Community Forums

Alpine36 · 09-13-2022, 01:54 PM

Just purchased a new TST507 system for our coach and toad, 10 sensors total. After watching their installation video and carefully pairing the sensors, setting low and high pressure parameters, leaving temperature parameters alone and installing the repeater I'm thinking all is well, everything went without a hitch.
The repeater even picked up the toad parked in the carport about 100' away.
Woohoo, so off we go on about a 700 mile "local" road trip east, all the while explaining to DW why spending six hundred bucks on a reliable tpms was a good idea.

The first leg of about 200 miles went without a hitch.

Thirty miles in to our second leg we get a low pressure alarm on the RR toad tire. It was still displaying 36psi on suspect tire, and a temp of about 85 degrees. The alarm cleared in about one minute, but I still pulled over to check things out, all ok. Just a fluke I'm thinking.

Yesterday, traveling on I90 Snoqualmie Pass at 65 mph I get another low pressure alarm on the LR inner dual. The audible alarm and low tire icon did not clear. It showed 90 degrees temp and 107psi. Ok, pull over in the chain up area and check it out. No trouble found. Come back inside and the monitor is quiet but the low pressure icon in still on. Is this normal operation? Have others had false alarms randomly for no particular reason? I went with TST because of all the "false alarm" complaints with other brands. I'm now wondering if this was a wise investment, as false alarms tend to get ignored eventually.

Here's the parameters set...
Coach, target psi as per manufacturer and CAT scale weight 95psi front and rear. Low pressure alarm set 85psi. High pressure alarm set 120psi.
Toad target psi 35 front and rear. Low pressure alarm set to 28psi. High pressure alarm set to 50psi.

Thought I'd ask here first before placing a call to TST.

Thanks, Mike

Ray,IN · 09-13-2022, 02:08 PM

TST's customer service is excellent IMO, give them a call. I bought s TST system in 2005, had a problem and called. The office was closed that Saturday afternoon so I left a message. Sunday afternoon the owner called from his cell phone while on a golf course to help with my problem.
It might be something as simple as low sensor batteries. It doesn't happen often though; I buy cheap 2032 batteries from flea markets and they last anywhere from a year to 3 years, but once in a great while I install a new battery and it only lasts a few weeks.

Alpine36 · 09-13-2022, 02:20 PM

Quote:

Originally Posted by Ray,IN

TST's customer service is excellent IMO, give them a call. I bought s TST system in 2005, had a problem and called. The office was closed that Saturday afternoon so I left a message. Sunday afternoon the owner called from his cell phone while on a golf course to help with my problem.
It might be something as simple as low sensor batteries. It doesn't happen often though; I buy cheap 2032 batteries from flea markets and they last anywhere from a year to 3 years, but once in a great while I install a new battery and it only lasts a few weeks.

Thanks Ray,
I did purchase extra 2032's. Maybe I'll start there....

Swipular · 09-14-2022, 05:55 AM

I was getting false alarms until I installed the repeater. The only false alarm I get now is the driver front tire on the toad. I get a heat warning on it from time to time and the tire checks fine when I stop. I believe that is caused by the exhaust confusing the sensor.

I know you installed your repeater but it does sound like a communication issue. So batteries could be the issue.

Alpine36 · 09-14-2022, 10:00 AM

TST did mention some indoor/outdoor thermometers operate at 433mhz and could cause occasional communication issues. Just checked ours, yep, 433mhz. So I'll remove that and check/replace all the original installed (one week of use) sensor batteries and report back. I could understand the repeater being suspect if the alarms were toad only. Amazingly, the Jeep is now parked inside the garage 75' away from the coach parked outside. It's picking up the toad sensors with no problem.
Thanks for the replies,
Mike.

oneknight · 09-18-2022, 04:14 PM

Your parameters are too tight.
I set my high pressure so I'll never get an alarm. 150 or so.
Low pressure to a "just dangerous" number. 85 in front, 75 in back.
Temp is a never mind.

I want to hear from it if my pressures suddenly drop to zero.

Sent from my moto z3 using iRV2 - RV Forum mobile app

Archer2 · 09-18-2022, 05:34 PM

I have to respectfully disagree about not paying attention to the High Temperature limit settings. I try to set my Hi-Temp alarms to about 160F. This is to give me at least a chance of getting my attention in the case of a failure of my toad breakaway switch applying the brakes or some other malfunction that could generate drag on the toad tires. A high temp alarm is something I take seriously.

Alpine36 · 09-18-2022, 06:36 PM

I don't think the high pressure parameters are set too "tight" at 120psi for a 95psi cold pressure. At least not according to TSTs guidelines.
I've never seen anything over 108psi "warm"...and my maximum tire inflation recommendation is 120psi. I'd sure like to know if I'm exceeding max inflation. The odd thing is, the monitor never indicated low pressure, high pressure or over temp, just an audible alarm and the low tire icon.
High temp and high pressure monitoring is important as an indicator of serious mechanical problems. We're leaving Wednesday for another road trip, so time will tell.

