Is the TPMS off by a few pounds?

At least?

In order to get the TPMS to register the correct 36/42psi I have to fill the tires a few pounds above, according to three different tire gauges. On digital, and two analog. Has anybody else noticed this or am I just late to the party?

captainmarko said:

At least?

In order to get the TPMS to register the correct 36/42psi I have to fill the tires a few pounds above, according to three different tire gauges. On digital, and two analog. Has anybody else noticed this or am I just late to the party?

Click to expand...

This thread seems to cover the subject comprehensively:

https://f800riders.org/forum/showthread.php/321215-TPMS-faulty-or-needing-reset?highlight=TPMS

RadioFlyer said:

This thread seems to cover the subject comprehensively:

https://f800riders.org/forum/showthread.php/321215-TPMS-faulty-or-needing-reset?highlight=TPMS

Click to expand...

Excellent! Thank you very miuch!

My 16RS now shows 4#'s lower than the air pressure I put in the tires. Knowing this, when they read 32/38, I know they are off by 4#'s. Used to regularly be off 2#'s, now it's 4#'s lower on both numbers than actual pressure in tires.

I'm not all that concerned with it.

On my 1200GSA the displayed pressures, using the older style sensors, were consistently within one PSI of what my gage read. On my 1250GSA, using the new style sensor, the displayed pressures are consistently 2.5 PSI low. Consistency is the most important aspect.

Because the TPMS readings are temperature compensated to what,... 68 F, then the further away from that number (one way or the other) the ambient temperature actually is when using your regular tire gauge as a measure, and therefore the temperature of your tires sitting in it's parking spot for some period of time are equalized with the air, the further apart the readings will compare. BMW must think that we as riders don't actually ride our bikes in any other weather than mid-60s. I don't get the logic. After a few good accelerations and/or brakings my tires warm up and then the TPMS values move up a few PSI with zero change in the air temperature.

The only value I see in the TPMS is when relative value changes quickly, indicating a problem. Otherwise, fill your tires to what you think will be a stable value doing whatever it is you do, (mentally add a couple of PSI to that) and then just watch for changes on the display that may mean trouble.

Rainman48 said:

The only value I see in the TPMS is when relative value changes quickly, indicating a problem. Otherwise, fill your tires to what you think will be a stable value doing whatever it is you do, (mentally add a couple of PSI to that) and then just watch for changes on the display that may mean trouble.

Click to expand...

Exactly!

Joe

Rainman48 said:

BMW must think that we as riders don't actually ride our bikes in any other weather than mid-60s. I don't get the logic.

Click to expand...

BMW didn't pick that temperature. Twenty degrees centigrade is the standard definition for "cold" pressure used by virtually all tire manufacturers and the US DOT and its equivalent in the European Union and elsewhere. Any decent temperature compensating TPMS standardizes to 20C or 68F.

My experience is that the TPMS shows the cold pressure I set the the tires at but does not show the increased hot pressure after riding for a bit. It's annoying as my SD GT accurately showed cold and hot pressures. Still, the real advantage is a warning of a puncture before the bike gets out of shape.

My 2 cents. Inflate the tyres correctly, check if correct with digital agauge that you trust. Then go and ride

Ride enough times to learn the nuances of the pressure readout on the dash under a variety of conditions, then worry about more important things.

The TPM units read 2-3 psi low on my 17 r12rs. This is the same as it was on my 13 k13s. I don't think anyone expects the TPM to be an accurate indication of tire pressure. Like others have said, it's to warn us when there is a serious loss of pressure, both catastrophic and slow steady leaks.

Low Reading Also

2018 R12 GS with sidecar and automotive rim and tire on the rear. TPMS reads 3.5 to 4 psi low. Problem is I should have 30 to 32 psi, but to avoid Low Tire Warning I need to have 35 to 36 psi actual. Everyone I ask says the setpoint can not be changed. Is there any way to disable the warning for the rear tire only? Alternatively is there a sensor which reads 4 or 5 psi higher than actual?

My TPMs read bang on the money as compared to a calibrated tire pressure gauge.