Tires - Good insights for one and all!

[dkottum]

And sometimes we have to understand the majority can be right.

[xrvr]

Or just misinformed by a few persistent posters on one side of the issue or another.i think we should rehash this again. I've got my work done for the day and enjoy keeping score. It's a tie so far. Someone had to say it. Does this is make me a troll? Hope not, I'm enjoying the postings.

[Al and Missy]

In my application, the GYMs I took off were rated for 2540# each, a total of 10,160#. GVWR of my 2001 Safari 25 is 6300# and CAT weights showed less than that. Take off 800# for tongue weight (not carried by the tires) and that leaves 5500# on 10160# capacity. I inflate my Michelins to 75psi which gives me the same load carrying capacity as the original tires and 85% margin on carrying capacity. I'm not anticipating any problems.

And thanks to Tireman for sharing so much useful data on here and his blog.

Al

[TheCabin]

Originally Posted by TheCabin

This sounds hopeful:

ST tires: All-steel radial construction is meeting the demand for more carrying capacity - Article - Modern Tire Dealer

Are these considered to represent the low end of the load scale for a commercial truck tire rather than being on the high end of the load scale for a large car tire? And, is there a reputable maker of this "class" for a 15"?

[tifspiff9]

We, too, are looking for new tires but I have seen to stay far away from any China-made tires. The Carlisle Radial Trail RH ST225/75R15 has good reviews online but are definitely made in China. Any thoughts from the other side?

[Tireman9]

Originally Posted by TheCabin

Is there a tire that comes close to being ideal? One that would support at least 30% greater load than an AS rating, hold air for a long time, have low cord shear (single steel cord?) and work on 15" wheels....

Let me know when you find that tire. maybe it will also fit on an "ideal car" that is as fast as a Corvette, Has the load capacity of a 1 ton dually and the fuel economy of a Honda CR-Z (38 mpg).

++++
OK reality here
The load rating is AS decision as they are the ones responsible for selecting tires and suggesting the air pressure which dictates the load capacity. There are lots of tires that can carry 30% more than current AS loads. The problem is they are larger and cost more than AS or you want to pay.
RE holding air Today most tires designed for application on cars have air retention spec of 2% per month or less with many at 1% per month so is this too much loss for you? How much would you be willing to pay for say 0.5% loss rate? I don't hear a lot of complaints on the 1% to 2% rate.

Interply shear is based on science. You could lower this force by designing trailers with passive axle steering similar to what is on many busses, dump trucks and even on RVs. (See the

Freightliner Ultrasteer

tag axle)

Not sure what you mean by "single steel cord". Cord by definition is a multi strand configuration which is needed if you want bending. If you were thinking of making the belts of a series of steel rods you would have other problems as rods don't bend. ( another of those pesky science things)

[Tireman9]

Originally Posted by tifspiff9

We, too, are looking for new tires but I have seen to stay far away from any China-made tires. The Carlisle Radial Trail RH ST225/75R15 has good reviews online but are definitely made in China. Any thoughts from the other side?

I know Goodyear makes some all steel "commercial" tires, so does Bridgestone. You just have to be willing to pay for the extra material in the tire and extra cost associated with making the tire here in the USA.

Now if you want a small size like 225/75R15 with 110 psi capability you will also need to buy some new wheels.


Of course all we need to do is have a vote and if the majority wins then the strength of high carbon steel is no longer 90,000 psi but maybe it will be 180,000 psi.

[SCOTTinNJ]

Originally Posted by Tireman9

Let me know when you find that tire. maybe it will also fit on an "ideal car" that is as fast as a Corvette, Has the load capacity of a 1 ton dually...

How about putting it this way. What would you suggest in a 15" tire on stock rims for a 8800# gvwr trailer? Serious question. My exact trailer spec. [emoji2]

[xrvr]

Maxxis e rated st tire.

[Lance M]

Originally Posted by Tireman9

You may need to know more about tires than the salesman does.

This is very good advice.

[TheCabin]

I am beginning to see that the process for selecting the correct tire is bounded the sales people who have the perfect tire based upon size and color (much like a refrigerator) and the engineer that knows what it should be but cannot build it to those specs. Where are the chemists and physicists?

