(09-24-2012, 08:41 PM)encantotom Wrote: [ -> ]hi todd,
have a look at this reference on truck tire temperatures and measuring methods.
what i wonder about is about how the pressure stem measuring devices like the pressure pro are an accurate measure of temps. the tire stem is metal, which is directly attached to the wheel. so the temperature that it measures is going to be hotter than the tire itself. so i may give pressure pro a call to see if the 210 degree temp that sets the alarm off is higher than the regular temp (150-180) to compensate for the rim making the sensor hot.
make any sense?
http://www.bridgestonetrucktires.com/us_...ance.asp#2
tom
Yes that would make sense.
Tom does your new model read actual temperatures or does it only alarm? I assume the pressure is just an alarm as well and does read out actual pressures.
http://advantagepressurepro.com/index.asp?PageTypeId=3
i talked to jeromy at pressure pro. a very nice and smart guy on this stuff. i invited him to post a response on all of this and hopefully he will.
i will try and summarize what he told me.
the tire temp alarm sounds at 90 degrees c (which is 194 degrees F). he says that it measures the air temp of the tire which is the closest correlation to actual tire temp.
that sounds right in line with the data we have. todd, i am not sure how you would actually figure out what temperature to put in another system if you were doing it yourself. one of the things is that too much flexibility will drive you nuts. it is nice to have it thought out by the pros. (in this case the pros at pressure pro)
later
tom
I have not yet installed any kind of a pressure monitoring unit for my tires. Initially I got out at every other stop and touched each tire with my hand. Any tire that felt a lot hotter than the others I checked the air pressure. This worked pretty well, but I got tired of having to wash my hands each time, so I bought an handheld infrared temp gun at Autozone and now get out and just aim at each tire. Typically on the steerer tires the temps run around 109-110 just after I stop. The drive tires run a little higher at probably 113-114.....I have noticed that the inside tires usually record higher temps than the outside tires, and
I am imagining (theory #1) this is because the are catching the heat from the outside tire, and not cooling off as fast. On the load range E, 10 ply radial trailer tires I get temps around 115, and if one is beginning to have tread separation the temps go up 20 degrees, or higher. After having the left rear read 135+ degrees a couple of times I pulled it off yesterday to get a good look at it and sure enough the tread was separating, so I made a quick trip to the local Firestone shop and had that one replaced. I have now replaced the right rear (2,000 miles ago) and the left rear. My
theory (theory #2) on why those are going bad is they get "scrubbed" more when I am turning (kind of like the tag axle tires get scrubbed) and seem to take more punishment because of that. The two front tires continue to do well, and show no signs if tread separation, and look as if they will go another 5,000 miles.
Your thoughts on my two theories would be greatly appreciated. At this point I'm not sure I will go with a pressure monitoring system. I get out of the coach every couple of hours to stretch my legs, and walk around the coach anyway, so I just take the infrared gun with me and check the tires as I walk. This process has worked well, with the exception of me not noticing the lugs coming loose on the right rear a few weeks ago....
the temps are very relative to what is being measured. 110 degrees after driving for a while seems pretty low to me. i would question if that is very accurate. but, it is dependent on ambient i would guess.
it is all about baselines and delta to that.
tom
Yep, it's the baselines that I'm looking for......remember our coach only weighs 29,000 GVW with only 4,600 lbs on each steerer tire and around 9800 on each rear corner (4900 on each dualie).....I would think the weight being carried by each tire would have a bearing on the temperatures. I'm sure your '90 and '02 are much heavier on each corner than mine...
I see higher temperatures than that. I also notice, especially during the summer that the tires on the side facing the sun are 10-15 degrees warmer than the tires on the opposite side of the coach. I have seen sun side front tire temperatures in excess of 135 degrees on the outside of the sidewall and the tread.
I decided to go with the TST 507 system for the new coach. This one has the flow through sensors which make it nice when adding air.
I previously used the Tire Safeguard on my '93 with flow through sensors but decided to try the TST.
Installed it yesterday and impressed with the ease of programming the system.