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Tire Temperature Safety range

Wethead

New member
I have been trying to find out what is the temperature safety range of a motorcycle tire...Like an RT tire.

At what temperature do I want to set my TPM temp reader such that it buzzes the alarm before I get into that hot zone.

One ridiging across the desert I hit 56 psi on my GT and the tire was boiling, could not touch it.
I always wondered how close was I to that tire falling apart on me.

I have a TPM that registers max/min temps entries to buzz an alarm beyond/below setting, and I would like to find out where to set my max temp at
 
I found this quote. There was no source so I have no idea what kind of tires they were referring to. But it still might be a useful guideline for when to start worrying.
"Most experts consider 195 degrees Fahrenheit as the “line in the sand” when it comes to tire temperature: Beyond that point, the temperature will start impacting tire life. At 250 degrees, a tire will start to lose structural strength, could begin experiencing tread reversion and the tire will begin to lose strength."

Those limits are 90˚C and 121˚C.
 
One ridiging across the desert I hit 56 psi on my GT and the tire was boiling, could not touch it.

For every 10 degrees F increase in temp pressure increases ~1psi. So if you put 42 psi in your rear tire 'cold' (and close to 68F ambient) then temp was likely in the area of 200-210F w/ that kind of pressure increase to 56psi. It is said you will be able to touch a surface at 140F, but not for >5 seconds before you will remove your hand from the object. From testing done the surface temp of the tire will be a lot cooler than the internal temp.

It's impossible to get solid information on this topic I too have found. However, here are a few things that seem to be reasonable to consider for safety from everything read so far:

1. The older your tires are, the less they will tolerate overheating.
2. The faster you are riding, the greater the internal temp of the tire.
3. ALL sources say don't deflate the tire--let them cool down if you have concerns, slow down etc, but don't remove air. I think it's temperature you need to be concerned about much more than pressure. FWIW, for a decent road BICYCLE tire you typically run pressure at 130psi. No possible way you're going to BLOW the tire at 56psi it's just not that much pressure!
4. Ultimately, avoid riding in super hot conditions then you don't need to have concerns over this issue.
 
The greater effects on tire temperature are 1. Cold inflation pressure, 2. Load, and 3. Speed. Ambient temperature, while being a contributing factor, is down the list.
 
As others have said, the pressure of the tire is more of a concern than the heat, but "perhaps" not to a point that you should be overly concerned. If you are concerned, I would agree that you should be contacting the tire manufacturer, their International site if you can't get a satisfactory answer locally.

What folks seem to fail to recognize is that pneumatic tires have been used for over a century and that they are regularly used in the Middle East and other areas that see ongoing consistent ambient temperatures well above typical North American temps. Think about it, when was the last time, if ever, you heard of tractor-trailers being stopped from hauling their heavy loads across the desert because of concerns with their tires being able to handle the load/heat? We have had situations in North America where planes have been grounded because of the heat but that was due to the density of the air becoming too low to meet the safety requirements for take-off/landing.

One also has to recognize that there are several car and motorcycle racing series held during the summer on very hot days that require using basically street tires which do fine but do limit how much the racer can push on hot days because the tires can handle the heat as well as racing tires do, however, they are not usually at risk of failure.

I believe the most common cause of tire failure during operation in high ambient temperatures are from:
  • under-inflation (the lower your 68F correct PSI on a cold tire, the more flex which builds heat, which builds pressure)
  • over-loading (this exerts external pressure on the tire and creates more flex than the tire is designed for and again builds heat and then pressure)
The higher your tire pressure (within its design limits) the less flex and therefore the less heat.

IIRC, there was a move a few years ago to reduce the maximum pressure recommended by at least one tire manufacturer regarding pressures sure for seating the tire bead on their motorcycle tires and it went from a max of 90-PSI down to 70-PSI. The issue was not over the tire carcass but the tire bead was expanding to the point of failure. That is not to suggest that 70-PSI would be okay for operating those tires, simply for seating the bead.

Each tire and type of tire has its own pressure requirements and limits. Motorcycle tires typically run in the 36/40 PSI range F/R (+/- 2-4) while car tires are usually in the low/mid-30's and tractor-trailer tires are 100+PSI. An interesting example of how this works is if you look at the tire pressures for bicycles. A single-speed fat-tired bike (like the old "standard" bikes of the '50s and '60s) ran something like mid-20 to mid-30 while the lighter narrow-tired 10-speed bikes would run 75-110 PSI. These variations are far more a function of design, load and speed then of heat.
 
Since I ventured into this inquiry, there have been some folks who assert the position: "how many times have you ever heard of someone's tire blowing up due to heat"...and since apparently, one never hears of such event, I ought to disregard my search for viable safety temperature operating range of our motorcycle tires.

Let me be frank: you are insulting not only my intelligence, but also your own... with such absurd justification of: "tires will never blow up due to heat".

