Hi Spec, Oracle G Rated CHINA BOMB

[jadatis]

Your given temperatures tell me you have external sensors, and they give something in between in and outside tire air temperature. Normal inside tire temp when driving 50 to 55mph at 65 degr amb temp, is 110 to 115 degrF.
So better is to calculate the temp in tire back from the pressure rising, and set alarm on pressure.

Can make a list for you to clu on your dashboard, if you give your used cold pressures.

[JRTJH]

Rubber is an insulator, so it doesn't conduct heat well. For that reason, attempting to read the OUTSIDE temperature to determine the INSIDE temperature is not a good way to assess the condition of the INSIDE of anything made primarily of rubber.

Steel and aluminum, on the other hand, are much better at transferring heat, so measuring the OUTSIDE of a wheel will give you a better assessment of the INSIDE temperature.

For that reason, "shooting temps on tires" is not a good way to tell what's going on, probably until it's "way too late to do anything about it and the tire is damaged".....

So, I'll admit that like you, I "shoot the temps" at every stop. I check the temperature of the tire, mid center at the top on each tire. Typically, the temps are withing 5 degrees F on the same side of the trailer. Usually the "sunny side" is 10-15F hotter than the "shady side"....

Where I do find greater variability in temperatures is on the wheels. I may have 10-15 degrees difference on the same spot (top/bottom/hub/outer circumference) of the hub, and that transfers to the wheel, through metal to metal contact. That increased difference in temps between wheels can be caused by bearing issues, brake drag/mis-adjustment, hard breaking, grease on the shoes on one wheel or any number of other "need to check potential problems.....

I've found that generally speaking, when I find a "hot spot on a wheel" (metal) that the rubber tire, immediately adjacent to that spot might be 1 or 2 degrees warmer than other spots on the tire, but generally, within an inch or two, the tire temp is no longer influenced by heat transfer from the wheel.

Now, as to "what's the normal temperature" ? It will vary greatly, influenced more by external heat gain more than internal heat gain. The sun will warm the "sunny side tires" significantly more than the "shady side tires". I've seen 15-20 degrees difference after a couple hours of "hot, sunny towing"... My "concern factor" is the difference between the wheel/tire pair ON THE SAME SIDE OF THE TRAILER.... I know there will be a measurable difference between sun/shade sides, but there should be little to no difference between tires/wheels on the SAME SIDE. If there's more than 5 degrees between the wheels on the SAME SIDE, I start looking for possible issues. I'll say that I don't get "alarmed" with a single measurement that's different. It will happen for many reasons. So, I measure, if there's a difference on the SAME SIDE, I make a mental note of it and if the difference remains constant over several measurements, then I start looking.

So, essentially, tires likely won't show the "smaller temperature changes" because rubber won't conduct the heat readily. Check the wheels more closely than the tires. Metal will give you a better temperature "alert" because it conducts the heat faster. You should find a rise in temperature follows all tires on the SAME SIDE but do not correlate to the other side of the trailer on sunny days. If you see a measurable difference in temperature on the SAME SIDE on repeated checks, then let that be a warning to explore further. If it's a "single shot difference" I don't worry about it, life's too short for that kind of concern.

Unless, of course, there's a 50 or 100 degree difference, then it's time to drag out the fire extinguisher and be ready for anything to happen..... I've never had that occur.

[Tireman9]

Originally Posted by JSisemoreTX

These tires are tested and speed rated to 80 mph....not that any responsible 5th wheel owner would do that, it is just a point.

I have not seen anyone yet or heard from anyone else that has ever suggested to go beyond the Cold Max PSI intentionally (which is clearly labeled as a max on the sidewall of 110).

I believe many people also drive these rigs with fresh water tank partially or Totally full AND with other basic items (another point). So are you suggesting if it was closer to my max GVWR that my cold tire inflation should have been 10, 15, or even 20 psi OVER the clearly stated max?

