High Inner Drive Tire Temp

[Mocephus]

Hi friends, we have a 2005 Monaco Signature.  About 30 min away from our destination to Hilton Head yesterday, I started getting high temp alerts on the two inner drive tires. I suspect the brakes are bound. I’m not super familiar with the brake system but I do have the tools on board to do some repairs. What should I look for when I get under the coach (safely)?

Thanks in advance for your help!

[tmw188]

Curious what are you calling high temps?

[Mocephus]

14 minutes ago, tmw188 said:

Curious what are you calling high temps?

 

5 minutes ago, Mocephus said:

I believe the temp got to 158 when the alarm was sounding. 

 

Edited June 9, 2023 by Mocephus

[Ivan K]

If it really is the case, you are very limited to what you can check and see with wheels on and park brake applied. Other than just trying to feel the disk from behind the wheels. With park brake off, and someone stepping on the brake you would see the canister rods applying and releasing but still not know if the pads actually back off. It is normal for the inners to get a little warmer on a crowned road so it depends. Just be very careful getting under it and blocking the wheels if you release park brake for inspection. I don't think 131F is a big concern, slow down and see.

Edited June 9, 2023 by Ivan K
Spelling

[Mocephus]

44 minutes ago, Ivan K said:

If it really is the case, you are very limited to what you can check and see with wheels on and park brake applied. Other than just trying to feel the disk from behind the wheels. With park brake off, and someone stepping on the brake you would see the canister rods applying and releasing but still not know if the pads actually back off. It is normal for the inners to get a little warmer on a crowned road so it depends. Just be very careful getting under it and blocking the wheels if you release park brake for inspection. I don't think 131F is a big concern, slow down and see.

Thanks Ivan, I had to correct the temp. It was actually 158 when the alarm sounded. 

[Frank McElroy]

2 hours ago, Mocephus said:

Hi friends, we have a 2005 Monaco Signature.  About 30 min away from our destination to Hilton Head yesterday, I started getting high temp alerts on the two inner drive tires. I suspect the brakes are bound. I’m not super familiar with the brake system but I do have the tools on board to do some repairs. What should I look for when I get under the coach (safely)?

Thanks in advance for your help!

What were the temps of the outer drive tires?  Also were you using your service brakes at the time vs using the Jake brake?

[Ivylog]

What psi are you running in the drive tires. Since both sounded off, doubt it’s a brake issue. It’s normal for the inner to run hotter but 158 is higher than any temp I’ve seen.

[Mocephus]

1 hour ago, Frank McElroy said:

What were the temps of the outer drive tires?  Also were you using your service brakes at the time vs using the Jake brake?

Hi Frank, I think the outer drive tires were in the 130’s but I can’t remember for sure as I was having to watch traffic closely. The TST system alarms at 158 so that was the temp of the inner tires. We were in stop and go traffic on flat grade. Jake was not on. 

57 minutes ago, Ivylog said:

What psi are you running in the drive tires. Since both sounded off, doubt it’s a brake issue. It’s normal for the inner to run hotter but 158 is higher than any temp I’ve seen.

 

57 minutes ago, Ivylog said:

What psi are you running in the drive tires. Since both sounded off, doubt it’s a brake issue. It’s normal for the inner to run hotter but 158 is higher than any temp I’ve seen.

100 psi

[vito.a]

Turn the Jake brake on and use it at least on low.  

[Mocephus]

49 minutes ago, vito.a said:

Turn the Jake brake on and use it at least on low.  

Thanks Vito, that’s a good idea.

[TomV48]

9 hours ago, Mocephus said:

Thanks Ivan, I had to correct the temp. It was actually 158 when the alarm sounded. 

Thank you IVAN but now for us mere mortals can you explain what solved the problem.  (IN OTHER WORDS WHAT CAUSED THE PROBLEM)

I would be alarmed if my tire temp hit 158 which I think is the default setting in our TST's.   I hit temp alarms with two wheels on our TOAD one day just 5 miles from home and found that I had positioned my Removable Brake Controller BADLY and caused the brakes to drag.  Easy Fix and according to my mechanic, no real damage to the brakes, but without the TRUSTY TST we could have had a TOAD with blazing tires and a real problem.

