Tyre Pressure Monitors

Discussion in 'Tech/Mech General' started by 2escapees, Mar 10, 2008.

  1. 2escapees

    2escapees Deleted User

  2. TJ-RV

    TJ-RV Deleted User

    Nice idea, but it's tough to read the tyre pressures while driving along. I prefer a continuous monitor of air pressure with sensors on each wheel talking wirelessly to a monitor panel on the dash. It doesn't take much air loss for a tyre to get really hot and fail catastrophically.

    I also check tyre temperatures using an infrared thermometer every time we stop. I walk around the rig pointing it at each tyre as I go. When it's 40-45C outside, the tyres on the sunny side of the rig can get really hot. Add to this an increase in temperature due to loss of air, and you have a recipe for disaster.

    Some years ago we were driving along in the Sierra Nevada mountains when someone passed us, honking his horn and pointing furiously at the ground. I checked the mirror and saw some smoke back there, but it wasn't obvious where it was coming from. When we pulled over, one of the tyres on the towed car had burned out. We sat on the side of the road until it cooled enough for me to put the spare on.

    A few months after this event, I read about a couple who had experienced the same thing. When they pulled over, the hot tyre on the passenger side ignited dry grass at the side of the road. It quickly spread and became a full blown forest fire. The couple eventually received a bill for $1 million to pay for fighting the fire. This was 20 years ago, so $1M was a lot of money at that time.
     

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    Last edited by a moderator: Mar 11, 2008
  3. oldun

    oldun Read Only Funster

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    To me there are four problems

    1. The accuracy is very poor indeed
    2. What happens when you change the loading in the van and want to change the tyre pressures?
    3. As stated above you can only seriously monitor the pressures when the van is stationary.
    4. I do not like the idea of the tyre valve being held permanently of its seat.

    To me they are a pure but cheap gimmick.
     
    Last edited: Mar 24, 2008
  4. des

    des Read Only Funster

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    hi tom

    what a story! btw, $1M is still a lot of dosh to us poor folks across the pond. i have the same system as you, and have noticed how much tyre temperatures rise on the road. am considering extending monitors to our toad after reading your tale - have heard before that this is not an unusal event (apart from the subsequent forest fire)

    des
     
  5. TJ-RV

    TJ-RV Deleted User

    Hi Des,

    Yes, quite scary. We run into a lot of people who've had an "unexplained" blow out. I was at one tire place getting a nail hole fixed on our car. In the next bay was a motorhome and I heard the owner telling someone on a mobile phone "When the tyre went, it caused some damage under the coach, including destroying the black tank; All that poop went all over the underside of the coach and these guys are having to deal with that".

    Hopefully, folks reading along understand the need to inflate tyres to the correct pressures based on the actual 4-corner weights of the coach. Using those weights, one then consults the load/inflation tables from the tyre manufacturer.

    When we first bought our coach (new) I asked the tech at the dealership what he'd inflated the tyres to. He said "I always put 120 psi in them". This didn't sound right, but we went on our merry way. The following morning we were in snow in the Sierra Nevada mountains, which would mean the tyre pressures had dropped with temperature. I checked the tyres and was shocked to find they were at 140 psi. The rims were rated for only 125 psi.

    Next chance I got, I weighed the coach, consulted the manufacturer's inflation table for those tyres, and found the correct pressures to be 90 psi fron and 95 psi rear. So I lowered the pressures. You wouldn't believe the difference in handling of the coach. Previously, it wouldn't drive in a straight line, but now was a pleasure to drive.

    Having the correct tyre pressure, not too high and not too low, macthed to the actual weight of the coach, affects tire wear, handling and safety.
     
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