I also have a TireMinder on a TT. This is the second trailer I've used the system on.
Some knowledge - the pressures are +- 4 lbs by their specs and +- 5 degrees by their specs. I think it might be a little more.
However, that isn't important. I check my tire pressures with a good manual gauge before each trip. That is important.
A TPMS isn't for detailed checks of your tires - it is for catching potential problems before they become BIG problems. Such as chronic under or over inflated tires (10% lbs in either direction), slow leaks, overheat from bearings or brakes dragging, etc.
A TPMS won't be any help if your truck or Class A/C kicks up a piece of steel lying in the roadway and it slices your rear tire with a huge gash. You will have a major blowout immediately.
A TPMS gives me peace of mind that I don't have a slow leak from a nail, or such. I've driven thousands of miles with TPMS systems, on the trailer and in my TV. Only once had a warning for low pressure - and it was a nail in the tire.
Once had a warning for high pressure on three tires at the same time. I'd check and adjusted tire pressures in Dallas at 38 degrees, when I got south of Corpus Christi and the temps were in the 90s a few hours later, the high pressure alarm sounded - and the change in temp had raised the pressure quite a bit. (Got to love Texas weather - 50 degree temp changes in a day are not uncommon)
Having a TPMS on duals or a trailer is essential in my opinion. A slow leak tire or a stressed tire by improper hitch angle or weight distribution will show up on a TPMS. If that tire eventually fails at highway speed, you are looking at not only the danger of a blowout and getting stopped, but also the very strong possibility of thousands of dollars of damage to the coach/ trailer.
I know two people in my Good Sam group who said that a $250-300 TPMS was a waste of money. Both have had to spend over $5,000 repairing damage to their 5th wheels in 2011/2012 from a blowout.
We have eight TireMinders and five TST TPMS in the group. Everyone is very happy with their system. One did't like the TireMinder, another didn't like the TST - they swapped and are happy now.
Full-Time 2014 - ????
โNot all who wander are lost.โ
"You were supposed to turn back at the last street."
2012 Ram 2500 Mega Cab
2014 Flagstaff 832IKBS TT