Here is an excerpt from one of the many articles I saw on line regarding tires/overheating/blowing up

The National Highway Traffic Safety Administration (NHTSA) reported an annual estimate of 414 deaths, 10,275 injuries, and 78,392 crashes due to flat tires or tire blowouts in 2003. These figures were recorded before the NHTSA established two Federal Motor Vehicle Safety Standards that require tire pressure monitoring system (TPMS) on all new light vehicles (Federal Motor Vehicle Safety Standards (FMVSS) No. 1382); and the updating of the performance requirements of all passenger car and light-truck radial tires (FMVSS No. 1393).

Why do tires blowout because of under-inflation? under-inflation not only decreases fuel economy. It can lead to separation or tire blowout due to the following effects on cars and tires:

Poor vehicle handling
Longer stopping distances
Increased stress to other tire components
Heat buildup

The TPMS was designed to help monitor air pressure of various tire types and was seen to aid in reducing fuel consumption and carbon dioxide emissions and to avoid traffic accidents. But despite the safety protocols in place, the number of accidents related to tires blowout is still alarming. The NHTSA’s data showed that an estimated 19,000 people were injured due to tire-related motor vehicle crashes in 2015, and 733 total deaths due to tire malfunctions during motor vehicle accidents in 2016.



If you don't have the data I request on this post, or know the information, I would suggest you just admit that instead of asserting that there is no danger parameters because people ride on those tires in Iran, Iraq, because you done it across the desert in the US, nor any other empirically unsubstantiated assumption void of any evidence.

Its ludicrous and somewhat naïve to assert I needn't concern myself with the issue based of the lack of blown-tire report from the Middle East...like if CBS is up with that issue. Yea! come to think about it, I never heard of a tire blown due to heat on CNN either, nor on Fox...therefore, that must have never happened. Geezus folks, I hope the rest of my RT was not built on those research premises.

To be honest with ya, I don't even want to hear what happens in them middle eastern countries let alone concern myself with their hot tires.



I do get the underinflation/temp correlation. I get it. I get that this inquiry might even be impractical. I get it. Some folks at the Harley shop yester pulled out articles of car tires withstanding over 1,000 deg F; and one guy claims having seen an article on folks who ran a bike tire on a dyno for more than a day at high speed before the tire discombobulated. I get that also. But still, my question is not being answered either. What is the temperature safety range of our motorcycle tires.

I doubt if I stop crossing that dreadful Diego to TX desert in the Summer, heat-fear is not going to stop me from riding...I still want to know the numbers...provided by empirical methods
 
On my R1150R I set the rear tire to 42 psi, the maximum cold pressure as stamped on the sidewall. I had a SmarTire TPMS which provided corrected psi as well as temperature. On "hot" days, say 90's or triple digits the internal air temp tended to be about 35 degrees F higher than the ambient temps. So at 110 I was seeing tire temp of about 145. Above that I hesitate to ride very far.
 
Let me be frank: you are insulting not only my intelligence, but also your own... with such absurd justification of: "tires will never blow up due to heat".

Not sure about tires but heat will blow up a thread, seen in numerous times.
 
Let me be frank: you are insulting not only my intelligence, but also your own...

If you don't have the data I request on this post, or know the information, I would suggest you just admit that.....QUOTE]

Geez, Wethead, no need to get pissy. We're just trying to help. Here's some more unsolicited advice which doesn't specifically answer your question: inflate your tires to the cold maximum recommended on the sidewall, don't exceed the GVWR, and if that doesn't work for you...slow down.
 
For the data cited regarding heat related blowouts, probably most were caused by low air pressure creating too much sidewall flex which creates extra heat.

I’d suggest for your high ambient temperature scenario, best thing is to monitor tire pressure for increase above the never exceed number. Easy enough to reduce pressure when that occurs.

Otherwise, I’d suggest there is little to worry about when operating within manufacturer specified parameters—again, the only parameters specified are inflation pressure and load rating.

If the tire has a puncture repair, things change.

There is no known TPMS system that provides a too-much-pressure warning.
 
For the data cited regarding heat related blowouts, probably most were caused by low air pressure creating too much sidewall flex which creates extra heat.


There is no known TPMS system that provides a too-much-pressure warning.

Am basing my opinion on watching blowouts with inadequate quality tires on HOT desert pavement at speed. My Airstream and truck are equipped with HAWK TPMS and over the years have experienced many blow outs dues to a quick rise in temps and then failure.....It seems that just a few degrees can cause failure. For us, I worried at temps in the 120F range and then blowouts at 125...……..learned a hard lesson from this and now go with 10 ply QUALITY TIRES...…………

Yes, this would relate to motorcycles as well......SPEED RATINGS given to motorcycle tires indicate how well they can withstand high heat under use...…...just my opinion...….OPINION.....
 
The Hawks Head Moto Track Cruiser 2 TPMS system has: High Pressure Level, Low Pressure Level, and High Temperature Level settings. I also have no clue what to set the high temp at? The factory setting on these are 70c = 158f.
 
