TPMS - Tyre Tire Pressure Monitoring System

Athdeb

Athdeb

Forum Member
Joined
Jun 11, 2012
Messages
29
Location
Townsville Queensland
Hey all,
recently had a rear tyre go flat while highway driving. Didn't notice anything wrong until the XV started shuddering violently and then I stopped right away. To my shock and horror the tyre was in two pieces, the outer side wall and the rest were completely separated. The tyre is, was a standard geolandar and replacement was a bit over $300. If it is possible to destroy a tyre without me noticing I was wondering if anybody has Tyre Tire Pressure Monitoring Systems fitted and what they are like? As we do a bit of off-road driving, water, sand, mud, dust etc how would the senders handle the conditions? They seem to be cheaper than a new tyre so I wish I had one a month ago!
Deb
 
https://youtu.be/XMa96U5lsjk - that's about all I know about them.

My wife has 45 profile tyres and its pretty hard to tell they're flat from inside the car unless you're cornering hard.

70 profile tyres are great because if a tyres flat one corner droops.

They seem like a good idea, and if they save you another tyre they've paid for themselves.
 
sjm said:
There are quite a few threads about this on subaruforester.org. Most seem to be concerned with disabling it!
Click to expand...
It's very hard to detect flat tyres on the XV fitted with the Yokohama Geolandar.
Especially if you are just cursing down the highway. TPMS is a good idea for saving tyres and safety. Try claiming a new tyre under warranty from Subaru or Yokohama because you drove it to death as you were oblivious to any vehicle handling changes!
:lol:
 
Each tyre has a pressure sensor which transmits to a receiver mounted in the vehicle. There is a single LED mounted on the dash that lights up when there is a problem. You cannot read or monitor the tyre pressures individually.

Each sensor has to be registered to the receiver (so you don't read other tyres nearby). This is a big problem if you're changing wheels (eg, if you put the spare on, the LED will be on all the time, and you won't notice if you get a flat in one of the other tyres). This is why a lot of people choose to disable it. The low pressure threshold at which the LED turns on, and the high pressure threshold at which it turns off has to be programmed using a Subaru Select Monitor. These are not available to the public. If you want to change the levels at which it switches, you'll have to pay Subaru to do it.

If you do a lot of off-road driving, you're obviously dropping your tyre pressures, so the LED will stay on. If you do get a flat off-road, you won't notice because the LED is already on. However, once you re-inflate back to highway pressures, the LED won't turn off, so you'll notice it then, but by that time, the tyre may be trashed.

And of course, each sensor has a battery which needs replacing on a regular basis - which means removing the tyre from the rim. Not something the everyday casual driver can easily do.

At first glance, TPMS does seem to be a good idea, but the lack of sensor ID selection and user-programmable thresholds makes it more of an annoyance for serious off-roading.

Note: I'm referring to the Subaru OEM system here, as used in the 2011 Forester, other systems may differ.
 
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