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perryg114 · 11-28-2011, 04:40 PM

I expect they were 235/75-R15 XL tires he is talking about.

Tires temps, what do they mean? I have felt of tires after highway driving in the summer and they were just about too hot to touch. So how do we know how hot is too hot? The tire industry must have some established limits? We see temperature A, B, C etc on the tire. C being a higher temp rating than A, I expect. So does that mean the tire can stand higher temps or is it constructed to not get as hot? The faster you drive the hotter the tire gets. The lower the air pressure the hotter it gets. Speed ratings are mainly based on temperature and not RPM. Any tire can go fast for short periods of time but it takes a speed rated tire to go 100+ for hours at a time.

The rubber is going to melt and start separating from the cords and belts and start to blister and then boom. Most car tires fail because the yahoo driving ran the tires with almost no air in them and they got too hot and came apart. I see folks driving around with tires that have about 10psi in them. I gave up trying to warn these folks because they act like you are nuts. These are the same yahoo's I see driving 80 MPH down the interstate on the way to work with a temporary spare on the front axel.

Perry

Xenomorph · 11-28-2011, 04:47 PM

The Michelin P235/75R15 M/S 2 I have are speed rated T. Guess I will have to slow down to accommodate.

perryg114 · 11-29-2011, 06:26 AM

Here is an interesting article I found on setting tire air pressures. It applies to race cars mainly. What I learned from it is that you want the tire temperature to be even from edge to center. If the center temps are higher than the edge temps then you have too much pressure. If you way over inflate the tire then all the heat is going into the center of the tread. So just because you have an E rated tire does not mean that you should automatically run it at 80psi when it is only at 60% of the rated load. So the knee jerk run the max pressure all the time is probably not correct. On my cars and trucks I NEVER run at max psi unless I am at severe loads. On my Ranger truck I run about 20-25 psi in the rear and 35psi in the front. If I ran 35psi in the rear I would not be able to get any traction.

Tires - Tech, Guide - Temperature Readings - Popular Hot Rodding

Perry

perryg114 · 11-29-2011, 06:33 AM

I was wrong on the temperature ratings. An A temperature rating is the highest.

Perry

Quote:

Originally Posted by perryg114

I expect they were 235/75-R15 XL tires he is talking about.

Tires temps, what do they mean? I have felt of tires after highway driving in the summer and they were just about too hot to touch. So how do we know how hot is too hot? The tire industry must have some established limits? We see temperature A, B, C etc on the tire. C being a higher temp rating than A, I expect. So does that mean the tire can stand higher temps or is it constructed to not get as hot? The faster you drive the hotter the tire gets. The lower the air pressure the hotter it gets. Speed ratings are mainly based on temperature and not RPM. Any tire can go fast for short periods of time but it takes a speed rated tire to go 100+ for hours at a time.

The rubber is going to melt and start separating from the cords and belts and start to blister and then boom. Most car tires fail because the yahoo driving ran the tires with almost no air in them and they got too hot and came apart. I see folks driving around with tires that have about 10psi in them. I gave up trying to warn these folks because they act like you are nuts. These are the same yahoo's I see driving 80 MPH down the interstate on the way to work with a temporary spare on the front axel.

Perry

AlbertF · 11-29-2011, 07:17 AM

The A, B and C temperature ratings are part of a tire quality rating system introduced in the US about 30 years ago. I'm going from memory, but this is what I remember:

C is 87 mph or 140 km/h
B is 112 mph or 180 km/h
A is 130 mph or 210 km/h or more

A and B are equivalent to the international H and S speed ratings.

Lance M · 11-29-2011, 08:00 AM

From Tire Rack dot com

UTQG
Tire Tech Information - Uniform Tire Quality Grade (UTQG) Standards

A Over 115
B Between 100 to 115
C Between 85 to 100

RTurnConn · 11-29-2011, 10:05 AM

Quote:

Originally Posted by perryg114

Here is an interesting article I found on setting tire air pressures. It applies to race cars mainly. What I learned from it is that you want the tire temperature to be even from edge to center. If the center temps are higher than the edge temps then you have too much pressure. If you way over inflate the tire then all the heat is going into the center of the tread. So just because you have an E rated tire does not mean that you should automatically run it at 80psi when it is only at 60% of the rated load. So the knee jerk run the max pressure all the time is probably not correct. On my cars and trucks I NEVER run at max psi unless I am at severe loads. On my Ranger truck I run about 20-25 psi in the rear and 35psi in the front. If I ran 35psi in the rear I would not be able to get any traction.

