just me wrote:

Butyl rubber then being a synthetic compound and is used inside the tires for better air retention, and can with stand the elements better then regular rubber, is also used on the outside of ST's' also to protect against the elements and sidewall/weathering, or checking and being a proper/better application than the rubber used for LT's. Course they are now using more SILICA in the manufacturing process now. And I guess this helps in many ways.
Am I right in this assumption? Or not. This has not been brought up that I could see.
Thanks again. Very informative

ExRocketScientist wrote:

My interpretation of your response to Francesa is that you are saying if one replaced failing ST tires with truly comparable LT tires, they would likely have just as many problems with the LT tires.....

ExRocketScientist wrote:

......It is interesting to note that frequently when members here seek advice on replacements, they get anecdotal evidence from people who either switched to LT tires or Maxxis ST tires. What you see at the end of the thread is that they have followed suit, however, they have also at the same time chosen a tire with a higher load capacity. I would suspect that the others who provided anecdotal evidence of their choice solving their problems may have done the same (myself included). It may all boil down to your advice (that also comes from FastEagle and several other members here with many miles of towing experience) that you really need to select tires that will give you a 15% margin over your GAWR regardless of whether it is an LT tire made in the USA, or an unheard of brand of ST tire made in China.

ExRocketScientist wrote:

My read from the 700+ page document I linked earlier is that they use either carbon black or silica as the filler in tires. The interesting thing is the effect these material have on the coefficient of static friction and the coefficient of sliding friction. For those of you who aren't physicist like me -- a quick explanation. The coefficient of static friction (when you are not sliding) is higher than that of sliding friction. Once your force along the surface exceeds what the friction force can counteract, you start sliding. Once you start sliding, there is less friction, so things aren't getting better. So you don't want to start sliding to begin with. So enter into the picture anti-lock brakes. The idea of these braking systems is to take you to the point just shy of starting to slide. So in theory, with antilock brakes, you never experience sliding friction. Well tires with silica have a higher coefficient of static friction than those filled with carbon black. There are also differences in the coefficient of sliding friction. But what is more important is that the coefficient of sliding friction actually decreases the more you slide. The problem with the silica filled tires is it decreases at a faster rate than those filled with carbon black.

So on a vehicle with antilock brakes you want silica filled tires; on all other vehicles you want carbon black filled tires.

Trailers don't have antilock brake systems, however, you have an adjustment on your brake controller. If you are good at adjusting it for your weight and the current road conditions, you can get braking relative to your tow vehicle braking that approaches the performance of antilock brakes and would benefit from silica filled tires. On some trailers, you just can't get the brakes to lock, so you would also benefit from silica filled tires. But for those of us who are not that good at the adjustment and can manage to lock the trailer brakes in a panic stop, the carbon black filled tires are a better choice.

The problems is -- when looking at a particular tire, how do you know what it is filled with?

ExRocketScientist wrote:

OK . . . I think I've been a little slow the past few days. It's the K factor!.......So if I got that right . . . I can take it to the next level. The service conditions for trailers are not understood correctly so the K factor for ST tires is wrong.......

ExRocketScientist wrote:

.......The trend in the industry has been to go to bigger and bigger units with more gadgets in them. Perhaps the TRA needs to revisit the K factor......

CapriRacer wrote:

But I will tell you that I see an awful lot of LT tires used in trailer service with failures - and there is one more item that I can't reveal so you'll have to trust me on this - when aI do apples to apples comparisons, I don't see a difference.

CapriRacer wrote:



That is an argueable point. It could also be argued that far too many trailers overload the tire. The situation is terribly unclear.


or perhaps the trailer industry needs to size the tires to cover those differences. After all that's what car manufacturers do.

But, again, the situation is terribly unclear.

Chris wrote:



Or most Montana's with GAWR OF 6750 and tires rated to 3420. Do the math 90 full pounds of extra capacity per axle. Chris

FastEagle wrote:



The RV show at the Jacksonville, FL Equestrian Center opened today. It was also half price day for seniors so we drove out for a look see.

Here is one that confirms none of the major heavy fiver trailer manufacturer's give a hoot about reserve load capacity in their OE tire selection.

Here is a picture of a vehicle tire placard. It’s self explanatory.

Tire Placard


The nice clean tires were easy to read. Goodyear Marathons
rated at 3420# at 80 psi. Isn’t that just GREAT?

FastEagle