ST Tires changed to LT series tires

[dayle1]

Originally Posted by FastEagle

The reason for not authorizing replacement tires from other designs is all about vehicle certification. Because the vehicle manufacturer has used a particular tire size and design and said it's appropriate on the certification label is seen as binding by tire manufacturers. They cannot control the actions of all retailers handling their products but they, themselves, will not recommend replacing a Original Equipment ST tire with anything but another tire deemed appropriate for trailer service. That includes LT tires designed for “Regional Service Trailer” (RST).

Here is a lesser known tire manufacturers wording about industry standards for replacement tires.

Cooper Tire & Rubber Company - Tire Selection



Look at it objectively. Once an owner strays from following the vehicle manufacturers recommendations for tire replacement, who is going to take the fall for unforeseen failures because of the fitment?

The Cooper info never uses the word 'required' but uses the word 'recommended'. In addition, there is a section titled 'Tire mixing' and again 'recommends' against using different sizes, load ranges and type of construction. But they do not say there is a requirement that mixing cannot be done. The implication is that they understand that there is no requirement to use a specific tire, all they can do is recommend that owners follow the tire sticker.

As for as straying from the 'manufacturers recommendation', there is little benefit in using an ST tire from the majority of tire manufacturers, the owner or his insurance company will end up taking the 'fall'.

[FastEagle]

Originally Posted by dayle1

The Cooper info never uses the word 'required' but uses the word 'recommended'. In addition, there is a section titled 'Tire mixing' and again 'recommends' against using different sizes, load ranges and type of construction. But they do not say there is a requirement that mixing cannot be done. The implication is that they understand that there is no requirement to use a specific tire, all they can do is recommend that owners follow the tire sticker.

As for as straying from the 'manufacturers recommendation', there is little benefit in using an ST tire from the majority of tire manufacturers, the owner or his insurance company will end up taking the 'fall'.

Maxxis Said; "Always choose the original size or the size recommended by your manufacturer when replacing your tires. Replacing tires of different speed ratings, sizes or construction could lead to improper tire performance, tire failure and accident, causing possible serious injury or death."

Maxxis Automotive Tires Important Safety Information | Maxxis Tires USA

[aether_one]

Originally Posted by FastEagle

You support an owners decision to make a radical design change not supported by tire industry standards?

Owners have been doing that on their cars almost as long as cars have existed.

[FastEagle]

Originally Posted by tfryman

Owners have been doing that on their cars almost as long as cars have existed.

The person that was quoted to is a tire engineer. He often does seminars at various venues.

[monkey]

I would have gone with LT's,,, but they are Very rare now days in a 15" size.(as far as E rating anyway) So I replaced the D rated china bombs for E rated Maxxis . So far I am Very Happy with them ! (and response from Maxxis to my questions) I still have the email stating that "ST" tires rated to 65 mph is a Government issued thing... Maxxis rates their tires (mine) to 99mph.. That being said,,, again the ST rating is 65 mph per big brother... Will you see me pulling my 5vr at 90+mph ??? HECK NO !!!! Unless the world is collapsing then all bets are off... I just wanted a tire to safely run 68-70 mph because we are usually time limited on vacations,,, on long mile interstate runs... My truck/trailer combo feels very comphy to me,,, and for what its worth,,,,, I pull doubles 100K miles a year...
Monkey

[Tireman9]

Originally Posted by monkey

I would have gone with LT's,,, but they are Very rare now days in a 15" size.(as far as E rating anyway) So I replaced the D rated china bombs for E rated Maxxis . So far I am Very Happy with them ! (and response from Maxxis to my questions) I still have the email stating that "ST" tires rated to 65 mph is a Government issued thing... Maxxis rates their tires (mine) to 99mph.. That being said,,, again the ST rating is 65 mph per big brother... Will you see me pulling my 5vr at 90+mph ??? HECK NO !!!! Unless the world is collapsing then all bets are off... I just wanted a tire to safely run 68-70 mph because we are usually time limited on vacations,,, on long mile interstate runs... My truck/trailer combo feels very comphy to me,,, and for what its worth,,,,, I pull doubles 100K miles a year...
Monkey

Sorry it's not "Big Brother" that says 65 mph for ST tires. It is fundamental tire engineering. The reason ST type tires are rated for higher load capacity than an identical size & inflation LT tire is because the load formula used to generate the Load & Inflation table numbers is based on a design limit of 65 mph.

The recent change to applying "Speed Symbol" to ST tires was done for political not engineering reasons. Some imported tires were being "dumped" into the US market (artificially lower pricing). Import duties (taxes) were being applied to some tires but exceptions were made and IMO some folks involved with importing low cost ST tires managed to "sell" the idea that tires with speed ratings should be exempt from the import tax.
Then marketing types decided that offer a higher speed symbol might increase sales by implying the higher speed rating tires were somehow better than a tire with a lower speed rating.

If you want to believe there was some magic tire construction features that were applied almost overnight to ST tires to give them 20% greater load capacity than a comparable LT tire have you asked yourself why the same magic tire engineering hasn't been applied to P type and LT type tires to give then an extra 10 to 20% load capacity?