Upper and lower thresholds for TST TPMS? - Montana Owners Club

KathyandDave · 10-21-2012, 04:27 PM

We bought the TST 510 system. I'm supposed to enter upper and lower values. I do know the target values for each axle, but how much +/- should I allow?

**DQDick** · 10-21-2012, 04:31 PM

In my TST manual it says 20% over and 10% under.

RJI47 · 10-21-2012, 04:48 PM

It spells it out pretty clearly in the video, but it also says you can set it to wherever you want.

Exnavydiver · 10-21-2012, 05:13 PM

But what is a percent in metric??

KathyandDave · 10-22-2012, 03:47 AM

Hahaha! I'm an engineer, so of course, I never watched the video. I DID read the little manual that came with the unit, but I didn't spot the required info. So, thanks for the excellent help. As always, the MOC is my best source.
We're off to Denver on Goodyear G614's and Michelin LTX's, with recently serviced brakes, so I feel good!
Dave

KathyandDave · 10-22-2012, 04:04 AM

I spoke too soon. After installing theTST yesterday, the passenger steering tire is flat as a pancake this morning....

**Rondo** · 10-22-2012, 04:11 AM

Dave-- You're suppose to fill the tires back up when you install the TST's!

It's just flat on the bottom!

Exnavydiver · 10-22-2012, 04:23 AM

Be sure to use metric air!!

RonD · 10-22-2012, 04:28 AM

I tried setting ours about 10 pounds under, and the same over, that didn't work, I now use 20 pounds over, and 20 pounds under, we were in 80 degree weather, all was fine, the next day we were in 37 degree weather, the pressure lowered, and the alarm went off, so the 20 pounds works better in our case, I watch the pressure when driving anyway

KathyandDave · 10-22-2012, 01:36 PM

Now I know why you have to have steel valve stems. The rubber ones are not secured against rotating as you tighten the sensor tool, even just hand tight. So, it seemed tight, but really was leaking, so the tire was flat. Using vice grips to hold the stem, tightening the sensor tool and then checking with metric soapy water did the trick. I wish I had thought of getting the steel stems when I bought the michelins. It would have been a no- brainer at the time. Specially since the michelins are naturally metric.

kab449 · 10-22-2012, 03:40 PM

My trailer tires take 100 lbs. I set low at 90 and high at 125. In 90° temps my tires routinely get close to 120 lbs and 135°. You will find out what is normal range for your tires after you install your system. I still like the internal sensors better. Easier to fill, no theft or damage, and they have steel stems.

bighornram · 10-23-2012, 08:11 AM

Quote:

quote:Originally posted by KathyandDave

Now I know why you have to have steel valve stems. The rubber ones are not secured against rotating as you tighten the sensor tool, even just hand tight. So, it seemed tight, but really was leaking, so the tire was flat. Using vice grips to hold the stem, tightening the sensor tool and then checking with metric soapy water did the trick. I wish I had thought of getting the steel stems when I bought the michelins. It would have been a no- brainer at the time. Specially since the michelins are naturally metric.

WOW! I think I saw somewhere that it's not good to overtighten them. Using the tool I turn it just until I hear the leak stop. It will turn further but I stop there. Have not had any flats. Maybe the sensor's O-ring is not properly installed or maybe a bad sensor.

grampachet · 10-23-2012, 08:31 AM

One of mine worked loose while traveling to Eastern Oregon. The sensor alerted me, I was able to stop and tighten sensor and was only down 15 pounds. I continued on cautiously the remainder of trip until I could replentish the air.
Another time coming through Seattle in summer i was using brakes enough that the temp increased and set off alarm. i changed temp setting later to allow for a higher temp.
We have travelled about 10,000 miles using TST and feel the relief of tire concern has made every dime spent worth it. I still run original China bombs with over 14,000 miles so feel the TST's are a good investment. (now if the darts thrown at me miss my tires I wont be too deflated)

bncinwv · 10-23-2012, 08:37 AM

If you do not have the steel stems, you stand a very, very good chance of experiencing a problem when you are in route. Although the sensors do not seem to weigh very much, they will cause the rubber stems to bend when in motion and this bending will result in the seal being lost, which in turn results in a slow loss of air. The good thing is, your TST will send off an alarm notifying you and you will probably have to put air in the tire to get the screeching to stop. Once you figure out why it is happening, the sensors will be removed from the offending tires. This is based on personal experience and of course the guilty rubber stem just had to be on the inner dually tire on the TV.
Bingo

KathyandDave · 10-23-2012, 02:06 PM

Just to be clear, I didn't tighten the sensor with the vice-grips - I just held the valve stem in place while tightening the sensor by hand with the supplied tool. I did not over-tighten. It rotates about a quarter-turn after the air sound stops and it feels tight to hand. Now, I'm trying to lay my hands on the manual that I left at home, so I can set the upper and lower limits. So much for rushing to get on vacation. But now, I am a day away from home and feeling like I'm actually on vacation!
Steel stems are next...
Dave

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