robandbarb Report post Posted September 30, 2017 I just installed a Tire Minder tm-77. I checked tire pressure and adjusted to proper pressure with a Tire Minder tmg-aaa RV digital guage. The pressure on my tm-77 unit does not match the pressure with my tire minder gauge a difference of 1 to 7 lbs on my RV. The car I am towing is pretty actuate on pressure with tire minder unit vs the tire minder digital pressure gauge . Any help on this would be appreciated. We are leaving for Thor rally Sun. morning in Goshen. Share this post Link to post Share on other sites
elkhartjim Report post Posted September 30, 2017 The sensors are ± 3 - 5%. If you have one registering 3% lower and one registering 5% higher, you could have a sizable variance in pressures. Share this post Link to post Share on other sites
desertdeals69 Report post Posted September 30, 2017 One of the important things is that it will give you information of a variation in pressure of each tire as you run. Share this post Link to post Share on other sites
wildebill308 Report post Posted September 30, 2017 Assuming you have weighed the coach and set tire pressure to the tire manufacturers chart + 10% or I just use + 10 lbs as it is easier. I would use a known accurate gauge to set the base pressure and the record what the Tireminder read. See how much it changes on the trip. Bill Share this post Link to post Share on other sites
tireman9 Report post Posted October 14, 2017 I have addressed the topic of TPMS "Accuracy" HERE I have also done some calibration checks after my seminars at a few FMCA Conventions using my digital gauges that are accurate to =/- 0.5 psi when checked against ISO laboratory gauge What we see is that about 10% of the gauges are off by more than 5 psi at the 80 psi level I use as a standard Some are off by 10 psi or more ! NOTE simply paying more for a gauge is no confirmation that the gauge is accurate. My three "Master gauges only cost $10 each HERE is a post on my test results. Share this post Link to post Share on other sites
wayne77590 Report post Posted October 14, 2017 I don't worry about what the TPMS says I inflate accordingly and use a calibrated gauge. Then I look at the TPMS and it will always read differently. From that point on it is nothing more than a reference and if something does go wrong with a tire it will notify me according to the values I set. Any gauge is really nothing more than a reference point, even the calibrated ones but they are real close to being correct. Reference point is all I need. If I set a tire to 110 psi and the gauge reads 108 psi then when the gauge reads 108 psi i know there is 110 psi in the tire. + or - 10% from either value is only about 1 psi difference. Just a reference point. It's still frustrating that the TPM can't be more accurate. Share this post Link to post Share on other sites