So why just the one tyre pressure setting

[batman1]

Looking through the hand book today for my recently acquired F800GS, I see that I have a different tyre pressure setting for riding one-up and another tyre pressure setting for two-up...normal enough!

I have a similar situation with my car, a recommended tyre pressure setting for two persons and an increased pressure for 4 persons and luggage.

For every other bike and every other car that I have ever owned over the last 40-odd years, my vehicle has had a different tyre pressure setting for light loads and full loads, so I ask myself have the BMW Gods changed the law of physics where the GS-LC is concerned, in that it only ever requires just the one universal tyre pressure setting, loaded or unloaded..... 2.5 bar front 2.9 bar rear...cold.

It's a question that has intrigued me since I purchased my first GS-LC.

Your thoughts gentlemen..

 

[Packer]

Most folk don't even check their tyres let alone adjust them for the kind of trip that is imminent. BM probably just set a best compromise pressure.

 

[Deleted account 211025001]

If you go on a tyre manufacturers site they sometimes (often) recommend a different pressure to that in the bike's handbook. They also only ever give one value, to be used regardless of load.

I reckon Packer has it pretty much spot on and FWIW I always use the pressure rating recommended by the tyre manufacturer if different to that recommended in the hand book.

Andres

 

[Engineer]

Because it doesn't really matter that much in normal use - they now have tyre pressure monitors built in and having multiple settings just complicates matters in detecting low or high pressures before sounding a warning.

PS tyre technology like everything else has moved on so BMW feel confident that all the recommended tyres can now use just the one setting without it causing problems???????

 

[Clifton]

Yes I believe TPS dictates one pressure so the spec is for the maximum load. I found F 33, R 36 to feel best solo and lightly loaded.

 

[Pablo1]

Because it doesn't really matter that much in normal use - they now have tyre pressure monitors built in and having multiple settings just complicates matters in detecting low or high pressures before sounding a warning.

PS tyre technology like everything else has moved on so BMW feel confident that all the recommended tyres can now use just the one setting without it causing problems???????

do you know this for fact ?, sounds bollox to me, never heard of a warning for high pressures, AFAIK only a rapid loss of pressure is going to result in any kind of warning

I'm a bit anal on tyre pressures and always ran the TC at the appropriate pressure for the load, so like the poster i'm also intrigued by this.

No bullshit please only factual statements need apply.

 

[Engineer]

do you know this for fact ?, sounds bollox to me, never heard of a warning for high pressures, AFAIK only a rapid loss of pressure is going to result in any kind of warning

I'm a bit anal on tyre pressures and always ran the TC at the appropriate pressure for the load, so like the poster i'm also intrigued by this.

No bullshit please only factual statements need apply.

You definitely get a warning when it's low - because I have had it! I don't know for certain if you get one when high, but that is not my main point - if you were allowed a range of pressures you would need to tell the system what pressure you want as the reference. I believe that the warning is given when the pressure is 20% down on the recommended so i.e. 33.6 psi compared to 42 as standard this seems a bit too close if you use 36psi as your standard solo setting.

That is my understanding BUT it is easy enough for you to do the research and check for yourself if you doubt what I say

 

[batman1]

You definitely get a warning when it's low - because I have had it! I don't know for certain if you get one when high, but that is not my main point - if you were allowed a range of pressures you would need to tell the system what pressure you want as the reference. I believe that the warning is given when the pressure is 20% down on the recommended so i.e. 33.6 psi compared to 42 as standard this seems a bit too close if you use 36psi as your standard solo setting.

That is my understanding BUT it is easy enough for you to do the research and check for yourself if you doubt what I say

Please correct me if I'm wrong, but I don't believe that all GS-LC's have TPI, is it not only on the TE models that have tyre pressure indicators?

and...

The pre water-cooled bikes T/C's etc that were fitted with optional TPI's still listed both a two-up pressure and a solo tyre pressure???

I'm suggesting this but I have never read a T/C or Oil-cooled or Airhead handbook... An interesting debate!

 

[Engineer]

Please correct me if I'm wrong, but I don't believe that all GS-LC's have TPI, is it not only on the TE models that have tyre pressure indicators?

and...

The pre water-cooled bikes T/C's etc that were fitted with optional TPI's still listed both a two-up pressure and a solo tyre pressure???

I'm suggesting this but I have never read a T/C or Oil-cooled or Airhead handbook... An interesting debate!

Correct but as the top of the range LC model has TPMS as standard then I guess that they decided to keep things simple as the manual is the same across the range??

PS EU rules say that a deflation by 20% from recommended pressure is the limit - that's for cars as far as I can tell but I assume bikes are the same. Much of my information came from an engineer from Bosch in NI who was designing these systems so I think that it is good info.

PPS although there is probably not an upper pressure limit defined in the EU rules it is a trivial software change to add a limit.

 

[Pablo1]

So my car (a bmw) has tyre pressure monitoring and different pressures recommended for different loads, whats different about the bike.
" I believe, its my guess," etc doesnt answer the ops question

 

[Engineer]

So my car (a bmw) has tyre pressure monitoring and different pressures recommended for different loads, whats different about the bike.
" I believe, its my guess," etc doesnt answer the ops question

Does it actually measure and display the tyre pressures in psi or bar? or does it just warn when tyre pressure is very low?

 

[Pablo1]

I see what ur getting at, no it doesnt unlike bike display a value, just detects loss of pressure

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