Edited June 10, 2023 by TomV48
omission

[Jdw12345]

I carry one of these on the coach at all times, pretty handy item to have along!

 For checking temps on everything! Tires, drive axle, brakes, engine, …………

https://www.amazon.com/Fluke-59-Laser-Infrared-Thermometer/dp/B00G1V3FG8/ref=sr_1_4?crid=2ED0RDFEFC6YQ&keywords=fluke+laser+temp+gun+thermometer&qid=1686356052&sprefix=Fluke+laser+temp+gun%2Caps%2C201&sr=8-4&ufe=app_do%3Aamzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc

[TomV48]

4 minutes ago, Jdw12345 said:

I carry one of these on the coach at all times, pretty handy item to have along!

 For checking temps on everything! Tires, drive axle, brakes, engine, …………

https://www.amazon.com/Fluke-59-Laser-Infrared-Thermometer/dp/B00G1V3FG8/ref=sr_1_4?crid=2ED0RDFEFC6YQ&keywords=fluke+laser+temp+gun+thermometer&qid=1686356052&sprefix=Fluke+laser+temp+gun%2Caps%2C201&sr=8-4&ufe=app_do%3Aamzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc

ME TOO BUT Harbor Freight at about $20 as FLUKE would be over my budget

[Frank McElroy]

19 minutes ago, Jdw12345 said:

I carry one of these on the coach at all times, pretty handy item to have along!

 For checking temps on everything! Tires, drive axle, brakes, engine, …………

https://www.amazon.com/Fluke-59-Laser-Infrared-Thermometer/dp/B00G1V3FG8/ref=sr_1_4?crid=2ED0RDFEFC6YQ&keywords=fluke+laser+temp+gun+thermometer&qid=1686356052&sprefix=Fluke+laser+temp+gun%2Caps%2C201&sr=8-4&ufe=app_do%3Aamzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc

Yes, I carry a similar unit to check both tire and axle hub temps at every rest stop and final destination stop.  It's part of my rest stop and post trip inspection.

[Mocephus]

24 minutes ago, Jdw12345 said:

I carry one of these on the coach at all times, pretty handy item to have along!

 For checking temps on everything! Tires, drive axle, brakes, engine, …………

https://www.amazon.com/Fluke-59-Laser-Infrared-Thermometer/dp/B00G1V3FG8/ref=sr_1_4?crid=2ED0RDFEFC6YQ&keywords=fluke+laser+temp+gun+thermometer&qid=1686356052&sprefix=Fluke+laser+temp+gun%2Caps%2C201&sr=8-4&ufe=app_do%3Aamzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc

Great idea! Thank you

[Frank McElroy]

Here is an example of my typical tire pressures.  The inner drive only runs about 1 PSI maybe 2 PSI higher than the outer drive.  I use the Jake brake almost exclusively.

[96 EVO]

I began typing my crazy story with toad brakes overheating, (hot enough everything had to be replaced down to the spindles) but, it's not inline with the original post.

One day I'll post it.

Edited June 10, 2023 by 96 EVO

[Mocephus]

1 hour ago, Frank McElroy said:

Here is an example of my typical tire pressures.  The inner drive only runs about 1 PSI maybe 2 PSI higher than the outer drive.  I use the Jake brake almost exclusively.

I have never really considered keeping the Jake on all the time and the benefits of that. Thanks for the idea Frank. Impressive systems monitor you’ve created there!

1 hour ago, 96 EVO said:

I began typing my crazy story with toad brakes overheating, (hot enough everything had to be replaced down to the spindles) but, it's not inline with the original post.

One day I'll post it.

I’d love to hear that story!

[Frank McElroy]

9 hours ago, Mocephus said:

I have never really considered keeping the Jake on all the time and the benefits of that. Thanks for the idea Frank. Impressive systems monitor you’ve created there!

I’d love to hear that story!

