URGENT tire pressure question please!!
 

So as some of you know, I recently acquired a 2005 645 cabrio (with sports package standard 19" rims) (Pix coming soon!!)

It needed new tires though, and I opted out of the expensive and not-so-good OEM Bridgestone run-flats. Instead, I purchased a set of Goodyear Eagle F1 tires.

Thing is though, neither I nor the tire installer were sure what tire pressures to use!! The door jamb and owner's manual specify the ludicrously high PSI settings for run-flats which obviously are inapplicable to the GY Eagles, while the GY Eagles recommend something around 29/31 F/R which is what the tire shop said they set them to.

HOWEVER: just now after driving around for a bit I decided to check the pressures with my cool sharper image color-coded digital tire gague lol. Strangely, I couldn't get it to read the pressure from any tires at first -- couldn't hear any air at all and thus no reading. Finally, however, one of the rear tires gave an instantaneous reading of ... ready for it? 55 PSI!!!!!

The max tire pressure indicated on the sidewall is 51. What's going on here??

And more importantly, how am I to figure out what the optimal tire pressure is for these GY Eagle F1 tires when all the published information for the car pertains solely to the run-flats??

Thanks!!

Cros, this isn't rocket science for running tars on the street, imo...
check what the suggested listed tire pressure "spread" is in the manual
or, the sticker on the door: then figure in 1 person, 2 people, fully loaded, etc.,
as to your normal driving conditions, and fill to that rec'd level.

RFTs other than stiffer sidewalls and a few tweaks in the tire carcass
and sometimes tread design, are not an alien species...fill to rec'd level and
enjoy the car...and, chill on the obsession, lol!

That 51 was way overfilled...somewhere in the 32-39 psi ought to be
right in the ol'zip code, imo.
GL,mD

PS/Edit...wait for the 3 pages of posts on what everyone else is running, lmao!

PSS...check in morning when stone cold and pump them to what the rec'd is.
A decent digital gauge or, even an on the ball pencil gauge works well.

32psi is about the norm for every street tire and automaker (including BMW). Just use that.

hahah thanks guys :D *done obsessing* :)

Remember that the air inside the tires will warm up and pressure will increase as it does so. Thus, an accurate reading would be when the tires are stone cold. 55psi when warm is too high though!

Oh, don't forget to reset the FTM.

:rofl: ...does anyone read through any thread before posting? :rolleyes: ...:rofl:

I did. I just wanted to add in. Would you have preferred the :iagree: icon?

Don't worry, I always read your posts, mD. 90% of the time, they're the same thing I'd say, except put in a wittier, less-boring sort of way.

LOLOLOOL :rofl:

and THIS i why i love x5world :D

Not sure why you didn't stick with the RFT. Have them on my 6, no issues. You are aware you don't have any type of spare on that car?? :)

bmw assist = world's greatest spare tire :D

my m3 never came with a spare either: just a "mobility kit" or something which even bmw assist would never use lol