The reference to Speed for ST type tires needs clarification.


ST type tire load formula used by tire companies is based on an assumed 65 mph max operation speed.


The "Speed Symbol" letter comes from a 30 minute passenger tire test and should only be considered as a relative measure of heat resistance for tires from that individual tire company as every company has it's own tolerances.

[Tireman9]

Originally Posted by rustyrider

Simply question....

What is consider over heated tire temp??? 200F is considered overheated BUT unledd you are using a special needle probe thermocouple you can not measure the hot spot on a tire as it is located inside the structure about 1/4" to 3/8" deep (depending on tire)

never have heard anyone stateing what that temp is..Its generally not stated as tires of different construction can have different critical temperatures and the user has no reliable way to get the measurement.




Running max weight on my toy hauler tires and I heat gun them every time. Well you can do that but 1. you can not measure the actual hot spot as the surface rubber is always cooler that the internal structure. 2. If you want to try and measure tire temperature you have a time limit after stopping from high way speeds (1 - 2 min Max) 3. You need to be sure to measure the exact same spot both radial and circumferential EVERY TIME you make a measurement. Heat guns are OK when measuring heat conducting items like brake drums or bearings but rubber ia an insulator so you need the same spot within 1/2" every time.

I stop, and I hate tell what the temp is running.. See comment on the importance of time

Thats why I would like someone that knows to state that.

The tires are 235 85 16 E rated..
??? LT235/85R16 or ST235/85R16 You need to get the details correct


Thanks for any info..Rich

Answers in RED


Don't bother with Temp other than the default setting of your TPMS at 70C (158F) Get your loads correctly, set pressure to support at lease 115% of the heaviest loaded tire on an axle.

[jadatis]

TM9 wrote
set pressure to support at lease 115% of the heaviest loaded tire on an axle.
When I calculate this back to the % used of loadcapacity belonging to the pressure, it comes to heavyest loaded tire on the axle of 87%.
Then assuming lightest loaded tire 10% less gives 79% used of the loadcapacity.

In my made Traveltrailer tp calculator, I go for 90% average used of loadcapacity, and determined 80% of loadcapacity does not tremble your screws or rivets loose.
With addaption of the " towbarweight" this calculator can also be used for 5thwh.
For motorhomes I ( discussable) determined that 85% of loadcapacity does not give discomfort,and in part 3 of my motorhome-tp calculator, i go from 95% used as maximum and 85% as minimum.
All to give reserve for inacuracies.

So the 79% of TM9 as lightest side ( assuming 10% weightdifference) is in line with my 80% for TT and 5thw, where no people ( or animal) in it.

Edit: miscalculated. If 45/55 weightdivision then lightest 71% used of loadcapacity belonging to the determined pressure. And this would give some bouncing, to my conclusions .

My average 90% used, would theoretically , if everything is possible to determine 100% acurate ( you can forget it) , cover 80% lightest tire, and 100% heavyest tire so a 44.4/ 55.5 % load-division, wich I think is enaugh.

[flybouy]

Can always count on clarification from abroad.

[Ramrunner]

Hey new to this forum but wanted to respond to this subject. Just removed factory tires on new fifth wheel. Replaced with Hercules st 901 all steel 14 ply tires. Will keep everyone informed on the performance of these tires. Had the hi spec tires and wasn’t sure about the quality so not taking any chances.

[jadatis]

Answer to above post #47.

Then if you give all the needed data, I will calculate a highest pressure with still acceptable comfort and gripp, so your tires can last up to 10 years of use. But then also cover them for sunlight ( not when driving .

[flybouy]

Originally Posted by jadatis

Answer to above post #47.

Then if you give all the needed data, I will calculate a highest pressure with still acceptable comfort and gripp, so your tires can last up to 10 years of use. But then also cover them for sunlight ( not when driving .

Running an ST tire for 10 years is a certian recepie for disaster. Please stop telling folks this.