I may have confused you.  I don't leave the Jake brake switch in all the time.  I only turn it on when I need braking.  If you leave it on all the time, on my coach, cruise control won't work and every time I took my foot off the throttle that Jake would come on.

[Tom Cherry]

Been away on an urgent family matter.  Couple of comments on this....based on my own experience as well as others.... NOTE....a bit long, but the understanding of "Tire Temperatures" is important and any EXTERNAL TPMS can NOT accurately measure that. It is measuring the OUTSIDE temperature....and that is a STRETCH when you are concerned about the REAL temperature....which COULD result in a failure....  SO, if you are interested.....here goes....

The "tire temperature" is a somewhat relative term.  There is no TPMS, other than those with INTERNAL sensors that are mounted on bands like the original SmarTire system that accurately displays the TRUE (interior) tire temperature.  There was a LOT of discussion many years ago about this and I did a little (OK a lot) of reading and experimenting.  The TST or the PressurePro or any other type of exterior mounted TPMS is only displaying the "relative" ambient temperature of the tire and not really the interior temperature.  YES....that is or could be a good "rule of thumb", but the real concern is what the temperature of the tire "IS" inside the tire.  

I developed a spread sheet that one person "checked" and it gives you the ability to calculated the REAL internal tire temperature of the tire.  It sounds complex but it is really a ratio or comparison of the old "Gas Laws" that many of us studied in college or maybe high school.  I looked at it this morning and if there is some interest, I'll forward a copy, via PM, to any member that really wants to KNOW the true internal tire temperature.  

NOW....having said all that and such, there is a few things that folks OUGHT to know and take into consideration.  The FRONT tires are the real concern, generally speaking, from a RUD (Random Unscheduled Disassembly)....That term is credited to SpaceX as they used it to explain "why" a rocket blew up a few hundred or maybe a few thousand feet up from the launch pad.  That was a $2 Billion (memory and probably wrong) event....and they "calmly" offered the RUD term and moved on.  

NOW, in the rear, there are some different dynamics.  If you do a LOT of data gathering or watching, you have probably noted that the two interior tires run at a higher pressure than the two outers.  SIMPLE....the Differential (Hogshead for us old gear heads) heat up.  If you are pulling a grade or descending (using your Exhaust/Jake brake), watch the temperatures of the engine and transmission.  You will see a higher rise in the transmission as that is under more strain. Conversely, so is the differential.

The OTHER factor is air flow (and ambient of course....but lets stick with the Delta T or the difference in temperatures) and the environment.  The inner rears will be around 3 - 4 PSI MORE after a while than the outers. Many of us set the inners lower and when you drive, you will see the pressures equalize in about 30 minutes or so.

The heat from the differential is radiated to the inner tires and the gap or spacing between the inner and the outer does not promote good cool down. BUT, on the outer, you have the cooling effect of turning as well as NOT having that big "space heater" heating up the world under the MH.  This is easily proven using both data from systems with interior sensors as well as watching the tire pressure.  

My take on this....one needs to watch the TIRE PRESSURE.  That is the ONLY TRUE indicator of an issue.  YES, the temperature "numbers" on some sensors may give an indicator....but they are really monitoring the air on the outside of the tire....and NOT the inside.  ONE NOTE HERE....again from a lot of discussion with the folks at PressurePro. The original PressurePro sensors had some "Temperature Data".  BUT, it was only collected, based on the electronics, and put into "BUCKETS".  That means that the perceived accuracy of such had to be factored with some knowledge. I may get the values or the bucket ranges wrong, but on the PressurePro, you got something like 40, 70, 90, etc. ranges....and that was the intended use....as a "hey....here I am".  I suspect that as different folks entered the TPMS arena (and many also exited quickly as their electronics were not robust...as well as the fluctuations in the demand), PressurePro refined the data.  Smaller buckets....so you seemingly a more accurate system.  YES, the sensors were better and the data was better...but in reality, the new monitors and the new sensors displayed the same data....only a bit more precisely.  