If you don't have the data I request on this post, or know the information, I would suggest you just admit that instead of asserting that there is no danger parameters because people ride on those tires in Iran, Iraq, because you done it across the desert in the US, nor any other empirically unsubstantiated assumption void of any evidence.

Its ludicrous and somewhat naïve to assert I needn't concern myself with the issue based of the lack of blown-tire report from the Middle East...like if CBS is up with that issue. Yea! come to think about it, I never heard of a tire blown due to heat on CNN either, nor on Fox...therefore, that must have never happened. Geezus folks, I hope the rest of my RT was not built on those research premises.

To be honest with ya, I don't even want to hear what happens in them middle eastern countries let alone concern myself with their hot tires.

You asked this question on BMWLT as well and there a have been 48 replies. Honestly, only the tire manufacturer can answer your question to your satisfaction. Since this is of paramount importance to you I suggest you get a lawyer and seek the manufacturer's compliance in court.

https://www.bmwlt.com/forums/rt-series/183747-tire-temperatures-i-need-know.html
 
Caution! Rant!

No, No, No, No, not ever!

The OP over on the LT forum said that the tire pressure had risen to 56 psi in the heat so the pressure was lowered to 42 psi hot! No! Not ever! That was probably down to what would be a 30 or 32 psi cold pressure.

As a tire heats up and cools down the pressure changes. As temperature rises so does pressure, and as temperature drops so does pressure. That is what happens. Boyles Law of Gasses.

The pressure embossed on a tire sidewall is the "Maximum COLD Pressure" which by definition is at 20 degrees Celcius or 68 degrees F.

On a modern bike once the pressure is set at the bike manufacturer's recommended pressures (and air doesn't leak out, of course) you are good to go at virtually any temperatures you are likely to encounter. Yes - the pressure will go up as the tire heats up, and goes down as the tire cools off. But reducing a hot 56 psi tire to 42 psi and then riding on it was/is a disaster waiting to happen.

Interesting side note: We are currently riding G310GS bikes to Canada. These 350 pound dual-sport bikes take the same size tires as the bigger porky GS bikes. But the BMW recommended pressures are nowhere the same as on the porkier bikes. BMW says cold (20 degree C) pressures should be - gasp- 24 psi front and 28 psi rear. We run a bit higher pressures - 28F and 32R. On my R1150 that would be 36F and 42R.

So to repeat the rant. If your cold pressure is correct, NEVER, ever let air out of a hot tire because the pressure went up. Sometimes technology such as TPMS provides too much information if that information is misunderstood.

Rant over. Please carry on.
 
I think the OP's concerns are valid, but mostly in the domain of non-typical tires--i.e., defective tires as are described in this article:

https://www.revealnews.org/article/...lowouts-not-enough-to-prompt-goodyear-recall/

One would guess a tire destined for recall would very likely be more vulnerable to extreme heat than typical properly manufactured tires. The problem is of course you don't know if your newly released PR5GT is destined for recall. Or the next batch of my beloved Conti RA3GT. Considering the millions of miles done on motorcycle tires all over the world in uber hot conditions one gets the sense blowout failures are really rare. We do hang our arsses out in so many ways be it the deer, the antelope, the big female elk that hopped across the road in front of me just yesterday, the texting drivers, the DUI'ers, a bicyclist who does a u-turn in front of me at point blank range while I was going about 50mph, and when push comes to shove when your drive shaft explodes and locks up your rear wheel, well you get the idea. It seems this particular issue, tire blowouts, are very close or at the very bottom of the list of things that may get us one fine day!
 
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This is nothing more than a snapshot of riding conditions and tire pressures as measured today on my R1200RT LC. This is a close as I could get to a "tire" chop, allowing for a safe and level spot to pull over. Previous 30 miles of short straights linked by high speed sweepers taken at speeds between 70 and 95. Dunlop RoadSmart 3's. I realize the OP has concerns about more extreme riding conditions, but i was curious about conditions more common to my riding routine.

Data before the ride:

Garage ambient temp as measured by the bike thermometer: 80.6 F

Tire pressures measured by gauge: 38.5 F/43.5 R

TPMS readings 1/4 mile from my garage: 35 F/40 R

After a 100 mile one way breakfast run and almost home:

Ambient temp as measured by the bike thermometer: 96 F

Road surface temp as measured by infrared thermometer: 148 F

Tire temps measured in the same way: 148 F/ 147 R [measured in the tread center, the hottest section]

Tire pressures by gauge: 41.5 F/ 48.5R

TPMS readings: 36 F/42 R

Yeah, I guess I could have headed toward Phoenix and sampled in really hot conditions, but that is rarely in my real-world wheelhouse. Even allowing for ambient temps in the low 100's, not uncommon where I live, I feel confident the tire temps and pressures would remain in a safe range. Also, the oft quoted rule of thumb for determining cold inflation pressures adjusting for rise in ambient temps above 68 F [add 1 psi/10 F] seems roughly valid.
 
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