[jadatis]

In Europe C-tyres ( LT) last up to 10 years, also on traveltrailers.
If you trreat ST as if they are LT, they can make UPTO 10 years, wont say every tire does, but 8 years is no exeption here in Europe.

[notanlines]

Peter, (may I call you Peter?) it is utter nonsense telling people on this forum or any forum how they may run an ST tire ten years. I can't even come up with any kind of humorous anecdote to go along with this state you made. You are sorely mistaken and seriously need to retract that statement. Please, please don't expound here on how you're correct. You simply are not.

[Javi]

Originally Posted by jadatis

In Europe C-tyres ( LT) last up to 10 years, also on traveltrailers.
If you trreat ST as if they are LT, they can make UPTO 10 years, wont say every tire does, but 8 years is no exeption here in Europe.

One thing for you to remember, outside of yourself... none of the rest of us are in Europe and most of us are damn glad we're not.

[JRTJH]

Originally Posted by jadatis

In Europe C-tyres ( LT) last up to 10 years, also on traveltrailers.
If you trreat ST as if they are LT, they can make UPTO 10 years, wont say every tire does, but 8 years is no exeption here in Europe.

If you treat hamburger like steak, it still won't be steak. If you treat water like expensive wine, it still won't go well with steak or hamburger..... Treating an ST tire like an LT tire is something that just doesn't work well here. In fact, all the manufacturers of ST tires are recommending 3-5 years of life expectancy and are suggesting replacing tires at that time.

Every ST tire "owner's recommendations for tire care" suggests that ST tires will "age out before the tread shows signs of wearing out"....

Bottom line is: If you try to get 10 years out of ST tires, you might save a couple hundred bucks. If you've got $500 deductible insurance, it'll only cost you 300 that way....

ADDED: Now, just so we're clear, Michelin DOES NOT say that tires are good for 10 years. What they do say is that after 5 years your tires need to be inspected by a professional tire service and if there is no defect seen, they may continue to be used with an ANNUAL inspection. Michelin goes on to say that even with no defects noted, ALL tires must be replaced at 10 years of age regardless of condition. They also say that any tire that has been "in storage" for 6 years should not be placed in service....

So, depending on the tread wear, after 5 years, Michelin recommends an annual "wheel dismount and inspection" to confirm the tires are usable.

That's not to suggest the same regimen with ST tires. While they may be "round and black" they are NOT LT tires and Michelin does not make any ST tires in a size that fits any Keystone RV...

[jadatis]

Originally Posted by jadatis

In Europe C-tyres ( LT) last up to 10 years, also on traveltrailers.
If you trreat ST as if they are LT, they can make UPTO 10 years, wont say every tire does, but 8 years is no exeption here in Europe.

Mostly I make long story's to explain, but they are overread and miss the purpose.
Now I thougt to make a short statement to draw the attention, and it worked.

If poster #47 gives the needed data, I will calculate a pressure, and show how I come to it .
Pressure advice for him is usefull, because if you begin to low, damage to tires can be done, wich can cource tire failure mayby only after 3 years.
I want to prefent that.

[jasin1]

Originally Posted by jadatis

In Europe C-tyres ( LT) last up to 10 years, also on traveltrailers.
If you trreat ST as if they are LT, they can make UPTO 10 years, wont say every tire does, but 8 years is no exeption here in Europe.

Europe has different speed limits for rv’s (caravans).. the Netherlands lists 50 mph max for combined weight over 3.5 tons. Your roads could be a factor as well...maybe different base material / less potholes That may be a reason for your conclusions
I appreciate your participation and would like to hear about your experiences Camping in Europe BUT I don’t think it’s helpful to advise people in the United States about your theory on manipulating the air pressure for different load and tire combinations that you reached in Holland.

It would be like me advising you how to put shingles on the roof of your windmills or insisting that you watch our football instead of your “futball” (pronounced with thick European accent)