OK.....this is getting deep.  Bottom Line....  Your inner tires are going to get HOTTER.  BUT, as long as you really focus on the TIRE PRESSURE...you, I think, are better off. IF you have a "sticking" rear drum, then it will get hotter than....  quickly.  If I am correct in what a wise person taught me, the rear brakes actually come on FIRST....and then the treadle valve or such modulates or increased foot pressure will then start to engage the front disc brakes.  Heat from the brakes is dissipated into the wheel and tire.  Keep driving and keep your foot OFF the brakes....like on an interstate....and the tires will go back to their normal state.

There are scads, if one is interested, articles about tire temperatures and pressures and the stuff that automotive technology schools do work on.  There is a term that many, Bridgestone for example uses.... it....I think...."Thermal Equilibrium".  Here is a C&P from the SmarTire RV owner's manual. If one is REALLY interested in learning and understanding such (and this after 50 odd years finally made sense and what my professors were telling me in college...I was a bit dense....LOL).  THEN Read pages 10 & 11 from the SmarTire RV owner's manual that is attached.  There is also a section in the front that discusses the "Temperature and Tire Pressures" or how you need to compensate and adjust such.  Posting it would really make it a bit longer....but read this... 

THERMAL EQUILIBRIUM
As a vehicle moves, its tires naturally heat up due to friction from the road and the flexing of its side-walls. Weight, vehicle speed and the inflation pressure a tire starts at all have an impact on how much and how quickly heat is generated. As the tire generates heat, its pressure increases causing a reduction in side-wall flexing. Less side-wall flexing and road resistance combined with air rushing past the tire as the vehicle moves effectively counteract the conditions that cause the tire to heat up. As a result, the temperature increase tapers until the tire reaches a point of balance called Thermal Equilibrium. Tire “Thermal Equilibrium” is the point where the heat being generated is equal to the heat being dissipated. Tires are designed with the principles of temperature and pressure in mind in order for them to achieve Thermal Equilibrium. Once a properly inflated tire reaches Thermal Equilibrium, it will operate at its peak; providing the best performance, handling, tire life and fuel economy.

Bottom line....your inner tires are going to be hotter.  If the tires (inners or outers or all) are all SET to the SAME pressure....and ONE tire has a higher pressure than the other (inners will be higher...so look at the differences between EACH inner)....then ODDS ARE...there is a brake issue or bearing....that applies to all tires....but it SHOULD be addressed. BUT, running down the highway and watching the tire pressure and knowing what to expect is the most, to me, common sense thing.

One OTHER POINT....again from my "journey down this path"....  When the temperatures go UP and your might not have the correct Cold Inflation Pressure, you will (YES...BEEN THERE), get some false alerts on "over pressure" or readings on ANY system.  When it gets hot....the TP is going up. I had to let some air out of my rears on a trip where it was 30 deg hotter and my sensors were not "set" or installed to the right CIP.  PressurePro on the original systems were set for a pressure.  I did my calculations and experiments and realized that their "points" or the default alarm points were close.

FINAL WORD (I promise). The worry point on a tire is the INTERNAL TEMPERATURE of around 180 deg F. NOW....if you ask (and I did) Michelin or Goodyear or Bridgestone or read their manual, that varies a little.  You run the risk (memory....) of starting to be CLOSE to some issues when the internal tire temperature exceeds 180 degF.  SmarTire (read the first few pages) sets or has their alarms at 195 DegF....which is pretty high. MOST folks, that understand Pressure and Tire Temp would, as I do, get worried above 180 DegF.  THAT is why I developed my spreadsheet which requires, if you have a TPMS (any brand) that you record three simple things.  The morning Pressures as well as the "Ambient" out side temperature.  THEN....drive a while...at least an hour.  Record the tire pressures.  Then put those values into the blanks on my spreadsheet and you will be within a few degrees of what your INNER TIRE pressure is....after the tires get hot.  NOW, the caveat....you need to record the pressures while driving and NOT going up or down a grade nor really "laying on the brakes".

OK...class dismissed.....need some coffee....

