I recently noticed a squeaking/grinding noise coming from the left front wheel so I used a infrared thermometer to check the temperature of the wheel bearing as soon as I parked in my driveway. The bearing in question showed 158 degrees when the three others showed 95 degrees. After a quick tear down I discovered a very sloppy carrier bearing and promptly replaced both front bearings before I had a failure on the road. I got lucky.

Wondering what else I could use the thermometer for I decided to check out the tires. After a recent trip towing a 14k fifth wheel in 115 degree weather for 120 miles, I checked the temperature of my tires. Both the truck and trailer have 16 inch wheels with load range E tires inflated to 80 psi.
The truck tire tread measured 165 degrees with 155 degree sidewalls.
The trailer tire tread showed 155 degrees with 145 degree sidewalls.
All the tires were within 1 degree of each other when grouped by vehicle.

The maximum tire pressure is 80 psi per the tire manufacturer.
The truck tires were loaded to 82% capacity.
The trailer tires were loaded to 71% capacity.
If either tire was loaded to 100% capacity, what would the tread and sidewall temps be? In short, what is the maximum temperature the tires can take before they began to fail?

Thanks

 

All of this is really relative to ambient air temp/ road temp!! If the road surface is 110 degrees the tires are only 55 degrees warmer!! It is a good way to check if the tires are tracking right if you got a 1 tire real hot the axle could be bent or out of whack!!
What brand temp gun you got? I got a good deal at the hobby shop $22.00 like this
http://www2.towerhobbies.com/cgi-bin...?&I=LXEMG5&P=0
It is pretty good I wanted one for years!! It is hard to say failure temp. But they can
take a lot, If you are going to change a tire soon anyways run it at half pressure and see how hot it gets!!

 

You bring up a good point. Actually, the temp of the asphalt in front of my home was about 150 degrees. So the tires were only slightly warmer than the road was.

I have a Craftsman multimeter with a built in infrared thermometer. It also has the thermocouple feature, but I lost the attachment. I need to find it or get a replacement because I think the readings might be more accurate.

I have been tossing around the idea of making my own 'homemade' tire pressure sensors for my truck. If I can get 4 cheap infrared sensors and mount them on the leaf springs, pointing right at the sidewalls and then have a digital guage inside the truck.......
I know it really won't show me the pressures, but it will show when a tire is getting hot and maybe avoid a blow out.

So far I have been lucky. I have only had two tire failures in 196k miles. The first time was with the original Firestones (no trailer). The second was when I ran over something on the highway with my boat in tow.

I am pretty **** when it comes to checking my tire pressures before a trip with a trailer.

 

This is an old thread that seemingly went nowhere. I want to resurrect this issue and see if the passing of time can shed some light on this very expensive and dangerous subject. Two kids were killed today when trailer tires exploded and took the wheels off the truck. That's the first responders opinion and time may prove otherwise. But I was pulling a 10K 2 axle trailer with a 350E PSD and was having tire issue of my own. The road being littered with tire fails, I have to believe this is more than just an under inflation, under investment question.

So here are my factors:
After 200 miles at 60 mph, the trailer tire temps were 125 at the sidewall and 135 at the tread on the cool side. On the sun side, all were 10 degrees warmer.

On the van the rears were the same and the fronts 10 deg cooler.

Van was at gross; 10K but is clearly rear end heavy because of the hitch and the interior load which cannot be shifted. The trailer axles are 6k ea.

Tires are E rated all round so my rears on the van are over loaded if the rear axle is supporting more than 6K of the van's 10K gross which I suspect they are.

Ambient was 97 and surface was 13 asphalt and 120 concrete.

I lost a trailer tire, the last of 4 purchased last year from National Tire; all had belt fails.

My contention is that none of the ST trailer tire load ratings are worth the rubber they are embellished upon. They are rated for these loads in Standard Conditions aka 68 degrees ambient and only for flat even surfaces. Add typical US road conditions, cross winds, braking, and sustained speed at 65 (their speed rating) and their "life" such as it is, declines exponentially. So if the reasonably life of a no sun aged tires is say 20K miles, then under the conditions I just described, the life is probably no more than 3K or 4K at the most?

 

I later posed this question to a Bridgestone engineer that I happened to meet one day and he said that temp varies quite a bit throughout the tire casing. I think he said there are about a dozen places where temps can reach a critical stage so while measuring a certain point is useful for comparisons sake...it doesn't really indicate if a failure is imminent.

He basically recommended that I keep an eye on my tire pressures...that is the single most critical thing to check each and every time I hit the road. Then if I choose to check tire temp....try and be consistent and look for any readings that are very different from the rest. (makes sense when you think about it that way).

He said the most useful tool is a system that actually measures tire pressure while mobile. There are actually quite a few on the market now. Here is one that I saw that has a lot of neat features. I am considering getting this but the price is prohibitive since I have 12 tires to watch over.

Tire Pressure Monitoring System

 

I use a PressurePro TPS which is set to alarm at 12.5% and then again at 20% over the Base setting which I program. Price and function seem to be the same as the URL you posted.

