This is a cut and post from another forum, but I thought it would make for good discussion here since it comes up quite often.

Regarding the speed rating of trailer tires and to be mindful of watching your speed, or knowing your limits:

I was actually quite mindful of the speed rating on my trailer tires. they were Kenda LoadStar ST145r12 LRE (10ply) which replaced the LRD (8ply) orignals that blew out on the road.

the original tires ad a 75mph speed rating (Service index followed by the letter "L" indicating the speed rating of 75). one of these blew out on a hot day at 65mph. in all honesty, I'm thinking my father in law didn't check the pressure, and that's why it failed.

the Kenda LoadStars are advertised as a 65mph speed rated tire (according to etrailer). I ran them at 70mph, but brought my IR gun along to keep an eye on tire and bearing temps. on the road, the tires, rims, and bearings were always 113-117°F, with the ambient temp in the low to mid 90's. checking the pavement next to the tire (when stopped) the tires were running essentially the same as the pavement - within a few degrees anyway. this settled my mind about exceeding the speed rating.

I'm guessing by upgrading to the LR-E tires, I bought some headroom with regard to speed with the increased load carrying capacity of the tire. with the 10 ply rating, the tires weren't so near to the max load as were the 8 ply tires.

I have no reservations running those tires at 70mph. I considered upping to 75, but with two kids in the back and ambient temps in the low 100's (104 at wasta, to be exact), I didn't feel like pushing my luck anymore than I felt I already was.

 

I think in addition to temperature and load, there may be other factors that limit speed ratings such as the force generated on the perimeter of the tire as it rotates. It has been too long since college physics and I don't know how large a role they play in tire design. My guess is going with a higher rated tire may also would cover that.

Interesting topic as there is no way to actually know how much is gained other than carrying capacity.

My tires mirror yours in terms of temperature.

Steve

 

just to add a point.

some blow-outs are not from load or heat.. but punctures and ply damage from pot-holes

so a tire pressure monitor is helpful for punctures.. I hope Santa reads this. (hint)

but NOT ply damage. ( I think )

Its not possible to cover everything.. like accidents , Life Happens.


Travel Safe.
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All very true.

Centripetal force must play into a tires speed rating. Imagine how much force there is on some of these little tires at interstate speeds.

I agree, too, that you can't control everything. A road hazard is what it is. Sometimes you can miss a pothole sometimes you can't, and that can easily cost you a tire. One should just be aware of the things outside of your control and be mindful of the things over which you have some degree of control.

 

I take pretty good care of my tires, trailer tires especially. I check and set the cold pressure to the sidewall max before leaving on every trip, keep them covered when parked at home and use a TPMS while traveling. The ONLY thing I am guilty of is running my ST tires above their 65 MPH speed rating, I sometimes cruise at 70 MPH.
On my old toyhauler that scaled at 9,500lbs typically (11,300lb GVWR) that was specced to run Load Range D tires I ran LR E ST tires. I suffered 3 simultaneous tire failures at the end of a 210 mile tow on a 95 degree day. On that day I did not exceed 65 MPH at all but 3 of 4 tires developed belt separation that resulted in the tread face becoming rounded partially around the circumference and some tread chunking on all 3 tires. No loss of air in any of the affected tires and we didn't find the damage until we were setting up camp at our destination. There was no damage done to the trailer at the wheel wells but the vibrations from the deformed tires and chunking rubber broke the refrigerator coils and knocked some wire connections loose on the convertor. The Westlake LR E tires were 2.5 years old.
On our current TT we just had a 2 year and 50 week old Power King LR D tire fail internally, again no loss of air and luckily no trailer damage this time. This latest failure is detailer in this thread here. https://www.ford-trucks.com/forums/1...ts-please.html
I am of the opinion that moving up a load range won't buy you any room to run at higher speed than the sidewall rating indicates. I am looking at other options to allow for safer operation and longer life as the linked to thread discussion shows. I just don't think the China made trailer tires we are stuck with these days have any excess capacity in either weight or speed ratings and are pretty much sub-standard as to what we are used to seeing in typical car and truck tires.

 

Given the frequency with which ST tires fail, it is hard to conclude other than they are manufactured to a lower standard than LT truck tires. The exact whys and wherefores I suspect have to do with industry data on how seldom the average towable is used and how few miles it travels each year. Perhaps it is something like, "let's build tires that last long enough to get the average owner through the warranty period"!

Just my thought on what is obviously a recurrent problem for RV owners.

Steve

 

I just put Carlisle Radial Trail HD tires on the 5th wheel. They are speed rated M, 81 mph. Discount Tire offers a 3yr replacement warranty which I bought as well. 3 of the 4 tires they replaced had started to separate and all were just under 3 yrs old.

 

Part of the blow out trend with ST tires might be how they're used....sitting for long periods of time and becoming flat sided, often loaded to the max.

After seeing so many blow out stories, I got a 2nd set of wheels and bought slightly higher load rated LT tires. I take my good tires off and put them inside the camper during the "off" season. The old ST tires just keep the camper off the ground when not in use.

 

Lets also get them balanced.

 

So on a camper forum they are really talking up the Carlisle tires.


It looks like to me LT tires in the 15" rim are not strong enough for big campers so I am going with ST probably Maxxis but I am interested to know if the Carlisles are decent.

 

I saw the same issue with 15" tires as you're seeing so I got 16" rims from etrailer. You should be able to find higher load rated 16" LT tires.

 

I would do it BUT the boss like the rims so to appease her I need to find a 15" solution.

 

Ha! ...I hear ya !

 

It looks like the Carlisle tires are available in a 10ply with a 81mph speed rating.
Seems like that would be hard to beat for the price

Tire Details - Discount Tire Direct

They did have one about $20 cheaper, but I've never heard of them.

They also have the maxis which are $10 more, but don't list the speed rating.

I've got Carlisle tires on my little cargo trailer and haven't had a lick of trouble with them. It's an old pop up camper that we tore down. I've used the heck out of it and overloaded it several times, but it doesn't go real far anymore either. But, the tires are more than 14 years old now too. Before I got it from my dad, it went from Iowa to Oregon and back, then it made about 4 trips from Iowa to south Dakota when we moved back in 2002. Still has those same tires.

I can't badmouth Carlisle....

 

I have some guy on the other forum trying to tell me Michelin LTX M/S tires E Rated on my Ex are not LT tires but car tires.