RV_Owners_Manual.pdf

[Mocephus]

1 hour ago, Frank McElroy said:

I may have confused you.  I don't leave the Jake brake switch in all the time.  I only turn it on when I need braking.  If you leave it on all the time, on my coach, cruise control won't work and every time I took my foot off the throttle that Jake would come on.

Oh ok Frank, thank you for the clarification. 

[Paul J A]

13 hours ago, Mocephus said:

Great idea! Thank you

Great devise. You will love it. You will see different temp's on the sunny and shade side of the coach, as you travel as well. 

[Mocephus]

1 hour ago, Tom Cherry said:

Been away on an urgent family matter.  Couple of comments on this....based on my own experience as well as others.... NOTE....a bit long, but the understanding of "Tire Temperatures" is important and any EXTERNAL TPMS can NOT accurately measure that. It is measuring the OUTSIDE temperature....and that is a STRETCH when you are concerned about the REAL temperature....which COULD result in a failure....  SO, if you are interested.....here goes....

The "tire temperature" is a somewhat relative term.  There is no TPMS, other than those with INTERNAL sensors that are mounted on bands like the original SmarTire system that accurately displays the TRUE (interior) tire temperature.  There was a LOT of discussion many years ago about this and I did a little (OK a lot) of reading and experimenting.  The TST or the PressurePro or any other type of exterior mounted TPMS is only displaying the "relative" ambient temperature of the tire and not really the interior temperature.  YES....that is or could be a good "rule of thumb", but the real concern is what the temperature of the tire "IS" inside the tire.  

I developed a spread sheet that one person "checked" and it gives you the ability to calculated the REAL internal tire temperature of the tire.  It sounds complex but it is really a ratio or comparison of the old "Gas Laws" that many of us studied in college or maybe high school.  I looked at it this morning and if there is some interest, I'll forward a copy, via PM, to any member that really wants to KNOW the true internal tire temperature.  

NOW....having said all that and such, there is a few things that folks OUGHT to know and take into consideration.  The FRONT tires are the real concern, generally speaking, from a RUD (Random Unscheduled Disassembly)....That term is credited to SpaceX as they used it to explain "why" a rocket blew up a few hundred or maybe a few thousand feet up from the launch pad.  That was a $2 Billion (memory and probably wrong) event....and they "calmly" offered the RUD term and moved on.  

NOW, in the rear, there are some different dynamics.  If you do a LOT of data gathering or watching, you have probably noted that the two interior tires run at a higher pressure than the two outers.  SIMPLE....the Differential (Hogshead for us old gear heads) heat up.  If you are pulling a grade or descending (using your Exhaust/Jake brake), watch the temperatures of the engine and transmission.  You will see a higher rise in the transmission as that is under more strain. Conversely, so is the differential.

The OTHER factor is air flow (and ambient of course....but lets stick with the Delta T or the difference in temperatures) and the environment.  The inner rears will be around 3 - 4 PSI MORE after a while than the outers. Many of us set the inners lower and when you drive, you will see the pressures equalize in about 30 minutes or so.

The heat from the differential is radiated to the inner tires and the gap or spacing between the inner and the outer does not promote good cool down. BUT, on the outer, you have the cooling effect of turning as well as NOT having that big "space heater" heating up the world under the MH.  This is easily proven using both data from systems with interior sensors as well as watching the tire pressure.  

My take on this....one needs to watch the TIRE PRESSURE.  That is the ONLY TRUE indicator of an issue.  YES, the temperature "numbers" on some sensors may give an indicator....but they are really monitoring the air on the outside of the tire....and NOT the inside.  ONE NOTE HERE....again from a lot of discussion with the folks at PressurePro. The original PressurePro sensors had some "Temperature Data".  BUT, it was only collected, based on the electronics, and put into "BUCKETS".  That means that the perceived accuracy of such had to be factored with some knowledge. I may get the values or the bucket ranges wrong, but on the PressurePro, you got something like 40, 70, 90, etc. ranges....and that was the intended use....as a "hey....here I am".  I suspect that as different folks entered the TPMS arena (and many also exited quickly as their electronics were not robust...as well as the fluctuations in the demand), PressurePro refined the data.  Smaller buckets....so you seemingly a more accurate system.  YES, the sensors were better and the data was better...but in reality, the new monitors and the new sensors displayed the same data....only a bit more precisely.  

