Speed and blown tires

GoPackGo wrote:
Regarding 1) above - the load index rating of 117/112 means that if the tire is used in a single wheel application, the load rating is 117. If used as a dually, the load index is 112. Has nothing to do with speed.

From tirerack.com -

"When looking at light truck (LT) or newer Special Trailer Service (ST) tires, there are two load indexes branded on the sidewall, separated by a forward slash. Using an LT235/75R15 104/101S Load Range C tire as an example, the load index is 104/101. 104 corresponds to 1,984 pounds, and 101 corresponds to 1,819 pounds. So what is the true load carrying capacity of the tire? The answer changes depending on the situation in which the tire is being used.

Since LT tires are commonly used on trucks with dual rear wheels, they are branded with two load indexes. The first number indicates the load carrying capacity if the tire is installed on a truck with a single-wheel rear axle, and the second number applies when the tire is used in a dual rear application.

Though it may seem counterintuitive that a tire is rated to carry less weight when working in tandem with another tire in the dual pair, the purpose is to build in additional reserve capacity should one of the two tires fail, leaving the sole remaining tire to carry the load normally handled by two tires."




I would not run ST tires over the historical speed rating of 65 mph without being absolutely sure the manufacturer has rated them to a higher speed - and then it would depend on the tire brand's reputation. I do realize the new breed of ST tires have higher speed ratings and I should have stated that more clearly in my first post.

I just looked and towmax LR-E tires are now rated for 75 mph at the standard 80 psi. You would have to pay me a lot of money to run down the road pulling a heavy fiver at 75 mph on those tires. As I stated above, the first towmax on my rig lasted exactly 1 year - and I run 58-60 mph.

I believe the phrase that applies here is Buyer Beware.

for truck tires yes, the dual load index is for single vs dual axle rating. However I suspect that if you were to query Goodyear, the dual load index is for 65mph vs 87mph. I've never seen a dually trailer axle. and the dual rating applies to a single axle, not a tandem or triple axle setup.

However, if it does apply to dually use, then the goodyear has NO load decrease between 65mph and 87mph.