So given that pressure rises by 1 lb per 10 deg from ST, that means on a cool morning I need to start at 81 which becomes my Base. That means the alarm will sound when the pressure passes 91.1 psi. To increase 10 psi that means temps have to increase by 100 deg or reach roughly 180 deg.

No where on the exterior of my tires have I seen more than 140 deg in 100 ambients and 150 surface temps. But the tires still failed. The previous 2 I pulled before they failed because I could feel a slight protuberance in the surface of the tread. Almost as if the tread had a crown. I have learned this is a sign that a belt has or is about to fail. I thought I felt the same thing on this weekend's failure but was not sure. Lesson is I cannot afford to doubt that and may in future put a flat surface against the tread to overcome my optimism.

I also travel with two trailer spare tires otherwise my range is limited.

BTW I have had the axle alignment checked, and the tires are always balanced. NTB had the cheek to suggest that "nobody balances trailer tires"...I had to beg them to indulge me.

Now using Carlisle but they are the same Chinese POS that everybody else sells including Goodyear.

 

I quit using ST tires long ago.
I always use 16" LT tires when possible, even if that means switching the wheel size to accommodate. My current trailer came with 15" wheels and ST tires from the factory. A condition of the sale was they needed to be changed to 16" wheels with LT tires.

Things may be different now....but last I checked, ST tires are not DOT certified.

 

You are right they are not DOT certified and AFAIK they are not checked/verified/ tested by anyone else but us suckers. Hence allowing the stuff to come out of China the same way they exported lead painted toys and defective milk products.

But I have always been told not to use LT tires on trailers as they are not suited to the load/use/alignment of a trailer. You open an avenue of hope for me because its very logical that a truck tire has to be more resilient and rating compliant than the junk sold as ST?

What am I missing here - the only thing I can understand about the so called suitability of ST tires is their supposed additional UV protection because trailers get left sunny side up for months or years at a time. But I cover my tires so thats hardly a reason to waste money on replacing trailer tires every year. Just sayin is all!

 

Not sure why LT tires would have any issues, they work fine on pickup trucks and many of us work our trucks pretty hard at times.

I've been using LT tires on my 5ers for about 10 years now. I usually replace tires when they get about 5 years old just because the rubber dries up in my climate. I never wear out the tread though. If there was any sort of alignment issue it would show in the tread wear for sure. I recommend you buy the correct tire for your needs in regards to capacity. Generally speaking, a wider tire will have a higher load index and thus greater load carrying capacity. However, a wider tire also has more rolling resistance which wastes fuel and generates more heat as well as more twisting force when making tight maneuvers on multiple axle trailers.

If I remember correctly, I think I am running LT215/85R16E tires on my RV trailer. Their load index isn't that great (only about 2700 lbs each) but still about 20% more than I need so it works out. They roll nice and easy. If you have a double axle trailer than 235 series tires might do the trick. Again, check the load index of the tires before you buy. Don't get hung up on the load range "D" or "E" rating because there is some overlap there. There are load range "D" tires that have a higher load index than many load range "E" tires so you have to choose carefully.

That being said...I would never run load range D tires on any of my heavy trailers. The range values of D, E, F etc relate to sidewall ply count. In theory, and generally speaking, the higher the load range alpha character, the more plies on the sidewall and thus the stronger the carcass. This is only a rule of thumb though and not totally accurate under all situations.

 

I decided to go with 17.5 inch Bridgestone G rated on the truck which is at 10K and 16 inch LT-E rated Michelin Ribs on the trailer which is also at 10K. The combined and individual max weights are within 10% of MAX so I do not have much in the way of a safety margin. But it has to be better then where I was.

I know some people work their trucks hard bu actually most do not. Even with 2.5K on the 5th the truck itself is often well under gross. But 65 mph at 100 deg on a typical interstate at gross weight probably means the tires do not last more than 10K miles. Obviously I can increase that for the periods that I am not towing or on the interstate but thats less than 20% of my use.

But to the point made in some of the posts - my Bridgestones are rated at 3750 lbs (G) but at 100 psi. All the other G rated tires only get the same load rating at 110 psi. Do I have more margin...who knows! Its a Vegas game it seems to me.

 

I have to wonder if the TPM system makers talking about warning of over inflated, or over temp for properly inflated tires, aren't just playing on people's fears. Preying on people's fears is an all too common marketing ploy.

I find it difficult to believe that tire manufactures don't test their tires in the most extreme conditions. i.e., cold inflated for maximum load then run in hottest conditions.
I could be wrong and the tire manufacturers figure not many people will use them like that so don't care, but I really doubt it.

 

I agree that in any area where either liability or commercial competitive pressures demand, the manufacturers have improved the breed to the point that if you stick to their limits, all other things being within spec, the tires will operate safely and offer reasonable value. the problems arise when you go off the reservation load, alignment or spec wise. In those instances the margins vary all over the map with ST tires being so far down the list that you probably will not get value from them if you operate them at the designed max load in any temperature over 80F - IMO. Things get better in truck tires and better still as you move into commercial spec "rib" tires and "over the road" products. But if you overload, misalign or run those tires off road your odds of safety and value disappear and there is no way you can predict the rate.