NXR · 09-25-2022, 09:03 AM

Quote:

Originally Posted by Alpine36

Thirty miles in to our second leg we get a low pressure alarm on the RR toad tire. It was still displaying 36psi on suspect tire, and a temp of about 85 degrees.

...

Toad target psi 35 front and rear. Low pressure alarm set to 28psi. High pressure alarm set to 50psi.

Quote:

Yesterday, traveling on I90 Snoqualmie Pass at 65 mph I get another low pressure alarm on the LR inner dual. The audible alarm and low tire icon did not clear. It showed 90 degrees temp and 107psi.

...

Coach, target psi as per manufacturer and CAT scale weight 95psi front and rear. Low pressure alarm set 85psi. High pressure alarm set 120psi.

To clarify, in both cases, the TST Low Pressure alarm went off at pressures well above the alarm threshold?

It sounds like either you have a defective display unit or you do not have the alarm thresholds set where you think they are.

I take it you have double-checked the alarm threshold setup? I vaguely recall a similar issue when I got my TST 507. I thought I had set the alarm thresholds correctly but when I double-checked, nope. I missed a step somewhere.

Ray

NXR · 09-25-2022, 09:16 AM

Quote:

Originally Posted by Alpine36

I don't think the high pressure parameters are set too "tight" at 120psi for a 95psi cold pressure. At least not according to TSTs guidelines.

The TST guidelines do not take into account what type of RV you're using but I agree, your numbers seem appropriate.

Quote:

I'd sure like to know if I'm exceeding max inflation.

There's no such thing as long as your cold pressures are set correctly and the tires are not overloaded. The pressure molded into the tire sidewall is the minimum pressure required to fully support the maximum design weight limit of the tire when cold, nothing more.

Tire designers take into account how much the tire pressures will increase with use.

Quote:

High temp and high pressure monitoring is important as an indicator of serious mechanical problems.

On a trailer, maybe, because a dragging brake or a failing wheel bearing can raise the temps. But on a motorhome the wheels are so large and the tire area is so large that the temperature indicated by an add-on TPMS is pretty much irrelevant. That's why the default temp setting is so high, close to 160 degrees F. The large wheel is a giant heat sink dissipating heat.

What matters is the temperature of the rubber in the layers of the tire, not the temperature of the air inside the valve stem or how much the TPMS sensor heats up from the direct sun.

A TPMS is best used as a trend monitor. If all tires are behaving the same as they always have and all tires are behaving the same as the other tires, the absolute numbers and their variations are not that important.

Ray

scotttkd · 09-25-2022, 09:22 AM

I know I am in the minority on this forum but I had issues with the TST system. Even with the range extender I would get loss of signal alerts constantly. Sometimes 200-300 miles with no issues, then a rash of LOS of alerts, sometimes LOS alerts right from the start, and then it would settle down for the rest of the day. Each time I got alert I would pull over and check and nothing wrong, no PSI issues, etc. I tried multiple locations for the extender, new batteries, moving the offending sensors and nothing seemed to fix it. It got to the point where I began to ignore the LOS alert and just drive on. Big mistake as I had an actual tire go down because the entire valve stem extension had failed. Bottom line after that tire was lost and its partner shredded on the highway I swapped the system out for a TireMinder. Extender in the same location as previous system, no LOS alerts. A little trouble getting the high and low ranges to work for me (they do theirs differently than TST) but now I have it dialed in and no reliability issues. I think every brand has its fans and haters, I bought the TST because of comments and recommendations on this forum, but it didn't work for me and cost me dearly. My 2 cents.

Parafango · 09-25-2022, 06:25 PM

I've had the TST system for about 2 years.
At first, they were on floppy valve stems on the TT. While the sensors worked fine, I noticed wear spots on the wheel, so I changed to solid valve stems.
During this last trip from SW Idaho to Key West, I noted some high pressures and temps, mostly on the side of the trailer in the sun. Coincidence?
I also put TST sensors on the truck tires, because I've heard from others, that the TST sensors respond faster than the OEM ones, Well, if I didn't have the sensors already, I wouldn't have purchased them for that reason, but I had them so why no use them...
I wish the TST system would let you set separate pressures and temps for the tires. It seems that there is one high/low setting for temps and pressure, and that's it. So this next parts is partially my fault, I replaced the Costco tires load range D with Good Year Endurance load range E, but didn't spend the extra to get the spare tire changed at the same time... So they are different pressure ranges between the two brands and I would get alerts in the morning telling me the pressure was too low in the spare, because the pressure was set for the Endurance tires which were a higher pressure. I'd just reset and keep an eye on it
I spoke to TST before I left on the trip because I saw a 3-5 lb difference between the TST monitor and the stick pressure tester I was using. I set the pressure to the stick and made a mental note that the 3 - 5 lb was within tolerance according to the TST tech desk.