[Skater]

I'm sure you'll excuse me if Carlisle isn't on my list of tires to use in the future. One was 3 years old, one was four years old, both were inflated to 60 PSI (10 over what AS recommends, 5 short of the max). That was a day I don't want to repeat, and a rough start to our road trip. (I've already discussed this with Tireman, so no need to rehash it for me.)

[xrvr]

Curious, what did the T man have to say?

[CRH]

Which Carlisle tires were those?

[AtomicNo13]

Look like radial trail rh....

[AtomicNo13]

Was that an e rated Carlisle?

[Alphonse]

Originally Posted by TheCabin

Is there a tire that comes close to being ideal? One that would support at least 30% greater load than an AS rating, hold air for a long time, have low cord shear (single steel cord?) and work on 15" wheels....

They're testing it now, should be released as soon as they find it!

https://www.youtube.com/watch?v=96ME...ature=youtu.be

[pappy19]

I personally have never used a Carlisle, but I have friends that will never use them again due to premature failures. Also bad reports from ATV buddies that have had bad luck with Carlisle's. For me, no ST's on my AS ever again.

[switz]

I have a single axle "rail" type large motorcycle (GoldWing at 960 pounds) trailer. The GYM ST tires delaminated multiple times over the years even though the tires were covered. Now using 13" Michelin car tires as the trailer and bike together weigh less than 1500 pounds.

[Tireman9]

A general comment on tire inspection and how it may be able to prevent RV damage due to tire failure if done properly.

There are three basic types of tire failures.

- The least likely is a sudden large impact with some object in the road. This is the least likely and is actually difficult to do. By this I mean to have a tire that is OK with no damage having been done due to excess heat, high load, low inflation or improper repair. It could even be a new tire. You drive over something like a Railroad spike or into a foot deep pot hole or over a 10" chunk of scrap steel that fell off a truck. It has to be large and you have to hit is just right for the tire to suffer immediate failure. I know from personal experience (doing a special test project of tire "blowout") that even driving over a piece of 2" pipe sharpened at one end and standing 2" up in the road with sharp end up doesn't always cut through the steel belts of a tire. Yes you might run over something that cuts the tire but you would see it in the road and hear it hit but most of the time the air loss is not immediate. The good news about this type of failure is that it has a very low probability of happening. I would guess that fewer the 5% and maybe less than 2% of RV tire failures are of this type.

- Next is the belt separation. This is when the tire tread and belts come off the body of the tire. This is usually the result of tire aging and long term cumulative heat related damage that reduces the flexibility of the rubber to the point that rather than bending the rubber develops microscopic crack which do not heal themselves but will grow. Excess heat and tire aging can come from many sources. Even parking in direct sunlight with "tire protectant" spray does not lower the temperature of the tire. Excess heat can accelerate the aging or the tire rubber properties and drastically reduce the tire life. I would expect that if properly diagnosed this type of failure occurs 25 to 40% of the time. The good news is that with proper and frequent tire inspection this can be discovered and the tire replaced before it comes apart enough to cause damage to the RV. I did a blog post just on this topic "How do I inspect my tires" back in Aug 12 2014. You can Google the phrase and find a number of web pages on the topic but many simply are telling you to look at tread depth but this is not sufficient if you want to do a complete and competent inspection. My link included a YouTube video showing the inspection of a tire with belt detachment that has not come apart and the result of the "tire autopsy" I was able to perform.

- Finally there is what is commonly, and incorrectly, called a "Blowout". This is really a failure of the tire sidewall due to excessive flexing from running with significantly under-inflated ( probably below 50% of the inflation needed to carry the load. For Polyester tires (mainly ST and LT type) This heat due to flexing can be enough to reduce the strength by half and in extreme cases even melt the cord. For Steel body tires the bending of the steel can result in a fatigue failure similar to bending a steel paper clip till it breaks. This type of failure may be 60 to 80% of the failures on RVs. The good news is that if you run a TPMS you will get a warning of the air leak and hopefully you will not ignore the warning as too many do with other warning indicators on their dash, and take appropriate action which is to stop and pull over as soon as safely possible. Amazingly some people, even when verbally warned that they have a tire that is significantly under-inflated simply choose to continue to drive off. This has happened to me a number of times. As the saying goes "You can lead a horse to water but you can't make them drink".