At what psi can I travel 65-75mph?

Francesca Knowles wrote:

Me Again wrote:


You seem to think ST tires are something special, when if fact they are just cheap tires that dodge normal tire standards and receive inflated ratings that they do not deserve.

The fact that they are not intended to carry passengers allows them to play the game they do.


Chris

Since I was quoting Tireman9, I presume the first remark is addressed to him and will leave it to him to respond if he thinks it worthy of remarking on.

But I can't leave that second part alone...

No matter how many times it gets repeated in forums like this one, it is NOT a "fact" that ST tires are "not intended to carry passengers".

It's legal in many States for passengers to ride in trailers, and in even more for folks to ride in fifth wheels. Not a single trailer maker/tire maker/regulatory agency imposes any restriction on such use if the trailer has ST tires on it. Since the hazards of bad tires extend to everyone in the vicinity if such a tire blows, every tire approved for highway use must meet the same standards of safety.

ST's are not designed to steer or drive, but to track efficiently. For that reason alone they can't/shouldn't be installed on steered/driven vehicles

the ST tire is special and has received special treatment when it came to upgrading regulations for safety and highway tires...

I don’t agree with your assertion that the ST tire is a passenger tire… the ST is not designated as a passenger tire, and a state law permitting passengers to ride in the trailer doesn’t change its designated use… the designated use as a trailer tire doesn’t prohibit a trailer using them from also allowing passengers… but there is no perception that trailers are passenger vehicles…


There are plenty of references in official documents where they refer to them as other than passenger carrying tires, instead of saying non passenger carrying…

It’s only a play on words but it does make a difference… it has allowed the ST tire to escape the upgraded testing procedures and certification requirements that all the other passenger carrying tires are now required to meet…

One of the arguments presented to the NTHSA to omit the ST tire from the new requirements was they were a trailer tire and not a passenger tire, and they presented little in the way of risk to life, injury, or physical property damage because of it…

“RMA suggests that, under FMVSS No. 139, a passenger tire should be defined as one intended for normal highway service and its size designation typically shown as "P" metric or "Hard" metric and a light truck tire should be defined as one intended for normal highway service and its size designation includes "LT" and is load range "C", "D", or "E".”

So I guess the ST tire is not intended for normal highway service, but that is exactly what they are supposed to be… A HIGHWAT TIRE… that is their normal service… and any tire used on our highways should be required to meet the same stringent standards…

“Several commenters suggested that certain tires produced for specialty uses or antique vehicles be excluded from adhering to the new performance requirements. RMA suggested that the agency exclude temporary spares, various trailer tires, snow and deep lug tires, and bias tires from the applicability of FMVSS No. 139. The TRA asked that special-use tires such as ST, FI, and 8-12 rim diameter and below tires (typically used on smaller, towed trailers) be excluded from FMVSS No. 139 and continue to be covered by FMVSS No. 109. Specialty Tires and CU argued that bias ply tires should continue to regulated under FMVSS No. 109, not FMVSS No. 139 “

“the agency has decided to exclude bias, ST, FI, and 8-12 rim diameter tires from FMVSS No. 139.”

In other words the agency (NHTSA) caved to the pressure of the industry and allow for them to have the ability to produce a low standard, low quality, low priced tire…