OK.....this is getting deep.  Bottom Line....  Your inner tires are going to get HOTTER.  BUT, as long as you really focus on the TIRE PRESSURE...you, I think, are better off. IF you have a "sticking" rear drum, then it will get hotter than....  quickly.  If I am correct in what a wise person taught me, the rear brakes actually come on FIRST....and then the treadle valve or such modulates or increased foot pressure will then start to engage the front disc brakes.  Heat from the brakes is dissipated into the wheel and tire.  Keep driving and keep your foot OFF the brakes....like on an interstate....and the tires will go back to their normal state.

There are scads, if one is interested, articles about tire temperatures and pressures and the stuff that automotive technology schools do work on.  There is a term that many, Bridgestone for example uses.... it....I think...."Thermal Equilibrium".  Here is a C&P from the SmarTire RV owner's manual. If one is REALLY interested in learning and understanding such (and this after 50 odd years finally made sense and what my professors were telling me in college...I was a bit dense....LOL).  THEN Read pages 10 & 11 from the SmarTire RV owner's manual that is attached.  There is also a section in the front that discusses the "Temperature and Tire Pressures" or how you need to compensate and adjust such.  Posting it would really make it a bit longer....but read this... 

THERMAL EQUILIBRIUM
As a vehicle moves, its tires naturally heat up due to friction from the road and the flexing of its side-walls. Weight, vehicle speed and the inflation pressure a tire starts at all have an impact on how much and how quickly heat is generated. As the tire generates heat, its pressure increases causing a reduction in side-wall flexing. Less side-wall flexing and road resistance combined with air rushing past the tire as the vehicle moves effectively counteract the conditions that cause the tire to heat up. As a result, the temperature increase tapers until the tire reaches a point of balance called Thermal Equilibrium. Tire “Thermal Equilibrium” is the point where the heat being generated is equal to the heat being dissipated. Tires are designed with the principles of temperature and pressure in mind in order for them to achieve Thermal Equilibrium. Once a properly inflated tire reaches Thermal Equilibrium, it will operate at its peak; providing the best performance, handling, tire life and fuel economy.

Bottom line....your inner tires are going to be hotter.  If the tires (inners or outers or all) are all SET to the SAME pressure....and ONE tire has a higher pressure than the other (inners will be higher...so look at the differences between EACH inner)....then ODDS ARE...there is a brake issue or bearing....that applies to all tires....but it SHOULD be addressed. BUT, running down the highway and watching the tire pressure and knowing what to expect is the most, to me, common sense thing.

One OTHER POINT....again from my "journey down this path"....  When the temperatures go UP and your might not have the correct Cold Inflation Pressure, you will (YES...BEEN THERE), get some false alerts on "over pressure" or readings on ANY system.  When it gets hot....the TP is going up. I had to let some air out of my rears on a trip where it was 30 deg hotter and my sensors were not "set" or installed to the right CIP.  PressurePro on the original systems were set for a pressure.  I did my calculations and experiments and realized that their "points" or the default alarm points were close.

FINAL WORD (I promise). The worry point on a tire is the INTERNAL TEMPERATURE of around 180 deg F. NOW....if you ask (and I did) Michelin or Goodyear or Bridgestone or read their manual, that varies a little.  You run the risk (memory....) of starting to be CLOSE to some issues when the internal tire temperature exceeds 180 degF.  SmarTire (read the first few pages) sets or has their alarms at 195 DegF....which is pretty high. MOST folks, that understand Pressure and Tire Temp would, as I do, get worried above 180 DegF.  THAT is why I developed my spreadsheet which requires, if you have a TPMS (any brand) that you record three simple things.  The morning Pressures as well as the "Ambient" out side temperature.  THEN....drive a while...at least an hour.  Record the tire pressures.  Then put those values into the blanks on my spreadsheet and you will be within a few degrees of what your INNER TIRE pressure is....after the tires get hot.  NOW, the caveat....you need to record the pressures while driving and NOT going up or down a grade nor really "laying on the brakes".

