02/12: New Tire Discussion on Woodalls: LT versus ST and more.

[Gene]

I don't believe Macs come with flash player. I have had some strange results where I don't get the right page lately. Maybe it will pass.

Gene

[ROBERTSUNRUS]

Hi, I'm no-where as long winded as a few of you are, but my trailer came with five Goodyear Marathons that were made in Canada. I now have one left and it is my spare tire, on a steel wheel, that has never touched the ground. Due to where I was when I needed to replace these Original Marathons, [made in Canada] I now have one Carlisle and three, "Made in China" Goodyear Marathons. Maybe China is being blamed for Canadian tires too. Two of my Canadian Marathons got sidewall bubbles at around 3 1/2 years old. The other two started to separate, on my Alaska trip and they were about 7 years old. In this limited time, in all kinds of weather, and many thousands of miles, I haven't had any problems with my Chinese tires.

[Beginner]

Back when the Tires...Tires...Tires... thread was going (and I stated this in a post in that thread) I managed to get the NHTSA Tire Engineer on the phone and talked with him for a while about tires and more importantly tire testing. He invited me to read the testing criteria for both the ST and LT tires. They are on the NHTSA web site.
His statement about tire ratings was that the speed rating was an all encompassing acid test of how much heat a tire could stand and still be reliable. ST tires are 65 MPH tires. LT tires are generally 99 MPH tires. Do you drive 65 MPG or less always?
How much sence does it make to overinflate a tire when you intend to run it past its stated design limits? Common sence should indicate that a 65 mph tire will have cheaper rubber compounds used in its construction.
I weighed my trailer on a CAT scale and used that occasion to properly adjust my weight distribution hitch so that my tongue height had between 3100 and 3200 lbs on each axle(both tow vehicle and trailer).
The ST tires that failed on my trailer were load range D and had 1600 lbs on them. I ran 60 PSI in them, more than enough for a load of 1600 lbs according to Good Years inflation chart.
I had a tire pressure monitor on the tires when they failed. I also had to add air to the tires each time I wanted to use the trailer(the TPMS told me the tires were low). I carried a compressor to do this.
You can assign all the letters you want to try and quantify this thing but the fact remains, ST tires give trouble when loaded past 50% or so of their weight capacity (I know this a jump), check the old thread. The ones having the most trouble were those of us with the twin axle longer, heaver trailers.
ST Load range "E" tires when inflated to the value in the load/pressure chart still give trouble, even when overinflated 10 psi.
LT tires when inflated to the value in their load/pressure chart do not.
I run 60 psi in my Load range D BF Goodrich Commercial T/As which is proper for the load on the tire (according to the CAT scale).
Give it up, either go 45 mph (remember the Do not exceed 45 mph on the U Haul trailer fender) or buy better tires. Even U Haul puts LT tires on their trailers now.
No amount of brow beating will make the ST tire better.
Its not our fault the ST tires fail.
Those of who have gone to the LT tire have stopped having trouble, period.
Beginner

[Kosm1o]

I was at my tire dealer and looked at GYMs to see where manufactured. All tires were made in China. Also, cost of 15" Michelin is not much different than GYM. Many folks have used 15" Mich M/S for many years with great success. Never heard or read of a tread seperation with one.

[LI Pets]

Ok, so I want to keep my 15" wheels,

What LT tires are there to choose from?

I don't find any.

[Gene]

Originally Posted by LI Pets

Ok, so I want to keep my 15" wheels,

What LT tires are there to choose from?

I don't find any.

And that's why many of us have gotten 16" wheels. 15" used to be a common tire size, but now that wheels have gotten so big on newer vehicles, 15" tires are getting rare in the proper size for Airstreams.

I don't know whether Discount Tire has gotten to Long Is., but check their website for 15" LT tires in the proper size. You can also check Tire Rack. Or check major manufacturers' websites. That should show you what is available. You may have done all this. Some people have posted they found some 15" tires, but if I recall correctly, they were P, not LT, tires and didn't support enough weight.

I realize replacing 7 wheels is pretty expensive, but probably cheaper than the damage tread separation can do.

