TST Tire Pressure Monitoring System

[cactusjk]

Thanks for the link. Interested to know if others go with the recommended 20% and 10% high/low settings?

[SteveSueMac]

Originally Posted by cactusjk

Thanks for the link. Interested to know if others go with the recommended 20% and 10% high/low settings?

You're welcome. I personally go with those recommendations. My tires want 50 PSI. My alarms are set for 60 and 45 on the high and low ends. I have the TST TPMS with internal sensors.

[cactusjk]

Good to know. I know some base it on actual TT weight as measured on a truck scale but I prefer to take the easier approach for now.

[NWRVR]

Originally Posted by cactusjk

Thanks for the link. Interested to know if others go with the recommended 20% and 10% high/low settings?

Yes, I inflate to 65 and set the TST to 20% high and 10% low. I have the stem mounts.

[Airstreemer]

I recommend the cap sensors over the flow through because they are more durable and less likely to be damaged.
There are thousands of Airstreams using this system now with no problems

[Airstreemer]

Those are reasonable settings.
It may depend on the ambient temperature of the area you are traveling i.e. Altitude, extreme heat or cold.
Good starting point though

[pcskier]

Thought it might be worth bumping up this thread a couple years later. I am installing my TST 507 flow through system, taking my wheels to the tire shop two at a time to get metal stems attached. Tire place recommends not balancing with the sensor attached to the stem. They say they're too light to matter; and could even throw things off. Which was suspect to me. If they are too light to matter, then how could they be heavy enough to 'throw off the machine."



Any opinions? I'm going to call TST Monday morning to ask them. Tire shop has my first two tires and will do them first thing Monday.


I also will be installing Centramatic balancers when I put the wheels back on, along with solid lug nuts. If not balanced with the sensors on, any possible out of balance condition caused by the sensors would be handled by the Centramitics?

[billb54]

Thanks pc for bumping this thread. Sorry that I have no experience to share on the balancing impact of external sensors. My opinions would be just that, opinions. My interest here is in the installation of the TST 507 Repeater. Would it be a mistake to:

1) install the repeater on the jack tower
2) zip tie the power cord to the TT umbilical cord
3) insert + & - wires into 7 pin connector
4) connect + wire to 12 volt Aux/Charging contact
5) connect - wire to ground contact ?

Wouldn’t this set up make it unnecessary to install a switch for the repeater, as it would only be powered when the TT and TV were connected via the 7 pin umbilical cord?

Thanks,
Bill

[HowieE]

Battery power and ground appear in the umbilical cable from the trailer battery.

The repeater would be on all time.

As for the mounting of the repeater on or near the jack that should not be a problem. The repeater is a high frequency unit and should not be effected by the jack

[billb54]

Thanks Howie

Now that you have pointed it out, it seems obvious.

The female receptacle of any “extension cord” (umbilical) would be hot, if the male end were connected to a power source (battery).

I guess I’ll power from the power jack and install a weather proof switch.

[DavidsonOverlander]

Originally Posted by billb54

Thanks Howie

Now that you have pointed it out, it seems obvious.

The female receptacle of any “extension cord” (umbilical) would be hot, if the male end were connected to a power source (battery).

I guess I’ll power from the power jack and install a weather proof switch.

What about connecting to the running light wire in the umbilical instead of the charge line? It would only have power when you're driving, IF you always travel with your lights on. I do, but I know not everyone does.

[MaineStreamer]

My TST caps (purchased at a NAPA store) on my trailer's tire stems communicate wirelessly with the little receiver adhered to my dashboard by Velcro without any kind of intermediate relay device. The receiver has a cord that plugs into the cigarette lighter.

[larry9000]

Originally Posted by pcskier

Thought it might be worth bumping up this thread a couple years later. I am installing my TST 507 flow through system, taking my wheels to the tire shop two at a time to get metal stems attached. Tire place recommends not balancing with the sensor attached to the stem. They say they're too light to matter; and could even throw things off. Which was suspect to me. If they are too light to matter, then how could they be heavy enough to 'throw off the machine."

Discount Tires balanced our wheels with the flow through sensors installed. They never brought up any issue about doing so.

[CapriRacer]

I just noticed this thread and I think the upper and lower limits posted above are wrongheaded. I think the values ought to be -10% / +15% is wrong. Here's why:


All vehicles ought to have tires that are rated for 15% OVER the actual max loads encountered. In the case of cars, that is pretty much a given. Same for trucks produced since 2008. Trailers? Not so much.


That means the a loss of 10% of the inflation pressure will still have enough load carrying capacity, although it isn't ideal.


