Temperature Of Wheels after 80 mile drive

[hobobimmer]

Howdy all from East TN's Upper Cumberland Plateau area (at least I think that is where I am).

Deb and I took 1992 Angola out for shakedown run after lots of service. Went from our little town of Huntsville, TN east to I-75, then about 20 miles north to Jellico, TN on I-75, and then did retrace of route back to bus barn.

We had just installed new hub covers, and after I parked bus, I pushed on front right steer wheel hub cover to make sure it was still tight. It was. BUT, I noticed it seemed hot.

So I touched right steer wheel. It, too, was hot. So hot I didn't want to leave hand in place. Repeated same process at each wheel. Each was hot. Although trip to and from Jellico from our I-75 exit has big hills involved, I did not use brakes much.

Is this type heat normal on our wheels (all of them) after about 80 mile trip? We have never had reason to touch our wheels before, so just don't know if they get hot like they did today. Thank you.

eric and deb faires
huntsville, TN

[MangoMike]

Hi Eric,

Don't know about the wheels, but FYI, I check the treads on the tires during rest stops after about 150 miles and during the summer they'll usually read 130 - 140 degrees.

I'll make it a point to check the wheels next time.

Mike

[mikedee]

I have shot the tires and wheels when traveling with an IR gun and get 140 on the tires at the center of the tread. I check hubs and get a little cooler maybe 125 on average. Mostly from the brakes.

[garyde]

My Coach has Oil resevoir at front Hubs and on tags. check oil levels. Other than that, they do get hot depending on road temp.

[nrhareiner]

I have Smartire installed on my coach. Since the units are mounted on the wheel, the temp reading are probably fairly close to the temp of the actual wheel. I see temps regularly in the 140-145 degree range. The temperature of the hub would be less, but does feel warm to the touch. This is normal for the running temperature on a warm day doing 65 MPH.

[Jon Wehrenberg]

Eric and Deb's hub and differential fluid levels are perfect. I would guess their high temps (a relative term) are normal. Anything that exceeds 110 to 115 is too hot to touch so without an IR thermometer there is no way to get accurate readings.

[Darl-Wilson]

This information comes from the Bridgestone Commercial Tire site:

Dear Tire Doctor,

{With air pressure and tire temp sensors installed in aluminum wheels, what kind of temperatures should be observed while driving in 90- to 100-degree temperatures?

What air temperature reading would be too high? I am using the Smart Tire system.


Dear Tom,

Thank you for the opportunity to be of assistance.

The answer to your question depends on a number of factors, and quite frankly, there is no hard and fast rule.

There are basically three types of tire temperature measurements:

1. Probes inserted into the tire
2. Contained air temperature (which your system uses)
3. Tread (surface) temperature

A probe inserted into the tire - into either the belt edge or the bead area - the hottest points of the tire - is the most accurate method; however, it can only be performed under controlled conditions.

The contained air temperature method is the next most accurate, however, it is affected by the mounting system of the sensor - if the sensor is attached to the wheel, it will pick up heat from the wheel (which is picking up heat from the brake drum); and if it is attached to the tire interior, it will pick up heat from the casing.

Tread (surface) temperature is the least accurate; since measurement is normally performed by a hand-held unit, thus hampering repeatability, plus the question of where do you measure? The ribs will be cooler than the grooves, and the center will be cooler than the shoulders, etc. So, while all this has so far done little to answer your question, we hope it has shed some light as to why we are being a bit reserved in our answer.

Now, what can I say to try to address your question?

While this is not set in stone: A very general rule of thumb is that a properly inflated/loaded tire, when up to operating temperature - one hour or more of operation - will typically run about 60 degrees F hotter than the ambient temperature. Anything above 200 degrees F could lead to tire degradation and you need to investigate for a problem.

Best regards, Tire Doctor}

Since I have installed Tire Safe Guard on my tires I am now much more aware of tire temps. I was surprised to find that operating temps from 176 to 230 degrees is acceptable, depending on the tire.

In researching more about temps and pressure I found some interesting sites, one of them devoted to retreads and loaded with lots of information. (http://www.retread.org/Inflation/) There is also several movies on the Michelin site (http://www.michelinrvtires.com/michelinrv/toolbox/videos-demos.jsp#What_Every_RV_Owner_Should_Know) which Gary De pointed out in an earlier post. This other Michelin location give even more reference material about RV tires. (http://www.michelinrvtires.com/michelinrv/toolbox/reference-material.jsp) With much of this tread about alternatives to expensive Michelin tires retreading poses some interesting possibilities. According to the Retread.Org our tires should be functional and safe for 100s of thousands of miles, (http://www.saferco.com/retread/tires_buses.pdf)depending on the condition of the casing. The big negative here is that most of our casings would be old by the time they were ready to have a retread applied. I am sure Joe C. and "Truk" will have some input on the quality of todays retreads such as Bandag. (Now owned by Bridgestone)

Personally I would prefer new Michelin rubber but with tires approaching a grand apiece it might be time to look for some alternatives. In the meantime good maintenance and proper pressure will insure that I get a long life out of my existing tires.