject, and my fingers are still crossed hoping I will not later regret making the switch!
I have to admit that my decision was based largely on other folks experience as reported on this forum - that, combined with my own less than stellar experience with ST tires!