Upper limit? There's a rule of thumb that says that normal pressure buildup should not be greater than 10%. That's because at 10% the heat being generated is within the operating range of the rubber over the long haul. - and a 15% buildup is cause for immediate action as that level generates enough heat to cause permanent damage in the short term.

If we also take into account that a 10 degree F increase in ambient temp results in a 3% increase in pressure, the 15% value is a reasonable alert level.

[Tireman9]

Slightly different approach than Capri on setting TPMS.


Aug 1 2017, I did a long blog post (check my profile as I can't post the blog here) where I cover the "why" I do it the way I do.


I set the low pressure level at pressure needed to support the measured load.
For multi-axle trailers, I recommend the cold tire sidewall pressure due to Interply Shear. My Hot pressure warning is set at +10 to +20% of cold pressure. I like Capri's 15% for a max but am concerned about the folks that do not have a 15% margin on load getting many high-pressure warnings and eventually disconnecting the TPMS altogether.
For Max temperature, I am good with 158F. I am writing a series on Internal TPM vs External TPM and have confirmed a significant temperature reading difference. BUT if the load and cold pressure are set correctly this temperature reading difference is not of concern as long as we understand why.

[SteveSueMac]

Originally Posted by Tireman9

Slightly different approach than Capri on setting TPMS.


Aug 1 2017, I did a long blog post (check my profile as I can't post the blog here) where I cover the "why" I do it the way I do.


I set the low pressure level at pressure needed to support the measured load.
For multi-axle trailers, I recommend the cold tire sidewall pressure due to Interply Shear. My Hot pressure warning is set at +10 to +20% of cold pressure. I like Capri's 15% for a max but am concerned about the folks that do not have a 15% margin on load getting many high-pressure warnings and eventually disconnecting the TPMS altogether.
For Max temperature, I am good with 158F. I am writing a series on Internal TPM vs External TPM and have confirmed a significant temperature reading difference. BUT if the load and cold pressure are set correctly this temperature reading difference is not of concern as long as we understand why.

Re: internal vs external sensors - this is a good point to probe. I had the internal sensors and noticed that pressures would rise about 10% - slightly more if temps went up from 70 when I started to 90 a couple hours in. And internal temps rose about 30 degrees above ambient.

My internal sensors batteries seemed to have died and TST sent me external ones which showed the same pressure changes as the internals, but temps would only rise 5-10 degrees above ambient. I assume it's hotter inside the tire than outside where it dissipates but wondering if the 158 degree warning point would be lost on an external sensor?

[Mollysdad]

I have a shiny new 507 system waiting to go on.
My thought with the repeater is to mount it on the propane tank cover (it's waterproof) and adding a two prong connector to the wire and use the Zamp connector while towing.

First, I'll see if I even need the repeater.

Note to TST: What the heck? The new color monitor comes with a suction cup mount, but if you don't want to use it, nothing mates to common mounts. I-grip? No. Ram? No. Go Pro? No.

[SSquared]

Originally Posted by SteveSueMac

Re: internal vs external sensors - this is a good point to probe. I had the internal sensors and noticed that pressures would rise about 10% - slightly more if temps went up from 70 when I started to 90 a couple hours in. And internal temps rose about 30 degrees above ambient.

My internal sensors batteries seemed to have died and TST sent me external ones which showed the same pressure changes as the internals, but temps would only rise 5-10 degrees above ambient. I assume it's hotter inside the tire than outside where it dissipates but wondering if the 158 degree warning point would be lost on an external sensor?

I've run TST 507 external sensor for five years, about 25K miles. The temps mostly track the outside air temp, plus only a few degrees (less than ten). You can also see the influence of the heat of the sun, ten degrees is about the max when you are on the road with high speed airflow outside the sensor.


I don't think you would ever see 158 degrees. Maybe if the tire was on fire.

[Gene]

Originally Posted by SSquared

I don't think you would ever see 158 degrees. Maybe if the tire was on fire.

If you were driving through Phoenix when it is 120˚ at 70 mph, the tires facing the sun might get to 135˚. I expect that is at or over their maximum temp range. If you stop and no wind is cooling them, maybe temps would increase for a while, but 158˚ does seem unlikely.

[Action]

If you are driving through Phoenix and it is 120 degree F ambient temperature, the asphalt can get as hot as 150 or 160 degrees F. The concrete will be 10 to 20 degrees cooler. I have no idea what the inside tire temps would be under those conditions. And my opinion is it would be hot.


>>>>>>>>>>>>>Action