After blowing trailer tires regularly...

[rickhz]

After blowing tires regularly on a flatbed car hauler I did some research into trailer tires. I was buying the best tires I could, and getting the "Certificates" for them from Discount and Big -O. I was replacing tires with great tread after just a couple trips. I even went as far as to carry two tires as spares since I was blowing them out so often. This was going on for well over a decade.

Turns out that ST tires, and as far as I know ALL ST tires are rated for 65mph max. The speed limit on AZ highways is 75. I was driving 75 to 80. Not one tire salesmen ever asked me how fast I was driving.

Once I learned that trailer tires are only rated at 65mph I cut down my cruising speed to 65 - 70. Guess what... I have not blown a tire since and it's been about three years and thousands of miles.

I'm just passing this on since none of the salesmen I worked with seemed to even consider speed of travel when they were "selling me" new tires for $40 dollar a piece with their "certificates". Someone was losing a lot of money on that deal, and I was losing patience. I really thought it was the fault of the tires... Nope, it was the fault of high speeds, and hot AZ road temperatures.

[Javi]

Yep....

Javi

[CaptnJohn]

Not all ST tires are rated at 65. My Carlisle ST tires are rated at 75, some others are higher. I maintain 63 - 65 99% of the time when I may run to 70 passing. Not going to jinx myself so will not tell you never a problem on a past TT or 5er or the current 5er. 63 is the sweet spot when towing 13,500# for my truck.

[66joej]

Over recommended speed and heat as well as lower than posted sidewall air pressure are among the the chief causes of trailer tire failures. Age of tires comes in there also. We have a great tire expert on this forum who can enlighten.

[rickhz]

Originally Posted by CaptnJohn

Not all ST tires are rated at 65. My Carlisle ST tires are rated at 75, some others are higher. I maintain 63 - 65 99% of the time when I may run to 70 passing. Not going to jinx myself so will not tell you never a problem on a past TT or 5er or the current 5er. 63 is the sweet spot when towing 13,500# for my truck.

I had to look that up for myself and you are indeed correct. I now know which 16" tires to get for my 5th wheel, but it appears that I'm still in the same boat with my 15" car hauler tires.

Thanks for the info.

[JRTJH]

Originally Posted by rickhz

... but it appears that I'm still in the same boat with my 15" car hauler tires...

Carlisle Radial Trail HD tires in 205 75R15 LRC, 225 75R15 LRD and 225 75R15 LRE are all speed rated at 81 MPH

Carlisle Radial Trail RH tires in the same sizes are speed rated at 75 MPH.
http://www.carlislebrandtires.com/ou...adial-trail-hd

[Pmedic4]

I can only give anecdotal stories, but one thing I definitely saw were lots of blow outs when it was hot, versus cool weather driving. Definitely wouldn't be surprised by greater numbers of blowouts in your AZ heat.

[xrated]

Maxxis 8008 ST tires on my T.H. The 235/80/16E are speed rated "Q" which is 99 MPH. I normally run between 63 to 65 MPH, except for maybe a short stint while passing.

[xcntrk]

Do any of you use tire monitoring systems? Granted I realize that in a blow-out situation, a time delayed monitor isn't going to do any good, but in those situations where heat and overpressure lead to blow-out, a tire monitor would inform you BEFORE the blow-out occurs giving you a chance to pull over and check things out.

When I hear somebody struggling with frequent blow-out of NEW tires I think: overloaded, under pressure, or over speed.

[xrated]

I believe a lot of us on here use TPMS systems, different brands, different models, but the bottom line is that if used properly they can serve as a valuable tool for preventing tire issues. I use the Tire Minder Smart TPMS , which of course monitors both pressure and temperature in each tire.

[notanlines]

Not only do we use a TPMS on our rig, but at EVERY stop I walk around to each tire and use my super-duper infrared temperature gauge from Harbor Freight and look at the temperature of the tread. One can look at the temperature almost as fast as one can walk so it doesn't take an concerted effort to speak of. (And yes, y'all have heard me bad-mouth HF on occasion, but I couldn't pass up the $16.00 special)

[CWtheMan]

Speed ratings for ST tires are relatively new. It came about when the USA threatened higher tariff fees for certain tires imported from China devoid of any recognizable speed restriction information, STs were on the list. Until that happened just about all ST tires were devoid of any speed restriction information on their sidewalls. Some manufacturer's advertised their ST tires as having 60 - 62 MPH restrictions in their warranty information. But officially, (when unmarked) all have a mandated restriction of 65 MPH.

The newer tires will have a speed letter at the end of a service description (129/125 L). In this case the L = 75 MPH. The service description 129/125 is not recognized as the official load indicator for ST or LT tires. The ply rating/Load Range letter system is the only recognized load capacity indicator for the ST & LT tires. During the 2007 rules decision making process the service description system was allowed to be put on those tire's sidewalls in hopes the system would become standard for all tires. It has not happened.

Those ST manufacturers that choose not to use the service description method will just mold a speed restriction right on the tire sidewall (Example: 75 MPH)

I don't think it's a tire installers responsibility to inform a customer about his new tire's speed restriction unless they are of a different size or design from the Original Equipment tires depicted on the trailer's certification label/tire placard.

Heat in the tires: If you have a manual device that can measure the heat emitted from your tires you should check them right away and then again 10-15 minutes later. Overheated brakes/drums will dissipate heat into the wheel/tire assembly. You may have a single dragging break so check all of them.

Just a note: A speed restriction MUST be marked somewhere on the tire. If not, that tire will default to whatever the Tire & Rim Association has in their files for that tire design. All ST tires with a DOT on their sidewalls default to 65 MPH. It does not make a difference where they are manufactured or by whom. A tire manufacturer can say otherwise, but, unless it's on the sidewall you can't take it to the bank.