Or you can buy a 25 or 27 footer as you thought you might about a year or so ago and get it with 16" wheels right away.

Gene

[scotty4040]

Many people jab reported going to a 235-75-15xl, which is good to 2200 lbs. That's what I am planning for my 74 Overlander.

[slowmover]

That thread isn't so long if one keeps reading to the following:

- CapriRacer [OP] [tire engineer]
- ExRocketScientist [amateur]
- Jimnlin [commercial operator]
- TM9 [tire engineer]

There are some old animosities playing as well, so other posts aren't as informative (direct-to-the-point). Jimnlin is the touchpost for understanding.

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Slip Angle & Lateral Force Post

CapriRacer

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What happens to trailer ride quality when you run a tire with a higher load rating?

CR:

If your only change is the load rating - nothing. If you add inflation pressure to get a higher load carrying capacity, then the ride quality diminishes - but not enough for you to worry about. It would be more uncomfortable to ride in (You're not going to ride back there, are you?), but it wouldn't (or shouldn't) be the difference between breaking things and not.

And lastly, if you use a larger tire size, but the same pressure, you get no change in ride quality, AND an increase in load carrying capacity - Win/Win!!

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TM9: A tire is considered to be "flat" if it has less than 80% of the minimum recommended inflation. (65-psi down to 50-psi)

Doesn't make any difference what type tire we are talking about P, LT, ST or TB (TB is Truck Bus or what you see on Class-A MH)

-------------------------------

CapriRacer:

Just so everyone who is following this thread understands - as a tire engineer, I view the change from an ST225/75R15 Load Range D to an LT225/75R16 Load Range E as an 18% increase in load carrying capacity.

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TM9

COMMENT ON TEMP

TM9


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TM9

FIRST STEP ON TIRE ANALYSIS:

TM9


Looking fairly simple so far. Go up in size for load margin increase. Move from ST to LT. Run at maximum sidewall pressure. Match rim width to tread width (narrower is better). Shallower tread depth. Highest speed rating.

The harder part is Load Range. I'm not in favor of 80-psi tires if 65-psi tires could be fitted. But on an SS trailer the suspension can be modified for a better ride (wheel travel; shocks, equalizers, etc), and concerns about beating up the trailer aren't the same.

The BFGOODRICH Commercial T/A and BRIDGESTONE Duravis 250 are looking good (for 80-psi tires) in 16" or 17".

But individual wheel weights, first (as side-to-side [cross axle] and front-to-rear [axle-to-axle] will not be the same; one tire may be holding as much as 30% more in some instances) so load margin is not just a matter of axle average weights (8k GVWR is not a 2k tire plus 15%, but the heaviest wheel position plus that percentage)

As well: Perfect wheel alignment. Balancers. In-tire TPMS. No brake drag or wheel bearing misadjustment. The usual.

Etc.

.

[r carl]

Originally Posted by LI Pets

Ok, so I want to keep my 15" wheels,

What LT tires are there to choose from?

I don't find any.

Yokohama*RY215

Continental*Vanco 2

[slowmover]

Anyone have a link to an expensive $$$ tire damage thread on this site? Pics and dollar numbers and outcome? (Where are you, 2Air?). Aluminum trailer owners have some serious dollars tied up in this concern.

[richinny]

this google search should help locate some tire damage photos:
pic of tire damage - Google Search

[r carl]

Originally Posted by ROBERTSUNRUS

Hi, I'm no-where as long winded as a few of you are, but my trailer came with five Goodyear Marathons that were made in Canada. I now have one left and it is my spare tire, on a steel wheel, that has never touched the ground. Due to where I was when I needed to replace these Original Marathons, [made in Canada] I now have one Carlisle and three, "Made in China" Goodyear Marathons. Maybe China is being blamed for Canadian tires too. Two of my Canadian Marathons got sidewall bubbles at around 3 1/2 years old. The other two started to separate, on my Alaska trip and they were about 7 years old. In this limited time, in all kinds of weather, and many thousands of miles, I haven't had any problems with my Chinese tires.

You were forwarned, if you ever have a problem dont curse or cry.

