Tyre Pressure Readings [2011 1200GS]

[johnboy]

Hi

I recently changed my PR3s after 6000 miles rear and 8000 miles front. Comment from RideIn Tyres indicated I had been running the tyres with too low a pressure as I had a stepped profile on both front and rear.

I religiously check my tyre pressure on the dash 2.2 front and 2.5 rear.

So today I checked the pressures with a Draper pressure gauge. Low and behold for the correct pressures the dash reading was 0.3 under. I need a 2.5 and 2.8 on the dash for the correct pressure at the tyre.

A bit pissed off given tyre wear will be greater but also the PR3 tyres squeeze water away best when at the correct pressure!!

At least I am now informed. Maybe worth checking yours.

John

 

[B4ndit]

I was informed by an old inmate of this parish that GSs run best at 37F and 42R with Tourances. Higher than BMW recommend but seems to be sound advice.

 

[Beemerman59]

Are you comparing a cold or warm reading from the TPS? They will read higher when warm.

 

[daesimps]

If I remember correctly the manual says that the dashboard always adjusts for temperature and gives you the pressure the tyres would be at 20 Degrees and not what they currently are. It's cold at the minute so the pressure at current ambient temperature will be lower than what the dashboard says (assuming the tyres are cold and you've not just ridden on them). I hope that makes sense.

Bit of a PITA but does explain (at least partially) the discrepancy between your dash and pressure tool.

 

[johnboy]

Tyres were cold and so was the ambient temperature which was 7C. Hasn't been 20C around these parts for sometime!! Interesting adjustment though as it will lead to an underinflation for a significant part of the year.

If I remember correctly the manual says that the dashboard always adjusts for temperature and gives you the pressure the tyres would be at 20 Degrees and not what they currently are. It's cold at the minute so the pressure at current ambient temperature will be lower than what the dashboard says (assuming the tyres are cold and you've not just ridden on them). I hope that makes sense.

Bit of a PITA but does explain (at least partially) the discrepancy between your dash and pressure tool.

 

[littleredrooster]

TPS should never be relied on as an absolute pressure reading. Its main use is to warn of a pressure loss. I always check both tyres for pressure and condition every 3-4 outings.

 

[littleredrooster]

Tyres were cold and so was the ambient temperature which was 7C. Hasn't been 20C around these parts for sometime!! Interesting adjustment though as it will lead to an underinflation for a significant part of the year.

You'd be surprised what little difference ambient temperature makes to tyre pressures.

 

[The Grey One]

You'd be surprised what little difference ambient temperature makes to tyre pressures.

and you would be surprised at the variation between gauges, best to find a garage with a freshly calibrated gauge to check yours against.

John

 

[Delboy777]

I have 3 digital and 1 old fashioned guage and none of them read the same !!!!

Sent from my SM-T210 using Tapatalk

 

[Bendy toy]

Dig your fingers in the tyre and pumpy up if its soft. It works on my push bike!!!!

 

[Beemerman59]

I've got 2 x digital gauges and one of the pencil type pressure jobbies in addition to the tyre pressure sensors. They're all within a 2psi range of each other which is fine with me. I do seem to get a noticebale difference in pressures depending on the weather temperature - about 4psi between when its warm, say 25 degrees and when its cold, say zero degrees. Difficult to be sure though as there's 6 months between taking those readings! I do know the sensors show another 2psi, sometimes 3psi on both front and back after I've been riding a few miles. Having said that my rear sensor has died and needs a new battery which I'll do next time I change the tyre.

 

[Nick V]

TPS should never be relied on as an absolute pressure reading. Its main use is to warn of a pressure loss. I always check both tyres for pressure and condition every 3-4 outings.

+1

and you would be surprised at the variation between gauges, best to find a garage with a freshly calibrated gauge to check yours against.

John

Couldn't have said it better.

To 'compensate' for varying temperatures, the CANBUS uses a reference temp of 20 deg. C. I've noticed that at 20 deg, the RDC system consistently under-reads the ACTUAL tyre pressures by approximately 0.2 Bar, front and rear. At 15 deg, the under-read is approximately 0.3 Bar.

Personally, I've never seen the point of these stupid 'corrected' values. They serve only to mislead. Give me the true tyre pressure values, please.

I do as above: check pressures using a good-quality analogue gauge, and use the RDC system as an 'early warning' indicator in case I have a sudden pressure loss.

 

[kevmean]

Years ago I remember Neil Tuxworth checking his tyre pressures at Cadwell both before and after a race , I can't remember the exact figures but basically if the pressure difference before and after was too great it was indicating that the initial pressure was too low causing the tyre to overheat .

 

[birdseye]

Charles law applies - pressure is proportional to absolute temperature. So if the tyres warm up by 30C ( ie 10%) and the original pressure was 34 psi then the pressure will have gone up by 3psi or thereabouts

 

[Nunkie]

and you would be surprised at the variation between gauges, best to find a garage with a freshly calibrated gauge to check yours against.

John

Buy a gauge, take it to your local council Trading Standards (Weights & Measures ) office and ask them to test it against their own calibrated pressure thing.
I did this in Hertfordshire ( a good few years ago mind ) and they gave me a chart comparing my gauge's reading against actual pressure, bless their hearts.
Then you'll know it's right !