Minimum Tire Pressure in 4x4 that wont trip TPMS?

Looking to see if anyone knows minimum tire pressure front/rear that wont trip the TPMS?

Have noted that i'd like a slightly softer ride when running around without load.

MB Service Tech told me that if you ~6 lbs. less it will trigger the warning. I have not tried it to see though.

You can reset the TPMS to stop it from tripping if you've reduced pressure in your tires, but there's a catch: If you drop the pressure too low, you can reset the TPMS so that it doesn't complain about the low pressure, but the tires will heat up too much as you drive, and the pressure will rise significantly. When it does that, the TPMS will tell you that your pressures must have been too low because now they've gone up too much.

What counts as "too low" will vary depending on your load at the time. An empty van can take a much lower pressure than a fully laden one. The only way you'll be able to find out is by playing around with the pressures yourself. As a starting point, I was running 45 front, 55 rear with a nearly empty van (if I remember correctly). No TPMS issues until I picked up a pallet of stuff. Then, the TPMS kicked in after I'd been driving on the freeway for a while and the rear tire pressure was up to ~63.

I picked up a screw on the highway and my back rear dropped to 61psi when the light came on. Wish you could set the level you want but it was nice to have the system letting me know somthing was up.

ktm805 said:

I picked up a screw on the highway and my back rear dropped to 61psi when the light came on. Wish you could set the level you want but it was nice to have the system letting me know somthing was up.

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Check your owners manual. You can reset the value. It was a life saver for me as well.

KentuckyWR said:

MB Service Tech told me that if you ~6 lbs. less it will trigger the warning. I have not tried it to see though.

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I'm certain the TPMS operation is outlined in the operator manual.

What the tech told you sounds like how most TPMS systems work. My limited experience with other brand vehicles is that a value is programmed in as "normal". From there a certain number of pounds pressure deviation or a percentage change from setpoint will trigger the alarm.

It must be a real lifesaver for dually rigs.

vic

They don't come standard on duallies though. I bought an aftermarket one for the RV.

Yes, whatever pressure you want can be set for the TPMS. I just reset one on a '12 last week. IIRC, you had to scroll through the dash displays until you came across the tire pressures and then hold one of the buttons down until it beeped. That reset the TPMS to think that thr current pressures were now normal. So you can lower the pressure down to ~10 psi and then readapt the system to think that's normal. Then when you air back up, reset it again to the highway pressure. It's really easy.

To answer the question. The minimum pressure the TPMS can be set at is 3bar which to USA people is 43psi. This is way to high for most driving conditions so you may as well turn it off. How do you turn it off? I am still looking for a tidy way of doing it. Eric.

You put a piece of electrical tape on the dash in the sight line of the TPS warning light... ;-)


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AGENCY:� National Highway Traffic Safety Administration (NHTSA), DOT.

ACTION:� Final rule.

SUMMARY:� This final rule establishes a new Federal motor vehicle safety standard (FMVSS) requiring installation of a tire pressure monitoring system (TPMS) capable of detecting when one or more of a vehicle�s tires is significantly under-inflated. This final rule responds to a mandate in the Transportation Recall Enhancement, Accountability, and Documentation (TREAD) Act. This final rule requires installation in all new light vehicles of a TPMS capable of detecting when one or more of the vehicle�s tires, up to all four tires, is 25 percent or more below the manufacturer�s recommended inflation pressure (placard pressure) or a minimum activation pressure specified in the standard, whichever is higher.