[ROBERTSUNRUS]

Originally Posted by r carl

You were forwarned, if you ever have a problem don't curse or cry.

Hi, don't worry about me. So far my Chinese tires have done better than my Canadian tires. I have never had a tire fly apart, a tire blow out, or even a flat tire. [doesn't mean that I never will] I'm very observant and spotted all of my tires problems before disaster. I have posted pictures and explanations of all of these tires on this forum; Nothing to hide.

[LI Pets]

I've had made in China ST's on since beginning of '06, have close to 40,000 they have enough tread to go more but due to age I'm replacing.

The stories we hear hear are only the failures the folks that have no issues likely don't report.

Except for Marathons I'll buy another set of ST (or LT if I can find 15") made in China.

I'm waiting for the Importer of that new brand to contact me when they arrive as I said if the price is good I'll buy 'em.

[slowmover]

Originally Posted by LI Pets

I've had made in China ST's on since beginning of '06, have close to 40,000 they have enough tread to go more but due to age I'm replacing.

The stories we hear hear are only the failures the folks that have no issues likely don't report.

Except for Marathons I'll buy another set of ST (or LT if I can find 15") made in China.

I'm waiting for the Importer of that new brand to contact me when they arrive as I said if the price is good I'll buy 'em.

So you haven't read the Woodalls thread? (the subject of this thread).

[boondockdad]

'nother GYM failure yesterday... that makes FIVE since factory new purchase 10/2007

Here's the history of each Goodyear Marathon failure:

03/2012 SSR. Tread separation. Replaced with Commodore
07/2011 SSF. Tread separation. Replaced with Carlisle
12/2010 CSR. Tread separation. Replaced with GYM
03/2009 CSF. Tread eject. Replaced with MAXXIS (~$2,500 damage)
03/2009 SSR. Tread eject. Replaced with GYM (~$12,500 damage)

After the 3/09 incident, I installed TPMS and was able to catch subsequent failures before damage occurred.

I'll be upgrading to 16" rims/Michelins once the "Rims & Rubbers" coverage clause is added to the current PPACA, I'm testifying before a House Democrat panel next week...

-----

btw, do I get college credits if I finish this thread?

[Kamiak]

Originally Posted by r carl

Yokohama*RY215

Continental*Vanco 2

Both of these are ribs, and the caveat on Tire Rack says not for near-freezing conditions. The retailers tell me that at <40 degrees, the rubber starts to become hard, minimizing traction. I realize there's no power to the wheels, but traction seems relevant for lateral stability and for stopping. What do the users say on these tires, i.e., are they ok for year-round use?

What about the Michelin LTX M/S2 as a 15" option (235/75R15), i.e., slightly larger?

[Phoenix]

We have Michelin XPS Ribs (225/75x16), which are similar tires. We towed our 19-foot Bambi in subfreezing weather (around +5 degrees F) in a blinding snow storm; roadway was new packed snow over ice. I did not notice any unusual loss of traction. However, our tow vehicle didn't have much traction, either. At least our Bambi didn't try to come around our Tundra during a panic stop on the freeway when we swerved to avoid a car that spun out and came across our bow.

I wouldn't install these on our tow vehicle in the winter, but they worked fine on our Bambi in slick conditions.

[r carl]

Originally Posted by Kamiak

Both of these are ribs, and the caveat on Tire Rack says not for near-freezing conditions. The retailers tell me that at <40 degrees, the rubber starts to become hard, minimizing traction. I realize there's no power to the wheels, but traction seems relevant for lateral stability and for stopping. What do the users say on these tires, i.e., are they ok for year-round use?

What about the Michelin LTX M/S2 as a 15" option (235/75R15), i.e., slightly larger?

I would use those tires at zero degrees if the road was dry. Remember, they didnt have all season tires before 1975, just imagine what Wally had to use back then. I wont tow on snow or ice. If you do try studded tires.

[slowmover]

btw, do I get college credits if I finish this thread?

Ours won't go on as long. Thus the recommendation of skipping all but [4] contributors on theirs. As of last night I'd gone through the blogs and the preceding threads as well as REVIVED a second time. It moves pretty fast when read with the above discretion.

.