Community Forums

Desert Flyer · 10-22-2017, 10:08 AM

I am in process of gifting our 2000 Coleman p’up to our son. He and his girlfriend came over Friday to hook it up and take it out over the weekend. Unfortunately, after closely inspecting the 8-yr old tires, discovering some (probably minor) cracking, I nixed the idea. They threw in their tent and off they went. So yesterday I got three new tires from Discount Tire (spare was original 17 yrs old!). Carlisle Radial Trail HD, ST 175/80R13, load range C (1,360lbs). The thing is, I see now the speed rating is up to 83 mph or so! Wow! It used to be only 65 mph. Now, I can’t ever see going that fast but it sure is easy to go over 65 when pulling a p’up. Tires must have been advancing over the past few years now. The old tires were Maxxis M8008...we’ll see how these Carlisle tires made in China do over the new few years.

nineoaks2004 · 10-22-2017, 07:20 PM

remember the tires are still made in China and the Chinese tires do not have a great following. I would tell them to keep it around 60 or lower.

Tireman9 · 10-22-2017, 07:32 PM

Quote:

Originally Posted by Desert Flyer

I am in process of gifting our 2000 Coleman p’up to our son. He and his girlfriend came over Friday to hook it up and take it out over the weekend. Unfortunately, after closely inspecting the 8-yr old tires, discovering some (probably minor) cracking, I nixed the idea. They threw in their tent and off they went. So yesterday I got three new tires from Discount Tire (spare was original 17 yrs old!). Carlisle Radial Trail HD, ST 175/80R13, load range C (1,360lbs). The thing is, I see now the speed rating is up to 83 mph or so! Wow! It used to be only 65 mph. Now, I can’t ever see going that fast but it sure is easy to go over 65 when pulling a p’up. Tires must have been advancing over the past few years now. The old tires were Maxxis M8008...we’ll see how these Carlisle tires made in China do over the new few years.

ST tire load / inflation formula has not changed since the speed was limited to 65 mph.
IMO any speed over that is for marketing purposes or to avoid import duties.

There is no new magic and it is still the air pressure that supports the load. If there had been some new rubber or construction developed to suddenly allow a 10 or 20 or 30 mph increase in operating speed why hasn't that construction put in top of the line LT tires?

Desert Flyer · 10-23-2017, 09:01 AM

Perhaps it is the other way around...the advanced construction of modern high speed passenger and LT tires trickling down finally to ST tires?

JohnBoyToo · 10-23-2017, 09:08 AM

Agree, if it were just a marketing ploy, the lawsuits would be quick to land

I will trust the engineers that do this know more about it than me and that the technology has improved...

but if Tireman9 says no, I will submit to his expertise, so guess we should buy stock in attorney groups

Desert Flyer · 10-23-2017, 09:55 AM

The Carlisle HD was made to replace the RH, which was apparently only mediocre/average. Internet reviews this past year seem to be more favorable than not on the new HD and many put them on par with Maxxis. Time will tell. Also, Goodyear has their new Endurance tires too but those are for larger, heavier trailers. Many are recommending that anything over p’up size should upgrade from load range C (50psi) to load range D (65psi).

Tireman9 · 10-23-2017, 03:45 PM

I do believe the "new" ST tires are better than the "old" designs. I just have problems with the speed claims without any adjustment for load & inflation.

It just isn't logical to have two tires, one "LT" and one "ST" with similar speed and identical inflation but one having significant more claimed load capacity.

Only answer I ever got when I asked is the claim that the torque on motorized vehicles is the reason. If that were true we would have different load ratings based on tire position on a vehicle i.e. driven vs non driven but we don't

Desert Flyer · 10-23-2017, 06:55 PM

I wonder if number of belts and sidewall construction enter into that. I believe the STs have a pretty stiff sidewall, not at all suited for vehicles and cushy ride.

Tireman9 · 10-25-2017, 04:48 PM

Since it is the air that supports the load how can two tires of the same size and with the same inflation have a 10% to 20% difference in load capacity?

FastEagle · 12-11-2017, 10:33 AM

The TRA is an overseer of many things, but, it's still the individual tire manufacturer's responsibility to insure a tire's speed rating is justifiable. They must provide the DOT with certified testing results.

A tire's sidewall information will tell you what the basic building materials are. It will even number them. However, they never mention size. Probably confidential. Logic would seem to support larger cording sizes as being able to provide more load capacity at a given PSI than smaller sizes.

Some tires are more durable than others because of "add-ons" like sidewall protectors, an added steel belt or some sort of overlay or wedge. All good for a chance at lasting longer but none add strength in load capacity.

nineoaks2004 · 12-12-2017, 07:22 PM

Those Chinese tires are known to tear apart at higher speeds, I keep mine below 60 to be sure also I check the air pressure prior to any trip and berfor heading home..

Shadowcatche · 12-13-2017, 06:55 PM

For our teardrop I ditched the ST tires and switched to Michelin passenger car tires each of which has a weight rating for the entire trailer.

JohnBoyToo · 12-13-2017, 06:59 PM

for a teardrop you can probably get away with a car tire,
but I'd never put car tires on a real trailer or 5th wheel...
at the very least do an LT tire so the sidewalls are not mushy and make the rv dance side to side...