accuracy of tire pressure monitor system vs. good gauge

[ca1ic0cat]

Pumped the tires up yesterday for a ride, used my Accugauge to check the pressures, left them 1psi over.  Got on the bike and rode a few miles, flipped to the TPM on the dash.  Reading 2psi low.


This seem to be consistent no matter which gauge I use.  Is the TPM 3psi off on other people's bikes?  Short of getting a NIST certified gauge to check which is on which should I assume is accurate? :alas:

[B787MECH]

As the bike TPM reads in Bar, how did you know it was 2 psi out?


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[David.]

1 Bar = 14.5 psi.

Accu-gage quote, "The mechanical accuracy rating is ± 2% from 30% to 60% of scale and ± 3% below 30% and above 60%."

At +/- 3%, 36 psi could vary between 35 to 37 psi & 42 psi could vary between 41 to 43 psi.

The on board TPM system is compensated for temperature.



Perhaps the TPM system is best used for early detection of a falling pressure due to a puncture, rather than accurate tyre pressure setting.

[Casbar]

As the bike TPM reads in Bar, how did you know it was 2 psi out?


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The TPMS can be set to read in bar or psi by BMW. Some countries outside Europe have the bikes delivered in psi, including the US. So that is how he knows

[bandytales]

Pumped the tires up yesterday for a ride, used my Accugauge to check the pressures, left them 1psi over.  Got on the bike and rode a few miles, flipped to the TPM on the dash.  Reading 2psi low.


This seem to be consistent no matter which gauge I use.  Is the TPM 3psi off on other people's bikes?  Short of getting a NIST certified gauge to check which is on which should I assume is accurate? :alas:

The TPM's on the bike are purely as a safety aid to warn you of deflation. They are not there as a replacement for your accurate garage pressure gauge. If you treat it in this way, you will get away from this technology paranoia that is taking over.
Years ago, we checked the tyres weekly at the petrol station or if the bike FELT wrong. Use 'feel' more.
Years ago we didn't have oil temp gauges, so we didn't worry about oil temps. We listend to our bike and went by 'feel'
Come on, use the force!

[Our Gee]

Well said Sir.

[Ganesh]

+1, can tell if they go soft on me or if I over inflated by the ride and I don't rely on the TPMS for the reading more a significant pressure drop. a case of getting to know the bike.

[Casbar]

+1, can tell if they go soft on me or if I over inflated by the ride and I don't rely on the TPMS for the reading more a significant pressure drop. a case of getting to know the bike.

I don't even have the pressure displayed, I would rather see range left in the tank. I check my tyre pressures weekly and rely on the TPMS to tell me if I have a deflation, which it did the last time I had a puncture, so does the job

[bandytales]

I don't even have the pressure displayed, I would rather see range left in the tank. I check my tyre pressures weekly and rely on the TPMS to tell me if I have a deflation, which it did the last time I had a puncture, so does the job

Me the same.

[BeeJay]

+1

[gogs01]

I don't even have the pressure displayed, I would rather see range left in the tank. I check my tyre pressures weekly and rely on the TPMS to tell me if I have a deflation, which it did the last time I had a puncture, so does the job

I find the TPMS useful on a long trip.  I don't have it showing all the time, but scroll through once or twice between tank refills. On previous RTs I've found it to be very accurate and consistent when measured against my assortment of pressure gauges, the latest bike seems to be slightly less accurate and consistent but perfectly good for early warning of a tyre issue.