Quote:
Originally Posted by gearhead
So mechanically speaking, are the increased failures when going over the rated speed due to increased frequency of sidewall flex, belt separation, or ?
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When it comes to tire mechanics I rely on the more experienced posters like Tireman9 for answers. From my point of view, tires are going to start degrading when subjected to speeds greater then what they were designed to resist.
Speed ratings for ST tires have become very controversial since they started using ratings higher than 65 MPH on their sidewalls. Because I don’t have access to confidential TRA manuals I cannot argue with those that do. However, from knowledge of how the systems work, I find it very improbable that the largest tire manufacturer in the world (GY) would introduce a completely new line-up of ST tires and give them a speed rating of 87 MPH without NHTSA approval. Somewhere in that process NHTSA was assured by GY that their new line-up was tested for the 87 MPH limit.
As for a tread separations, who knows, they are normally caused by numerous misuse factors. Sidewall flex is another engineering subject. Each tire design (ST - LT – P) is different and tested for different factors to correspond with their expected usage. However, they can all be used on RV trailer axles. That’s a decision only the trailer manufacturer can make for OE tires.