Tires - Tech, Guide - Temperature Readings - Popular Hot Rodding

Perry

I run my Corvette on various road courses (VIR. Rd Atlanta, etc) and the "serious" racers have their tire temps checked by a "helper" as soon as they pit in. Temps checked on outside, middle and inside of tire for the reasons you state above. My simpler technique it just to see where tires seem to be wearing......outside or middle and adjust pressure accordingly. I'm not that serious a track competitor.......just there for fun.

perryg114 · 11-29-2011, 10:43 AM

My point is that running too much pressure might contribute to tire failure by concentrating the heat in the center. Another way to balance pressure is the chalk mark test. You put a chalk mark across the tread of the tire then drive a few feet and see if the chalk mark is wearing evenly. If it is lighter in the center you have too much air. If on the edges then too little air. The temperature readings should indicate the same thing although if done on a hot tire would be more accurate than the chaulk test. The temperatures I am seeing as sample tire temps for racing tires seem to be around 200 F. So I would say to stay well below that.

Perry

Bob Thompson · 02-06-2012, 03:09 PM

There is an additional advantage to those people buying the Michelin LTX M/S2 tires. They are one of the lowest rolling resistance tires available which means improved fuel economy for the tow vehicle. Gas mileage improvements of 1.5 to 2 mpg are not uncommon.

artwester · 02-07-2012, 05:03 AM

I'm towing an '05 31' Classic with an '09 Silverado 2500 HD DuraMax/Allison. I had several very destructive flats with Goodyear Marathon Radials. This past summer I developed side wall-bubbles after only 14K miles on my last set of Marathons.

I replaced my 15" wheels with 16' wheels, and mounted Michelin 16" LT 225x75x16 tires. The clearance was reduced about 1/2", but after 14,000 miles I can find no evidence of the tire touching the trailer body. The tires still look new, the trailer tracks beautifully, and the GVW of the tires exceeds the GVW of the trailer by a large margin.

I had the changeover done in Lakewood, Colorado by Discount Tire, fair price, excellent service!

Kosm1o · 02-08-2012, 05:06 AM

Quote:

Originally Posted by Bob Thompson

There is an additional advantage to those people buying the Michelin LTX M/S2 tires. They are one of the lowest rolling resistance tires available which means improved fuel economy for the tow vehicle. Gas mileage improvements of 1.5 to 2 mpg are not uncommon.

I have the 15" Michelins and although the tire pressure is only 50 psi vs. 65, I have notice no difference in handling. If there is any difference in mileage , it is slightly better but definitely not worse. Getting 11 - 13 here in Michigan with our 28 footer and Chevy Slverado 1/2 ton .

perryg114 · 02-08-2012, 07:31 AM

The Michelins are definately good tires. There is a thread on here somewhere about a guy that put like 60,000 miles on a set and he just replaced them due to age and there were no failures. Now compare that to all the threads about my Goodyear Marathons Exploded.

Perry

Sal44 · 05-23-2012, 10:07 AM

So what's the conclusion on P vs LT michelins for a 15" wheel? Discount tire is willing to put them on my wheels but the LT doesn't seem to be available any more. Thanks

perryg114 · 05-23-2012, 12:41 PM

I really don't think there is a difference in P versus LT. Anything that has that kinda of load rating is going to be for an SUV or light truck. They don't make cars that weigh that much anymore.

Perry

Sal44 · 05-24-2012, 04:33 AM

Thanks Perry. My trailer weighs about 7000# total so about 6000# on the tires and I'm really trying not to have to make the move to 16" wheels.

perryg114 · 05-24-2012, 05:53 AM

What you want is a tire with a service rating of 108 or higher. It is commonly called and XL rated tire. The standard 15" tires are like 105 rated. I know that you can get a 108 in a BF Goodrich or a Michelin.

Tire Tech Information - How to Read Speed Rating, Load Index & Service Descriptions&

Perry

Wayward · 05-28-2012, 10:38 AM

This 235/75 15 XL tire looks like a good choice for those who do not want to go to 16" rims. I think the Michelins have been discussed well here and even at 2183lbs max load, seem to cover most Airstream GVWRs pretty well.

Here is another choice, the Firestone Destination LE 2 with a max load 2271lbs.

I have run Firestone Destination ATs on my F150 T.V. for many years - excellent tires.

Sal44 · 05-30-2012, 12:49 PM

I went with the "P" michelins and added TPMS. Now I'm selling my almost brand new GYMs. $700 for new tires and peace of mind.

howco · 06-01-2012, 09:32 AM

I bought a 1970 A/S and it had 5 Chinese bias ply, 8 ply tires on it (including a spare), I have put over 7000 miles on it and just got back from another 912 mi trip. I am towing it with a Burban with radials on it. "SO FAR" , I don't see understand all of the whining about chinese tires. Mine are working very well. I will run them down a bit and probably purchase some Michelin Radials.
I also hear about not mixing radials with bias on the A/S, mine tracks very well, no complaints.
Aren't there some decent tires coming out of China?
Just saying....

Kosm1o · 06-01-2012, 05:42 PM

I think most of the carping about tires is about "st" or "trailer" tires , whether made in China or not. That is the issue here and on many other forums where folks talk about trailer tires.
Many have switched to LT or light truck tires that dont suffer from the types of failures common to ST tires.