New Truck/New Trailer - TPMS for both

[Bondi19]

Have a 2020 silverado 2500 with tpms advanced trailering system. In a week will be towing a new 24RLS. The truck trailering system can add 4 sensors to the trailer tires so we can monitor them also. Want to know if anyone else is using this system. The Chevy accessory page has the sensors for $150 for two! so $300 for all four. Or should I just buy a reg. aftermarket system?

[Highway 4x4]

I have the TST system and it's great. But I would use the factory system as it should be covered under the warranty.

[Blazing zipp]

If you went with the factory system, would it keep one more item off the dash area? We like our TST set up, but if we buy a rear camera and we already have a GPS and TST, it's going to be crowded, what with phones, water bottles, SNACKS, etc.

[Randy the sly old fox]

I thought the new trucks included sensors for the trailers.

[brulaz]

They are definitely dinging you for those TPMs. But I would buy them for the (as mentioned) integration, warranty and convenience. I presume they just screw on to the valve stem like my TSTs?

[LeisurePursuits]

I have what sounds like a similar system on my F250. The trailer wheels have TPMS sensors installed just like the truck. Near the trailer axles is a wireless sensor to read the TPMS and then sends it wired to the truck. From my dash I can see all 8 tire pressures. My setup also includes a rear trailer camera that uses the same pigtail as the TPMS. When I hook up there are two pigtails to connect vs the normal 1 that everyone has. Very clean setup. Was pricey though, so it may not be worth it depending on your finances.

[litzdog911]

One key benefit of after-market TPMS systems like TST is that they also provide tire temperature, not just pressure. Increasing temperature is an early warning of serious tire problems.

[fisher99]

That's pretty steep for the sensors, but then again a good TPMS system will cost about that (or more) and you have more clutter on your dashboard. I'd definitely go with the Chevy sensors that integrate into your truck's TPMS. I'd probably even get rid of the TST TPMS that I already own if I had the integrated option with my truck.

Note that the Chevy sensors are not the type that just screw onto the top of your trailer's existing valve stems. You will need to dismount the tires and replace the existing stems with the Chevy stems. Still worth it though, in my opinion.

[bob26rls]

One warning about the TST system. Install the repeater, even if things seem to work without it. You'll want the extra signal margin.

The sensors only seem to update about every 5 minutes -- unless the alarm parameters are exceeded. The problem is that the display doesn't indicate if a reading has been missed, possibly even 2 readings, so you might not know for 10 minutes or more that you're not getting updates. Without the repeater you might miss important temp/pressure trends, and not even know it.

I discovered this by monitoring the TST display after leaving the campground to go into town. The display was merrily showing me good tire pressures for many miles, even though the trailer was still back in the CG, far, far away.

[brulaz]

Originally Posted by bob26rls

One warning about the TST system. Install the repeater, even if things seem to work without it. You'll want the extra signal margin.

The sensors only seem to update about every 5 minutes -- unless the alarm parameters are exceeded. The problem is that the display doesn't indicate if a reading has been missed, possibly even 2 readings, so you might not know for 10 minutes or more that you're not getting updates. Without the repeater you might miss important temp/pressure trends, and not even know it.

I discovered this by monitoring the TST display after leaving the campground to go into town. The display was merrily showing me good tire pressures for many miles, even though the trailer was still back in the CG, far, far away.

And I lost a wheel and only knew about it because somebody flagged me down. The TST started beeping long afterwards when we were on the side of the road trying to fix it.

But not sure how a repeater would fix this? Does it ping the sensors more frequently?

And are the built-in OEM systems by Chevy etc. any better?
One issue with the OEM systems with their built-in sensors is that rotating and changing tires might be more difficult. With the TST add ons, you just remove the sensor and put it back in the same tire position.

[bob26rls]

Originally Posted by brulaz

But not sure how a repeater would fix this? Does it ping the sensors more frequently?

The sensors run off of a battery that has to last a year, so there's no power-draining bi-directional communications (i.e. pinging) during normal operation, only during setup. Instead, according to the manual, they monitor pressure and temperature on a fairly regular basis, every 12 seconds, but only transmit that status every five minutes -- unless a pressure or temperature falls outside of the alarm parameters programmed into the sensor during setup. It's not clear if an alarm conditions increases the rate of updates after the initial alarm, but based on your lost-wheel experience I would say it probably doesn't. Still, if the sensors do send out even one update based on alarm conditions, that's better than other systems where the alarming is completely in the receiver/display.

The repeater simply listens and re-transmits the sensor data, greatly increasing the odds that the display will hear the sensor updates. That's it. The point is, with the way it appears they've designed the system, you could be missing half of the updates and never know it. With the repeater you're much less likely to miss an update. If TST ever redsigns the display, it would be nice to have a red stale-reading indicator/icon. One nice feature they do have on the display is an icon that lights up when a repeater is detected. That will at least tell you if you've remembered to turn on the switch controlling repeater power.

It's quite a technical challenge to transmit data from a sensor to the display. Because of battery lifetime constraints the sensor transmit power has to be very low, and because of size, the antenna has to be very small and therefore very inefficient. The sensors transmit at 433 MHz. So, if you know anything about radio antennas, you know that a nominal 1/2 wave antenna at that frequency would be 13" long. Obviously the sensors don't have antennas anywhere near that large. Even the repeater and display antennas are physically short. However, the repeater's transmit power isn't power-supply constrained as it's not powered by a coin-cell battery.

BTW, TST recommends installing the repeater in a battery box. With our fiberglass caps, which are transparent to radio signals, we have more mounting options than aluminum trailers. As I don't have the trailer on shore power when in storage, I mounted the repeater next to the main battery switch and pulled power off of the switched terminal. I pulled ground off of a wire going to the storage compartment light above the battery switch. Installed in that location I was easily able to get readings inside the house through an outside and two inside walls. I haven't tested the range with the truck. I do have the aluminum diamond plate on my cap, but as it's not grounded, it doesn't seem to block the repeater's signal. If I had to do it again, I would install the repeater next to the light at the top of the storage compartment, and pull both power and ground off of the light.

[LeisurePursuits]

Originally Posted by brulaz

And I lost a wheel and only knew about it because somebody flagged me down. The TST started beeping long afterwards when we were on the side of the road trying to fix it.

But not sure how a repeater would fix this? Does it ping the sensors more frequently?

And are the built-in OEM systems by Chevy etc. any better?
One issue with the OEM systems with their built-in sensors is that rotating and changing tires might be more difficult. With the TST add ons, you just remove the sensor and put it back in the same tire position.

You rotate your trailer tires? I had never considered it.

[brulaz]

Originally Posted by LeisurePursuits

You rotate your trailer tires? I had never considered it.

Once one starts showing unusual wear I rotate. With rotating I am getting about 35K miles per set of tires. And when the tires are replaced, I also replace all the worn spring bushings, which seem to be cause of odd tire wear.

[brulaz]

Originally Posted by bob26rls

The sensors run off of a battery that has to last a year, so there's no power-draining bi-directional communications (i.e. pinging) during normal operation, only during setup.

...

Thanks bob. Very informative.