[MZWIE]

TPMS reads 5 psi low. Keeps giving me warnings. Tried reset, still reads low.

Any way to calibrate properly?

[ChrisK]

My TPMS was always off by 1 pound. What tire gauge are you using?

I use a good Longacre gauge.

http://www.longacreracing.com/produc...al-Tire-Gauges

[CryptoM2]

Longacre are the best. I only trust tpms around town. If I'm going on a road trip I check with a gauge.

[carl44]

mine is a consistent 2psi low(some time 3) VS longacer .carl

[Old Geezer]

Originally Posted by carl44

mine is a consistent 2psi low(some time 3) VS longacer .carl

Same here, although at least one of my Longacres reads high. I rely on the TPMS to indicate differences between tires, but not for absolute numbers.

[MZWIE]

1 psi I can live with. 5 is too much. I have an electronic gauge I use. Can't remember the brand.

[pruettfan]

I wouldn't assume the TPMS is off by 5 psi. Most likely the biggest variable is the tire pressure gauge your using. It is important to note TPMS is not intended to be a substitute for checking your tire pressure with a gauge. My experience is the TPMS tends to be plus or minus 1 psi versus my Longacre gauge. I check pressures regularly when I track, I use TPMS displayed to help monitor my pressures and verify with a manual gauge.

[MZWIE]

I am an instrument and controls engineer by day. I understand this stuff very well. I have 3 different pressure gauges. A simple rod version, a manual round gauge and an electronic one.

These three register the pressure within +/- 1 psi or less. Therefore the issue has to be the TPMS.

While I don't really care about the exact values in TPMS, I do care when it kicks in and intrudes and reducing the top speed available.

[pruettfan]

Originally Posted by MZWIE

I am an instrument and controls engineer by day. I understand this stuff very well. I have 3 different pressure gauges. A simple rod version, a manual round gauge and an electronic one.

These three register the pressure within +/- 1 psi or less. Therefore the issue has to be the TPMS.

While I don't really care about the exact values in TPMS, I do care when it kicks in and intrudes and reducing the top speed available.

It only kicks in if the pressure goes under 28 psi and you have not done a reset. For track days when I run my Cup2 tires that caught me off guard once but I do a reset if I drop my tire pressures significantly prior to a session so it has not been an issue since. It takes about a mile of driving to get it to reset so not something you want to do on track, fortunately it alerted me between the paddock and the grid so I just drove around the paddock like an idiot for 5-10 mins.

[MZWIE]

I know about the reset. If it thinks it is below 28 it will not reset. There must be someway to calibrate to a known value.

[McGary911]

Mines 2 low when I check it. I recently had my 20 year old gauge serviced and calibrated. It’s still reading 2 low in TPMS. I love that old brass gauge. I bought it when I started auto crossing my old 911.

[pruettfan]

Originally Posted by MZWIE

I know about the reset. If it thinks it is below 28 it will not reset. There must be someway to calibrate to a known value.

Wouldn't hurt to bring it to the dealer, can't recall the terminology but when I had a problem with my 3 series they could not figure out they sent data to BMW HQ and were able to determine the issue and resolve the case. Perhaps elevating this issue would find a solution. Since everyone else is within 1-2 psi it seems your system has an issue that is a legitimate concern.

[STK]

The TPMS is off on both our X1 and M2. The X1 by 2-3 psi and the M2 by 3. It's not the gauge(s). With both vehicles having the same problem, I just assumed the system was always underestimated the true pressure . Anyone have a system that's accurate?

It's a sad commentary when we just expect this crap from BMW. I haven't even told BMW. Guess I will the next service.

[pruettfan]

Originally Posted by STK

The TPMS is off on both our X1 and M2. The X1 by 2-3 psi and the M2 by 3. It's not the gauge(s). With both vehicles having the same problem, I just assumed the system was always underestimated the true pressure . Anyone have a system that's accurate?

It's a sad commentary when we just expect this crap from BMW. I haven't even told BMW. Guess I will the next service.

I suppose the other question we should ask is how accurate or not are other manufacturers systems since almost all use the same sensors. My other car is a Honda Accord that has a passive system (no sensors) just alerts when your tire it totally flat based on wheel speed so I don't have a basis of comparison. I do have two sets of wheels (track and street) both of which have sensors OEM in street and Continental in the track so I will take a look at both and see if there is a difference by chance. Pretty sure Continental makes the sensors for BMW so I doubt I will see a variance.

[rich8566]

Originally Posted by MZWIE

TPMS reads 5 psi low. Keeps giving me warnings. Tried reset, still reads low.

Any way to calibrate properly?

Same here. Mine is low by 4 psi.

[matty_f]

Sub’d in case we get a solution. I would be so happy if I could get mine to read 5 psi too high to avoid comfort mode on the track.

[David1]

My TPMS is only about a pound off when cold.

[rich8566]

Originally Posted by matty_f

Sub’d in case we get a solution. I would be so happy if I could get mine to read 5 psi too high to avoid comfort mode on the track.

Mine reads too low. i.e. 33psi TPMS reading is really 37psi.