OK...class dismissed.....need some coffee....

RV_Owners_Manual.pdf 1.28 MB · 1 download

Tom, thanks for the great explanation of what's going on with tire temps and pressure! That made for some very excellent and insightful reading!

I have the TST TPMS and the factory default setting for the temp alarm on it is 158 F. I've had the system on the tires from the day we purchased the rig (3 years ago) and have never had a high temp alarm before and have driven tens of thousands of miles with ambient temps exceeding 100 F, and pulling and stopping while towing a Chevy Suburban, on all types of grade. So, after being on the road for 5 hrs before the high temp alarm first sounded on the PS inner drive tire, on pretty much flat level ground, with ambient temperature around 80 F, and then about 10 minutes later alarming on the DS inner drive tire, it caused me to wonder what had changed to cause the temps to get high enough to trigger the alarms.

My first thoughts were either the brakes were dragging or maybe the bearings had gone bad (I'll be checking for leaks later). I'm trying to remember but I think the tire pressure on those two tires was around 135 PSI at the time the alarms sounded but I may be way off on that. I was in heavy stop and go traffic at the time and could only briefly glance at the monitor as I was driving. I run the drive tires at a cold pressure of 100 PSI.

So, to me....something unusual happened to cause the high temp alarms to activate. My first thoughts went to the brakes dragging and then to possible bearing failure. Any other causes that I could be missing or anything that you know of that I could look for in trying to diagnose the cause?

I'll have my co-pilot take a photo of the display if it happens when we get back on the road later this week so I'll have better data.

 

 

 

16 minutes ago, Paul A. said:

Great devise. You will love it. You will see different temp's on the sunny and shade side of the coach, as you travel as well. 

Hi Paul! Yes, I've been using it for 3 years and I like it a lot!

[Paul J A]

35 minutes ago, Mocephus said:

Tom, thanks for the great explanation of what's going on with tire temps and pressure! That made for some very excellent and insightful reading!

I have the TST TPMS and the factory default setting for the temp alarm on it is 158 F. I've had the system on the tires from the day we purchased the rig (3 years ago) and have never had a high temp alarm before and have driven tens of thousands of miles with ambient temps exceeding 100 F, and pulling and stopping while towing a Chevy Suburban, on all types of grade. So, after being on the road for 5 hrs before the high temp alarm first sounded on the PS inner drive tire, on pretty much flat level ground, with ambient temperature around 80 F, and then about 10 minutes later alarming on the DS inner drive tire, it caused me to wonder what had changed to cause the temps to get high enough to trigger the alarms.

My first thoughts were either the brakes were dragging or maybe the bearings had gone bad (I'll be checking for leaks later). I'm trying to remember but I think the tire pressure on those two tires was around 135 PSI at the time the alarms sounded but I may be way off on that. I was in heavy stop and go traffic at the time and could only briefly glance at the monitor as I was driving. I run the drive tires at a cold pressure of 100 PSI.

So, to me....something unusual happened to cause the high temp alarms to activate. My first thoughts went to the brakes dragging and then to possible bearing failure. Any other causes that I could be missing or anything that you know of that I could look for in trying to diagnose the cause?

I'll have my co-pilot take a photo of the display if it happens when we get back on the road later this week so I'll have better data.

 

 

 

Hi Paul! Yes, I've been using it for 3 years and I like it a lot!

👌🤝

[Frank McElroy]

I would check the tag axle air pressure in travel mode.  Also, verify on a set of weight scales that you have set the tag axle air pressure properly.  Also, while on the scales, the coach must remain running and in travel mode - otherwise the weight reading will not be correct. 

A failed tag axle air pressure regulator or valve in the leveling system could cause the tag axle not to carry the proper amount of weight and transfer it all to the drive axle.  Keep in mind that this could be an intermittent issue.

If for some reason the tag is not at proper air pressure or you have it set to automatically lift at low speed this would put all the weight on the drive axle.  That would surely increase drive tire pressures and temps.