Tire Pressue Monitors - Onboard vs Hand Held

[longislandcampe]

My 2013 Ram 1500 has the built in tire pressure monitoring and I received a low pressure warning this week so I finally got around to airing them up. I had just purchased a digital inflator/gauge and was curious about using it. Gauge/inflator

I pumped up the tires to the suggested 39 PSI on the gauge but when I went to look at the dashboard it read 40. Also, one of the tires read 41 on the dash. I kept fiddling with that tire but it would go from 39-41 and I couldn't make it hit 40 at all.

This just got me wondering about which system to you think is more accurate?

[Grit_dog]

I'd say find another mystery to ponder.

[longislandcampe]

The gauge is more for filling my bike tires and camper tires as opposed to my truck tires. It especially holds true when we camp on the beach because we need to air down all tires to about 20 psi and then air back up when leaving the beach. The truck tires are easy due to the built in monitoring system. The trailer tires are air em up, test. Air em up, test, air em up test. ****, deflate a bit and test. lol

[pawpaw47]

My truck TPMS and the TPMS system I mounted on my trailer tires are usually 1-2 lbs. off from each other. I don't worry about it. I think that's close enough.

[Miles_Away]

I use both. The on-board TPMS (truck and trailer) are the best thing since sliced bread and give you a real time / all time reading as to the status of your tires. However, unless you enjoy running back and forth from the tires to the dash board to check your air pressure when airing up your tires you need a hand held gauge as well. They may all read slightly different (withing one or two pounds) but as stated above, it's no big deal.

[DrewE]

It sounds to me like they're both accurate enough for what they are being used for. To find out which (if either one) is more exactly correct, you would have to check against some known accurate standard.

Typically the digital gauges are quite accurate.

[Shearwater]

Tire pressure gauges are like thermometers - you only want one if you want the answer. If you have two, you are never sure.

I'm sure you could get more accurate gauges but they would be a lot more expensive and a difference of 1 lb pressure in a tire is not significant.

[westend]

I'd suggest to go with your truck gauges since that's what you'll be looking at. The difference in pressures between the two is not really an issue. Your tires will heat up and rise in pressure more than the 1 lb in pressure difference after you drive a few miles.