TPS vs. Gauges

[joeb]

Trying to get tire pressures right. I've used the old fashioned stick type gauge, the dial gauges and the bikes on board TPS read out. No agreement between them.  ? Question. How accurate is the TPS sensor ?

09 1200 GS

THANKS

[lkraus]

Pick one gauge you trust to be consistent - producing the same indication in the same conditions (typically cold, un-ridden). Don't worry about the exact number indicated, it doesn't matter if it matches a standard. Maybe an indicated 40 psi with that gauge provides the traction, wear, and handling you want, maybe an indicated 38 works better. Just make adjustments until you get it right, with that one gauge.   If 40 psi is optimal with that gauge, but the TPS shows 38psi, then 38 is the number you should hope to see from the monitor, in the same conditions.   The real value of a TPS  is to provide a warning of abnormally low or rapidly falling pressure.  

[joeb]

I agree with your TPS  point.  I usually have that up while riding to warn  of a leak .  As far as my riding style goes , I'm not too fussy about tire pressure. Anything short of flat to rock hard can work for me. Of course i try to keep it near the recommended pressure , but if it varies by a few PSI it doesnt affect how i ride. What I'm trying to do now is to see if the recommended pressure increases the tire life , hence the accuracy issue. Thanks for your reply.

Cheers

[Hosstage]

Tire shops may be able to calibrate a gauge, they might let you compare yours to theirs on a tire. Or have them check your tires, then use yours on that tire to compare to theirs. I just occasionally use all the gauges that I have to check pressure and compare them to each other, they all read about the same so just go with what they read. No tps on my bike, but I agree with it just being a reference.

[RadioFlyer]

The pressure given by the RDC is temperature compensated and the gauge reading is not. All explained in the rider's manual.

[Joe Frickin' Friday]

On 7/18/2023 at 2:26 PM, RadioFlyer said:

The pressure given by the RDC is temperature compensated and the gauge reading is not. All explained in the rider's manual.

 

This.  BMW's system measures the actual tire pressure, and then calculates what it would be if the tire were at a particular reference temperature, and shows you that calculated pressure.  So as long as you have no leaks, BMW's system will display the exact same tire pressure regardless of whether you're at a track day in Phoenix in July or parked in a shed in the Yukon in January.

[Dave_in_TX]

42 minutes ago, Joe Frickin' Friday said:

 

This.  BMW's system measures the actual tire pressure, and then calculates what it would be if the tire were at a particular reference temperature, and shows you that calculated pressure.  So as long as you have no leaks, BMW's system will display the exact same tire pressure regardless of whether you're at a track day in Phoenix in July or parked in a shed in the Yukon in January.

That reference temperature is 20 Celsius (68 Fahrenheit).

[dirtrider]

On 7/18/2023 at 12:16 PM, joeb said:

Trying to get tire pressures right. I've used the old fashioned stick type gauge, the dial gauges and the bikes on board TPS read out. No agreement between them.  ? Question. How accurate is the TPS sensor ?

09 1200 GS

THANKS

Afternoon joeb

 

As mentioned your dash RDC is temperature compensated (to about 68°f) so within reason it should show you what your tire pressure would be at 68°f.  Your tire gauge shows actual pressure so you need to manually back-figure the pressure difference to 68°f. A good general rule of thumb is 1 psi change per 10°f.  

 

At 68°f both your dash RDC & your tire gauge should read the same or very close to the same anyhow.

 

At 78°f  your dash RDC should read 1° lower than your tire gauge reads, or very close anyhow.

 

At 88°f  your dash RDC should read 2° lower than your tire gauge reads, or very close anyhow.

 

At 98°f  your dash RDC should read 3° lower than your tire gauge reads, or very close anyhow.

 

At 58°f  your dash RDC should read 1° higher than your tire gauge reads, or very close anyhow.

 

This assumes the tire (and the air inside it) is same temperature as the ambient air. 

 

 

 

 

 

 

[Etienne Lau]

Since my 2010 RT did not have TPMS installed, I've been using FOBO 2 motorcycle. It provides me with 2 readings. One at 20c and the current pressure at the current tire temperature. I don't used BMW recommend pressure because they're based on the riders weight. And they make no mention of the weight.  I use the 10/20% method currently to see what tire wear will be. Prior to switching to my RS 4, I was using 36/42 only got 9000 miles with feathering on the front, rear squared off.  So we shall see.

[joeb]

Thanks for the input. Sorry for the late response as I  just saw these posts . I really appreciate your taking the time to respond to my questions. Wasn't aware that the dash  pressures are temp compensated. Makes sense now.