Community Forums

Butte64 · 09-06-2021, 09:16 PM

There have been posts suggesting the high temps from the DPF and exhaust system on recent year coaches is affecting DEF quality.
Im wondering if it also affects tire pressure and temp in the area. I have 85 PSI in drive and tag tires. My PS tag, which is closest to the exhaust system, quickly increases pressure and temp while driving. It soon gets to 101 degrees and the warning starts. The others rear tires eventually get up to 101. Meanwhile the temp on the tag tire goes up, eventually getting up over 135 degrees. None of the other rear tires get that hot.

What are others seeing for pressure and temp on tag tires?

Gary.Jones · 09-06-2021, 09:54 PM

Jerry

I run 85 PSI in all my tags and drive Michelins tires and have my baselines set at 90 PSI. That lets those pressures pass through as "normal".

You know that there is nothing "God-given" about where you set your baselines and you should not set the baselines at the set tire pressure.... that is too low. You set them to a logical higher place given your set tire pressures. If your tires trigger too high warnings at perfectly normal pressures, set the baselines higher. Just don't get silly about how much increase you feel is tolerable.

Gary

Tim Fox · 09-07-2021, 04:13 AM

My tags are reasonably close to each other. About the highest any of the rears have gotten is around 104, and yes the alarm goes off at 101.

ransil · 09-07-2021, 04:30 AM

My Toad tires heat up from the engine / exhaust heat, dont notice tags heating up.

brobox · 09-07-2021, 05:26 AM

Quote:

Originally Posted by Tim Fox

My tags are reasonably close to each other. About the highest any of the rears have gotten is around 104, and yes the alarm goes off at 101.

That is what I can't understand with the factory settings. I'll bet the pavement temperature is higher than 101* during the summer in half of the nation. Why are many of the TPMS setup for winter travel only when it leaves the factory?

Butte64 · 09-07-2021, 07:55 AM

Quote:

Originally Posted by Tim Fox

My tags are reasonably close to each other. About the highest any of the rears have gotten is around 104, and yes the alarm goes off at 101.

Thanks. How about the PS tag temp? I have significant difference in temp even when pressure close.

Turbojack · 09-07-2021, 09:39 AM

Have you weighed the coach and gotten individual weights? There could be a problem with too much weigh on those wheels

Butte64 · 09-07-2021, 11:06 AM

Quote:

Originally Posted by Turbojack

Have you weighed the coach and gotten individual weights? There could be a problem with too much weigh on those wheels

Thanks, that is a good point. Those tires are all Michelin 315 at well under capacity. 85 PSI is the minimum pressure recommended even though the chart shows lower pressure possible for the weight being carried. A key point is the wide variance in temperature even though similar pressure.

jwprosser · 09-07-2021, 01:05 PM

You probably are not overloading the wheels. More than likely you have more weight on one side, remember that water tank and I believe grey tank are on the passenger side. As far as the dpf /scr causing a heat problem on your tires - nope all your exhaust is is to the rear of your tires about 3 feet away. you will get more heat from the asphalt than the exhaust.

KCBless · 09-07-2021, 02:46 PM

Could also be an alignment issue with that axle. Watch the wear on the tires and make sure it looks comparable to the other tires.

Tim Fox · 09-08-2021, 04:32 AM

Jerry, my tag tires are within a few pounds of each other. Nothing like the spread you seem to have. I would hope you have a faulty sensor, otherwise you would seem to have a mechanical issue. Have you checked to see what the sensor is seeing regarding temperature difference.

Butte64 · 09-08-2021, 07:47 AM

Quote:

Originally Posted by Tim Fox

Jerry, my tag tires are within a few pounds of each other. Nothing like the spread you seem to have. I would hope you have a faulty sensor, otherwise you would seem to have a mechanical issue. Have you checked to see what the sensor is seeing regarding temperature difference.

Tim, the pressures are close. The PS tag hits 101 and alarm goes off. The DS tag is about 99 at that point. ThThe big difference is the temp. The PS tag goes to max 104 and DS tag max 102. The big variance is in temp. The PS tag gets much hotter than DS tag or drive tires. It gets up to similar temp as steer tires.
What temp do you see on your tag and drive tires?

Turbojack · 09-08-2021, 07:55 AM

Might try and verify by putting IR temp gun on all tires when you stop and compare to the sensors.

I was told that you can also go across the tread and make sure the temps are the same all the way across. If not may have an alignment or tire problem.

Butte64 · 09-08-2021, 10:42 PM

Quote:

Originally Posted by Turbojack

Might try and verify by putting IR temp gun on all tires when you stop and compare to the sensors.

I was told that you can also go across the tread and make sure the temps are the same all the way across. If not may have an alignment or tire problem.

Good point about the IR temp gun. I have been doing that and see significant difference on outside sidewall temp and what is reported by TPMS. I also see that running in same direction for a long way with sun on the tire makes for much higher sidewall temp.

I had not thought about going across the tread, thanks.