quick tyre pressure question.

[siwil1]

Hi Guys, I have finally put some 17'' wheels on the car (9-3 cab)and on returning from the wheel place found the tyre pressures to be all over the place (no surprise there).

What pressures should I have front and back? the tyre are toyo 215/40/17

thanks in advance

Simon

[Mr Beckerman]

I would start with factory specified pressures and adjust from there. Remember, it's pressure of air, not volume.

Kelvin

[siwil1]

Mr Beckerman said:

I would start with factory specified pressures and adjust from there. Remember, it's pressure of air, not volume. Kelvin

Hi,

Does anyone know the factory pressures for 17" wheels my handbook only states 15&16"

thanks

[Prof Beard]

siwil1 said:

Mr Beckerman said: I would start with factory specified pressures and adjust from there. Remember, it's pressure of air, not volume. Kelvin Hi, Does anyone know the factory pressures for 17" wheels my handbook only states 15&16" thanks

The manual for my '02 ("old 9-3" Aero HOT convertible has 33psi for 215/17 45. (These are the tyres fitted to the 17" wheels that came new). Is yours a "new" shape one, if not 40 profiles are not the right profile for 17" wheels I suspect?

[siwil1]

mmmm. thats strange. Maybe the later cars had a higher profile as I shopped around a bit before buying and also looked up some conversion charts and they all said 215/40/17 would be an equivalent to the 195/60/15 which were already on there,unless these were wrong.

on another note not only have they transformed the car visually the handling/ride have been greatly improved. Driving at motorway speeds last night in the rain the car felt "planted" and a lot smoother than on the prev rims. The Toyo proxes obviously help!

[Prof Beard]

My owner's manual lists the various wheel/tyre sizes/pressures used on 9-3s (mine's an "old shape" 02 model) - when I go out to the car I'll have a look at the 15" information and post back...

[Prof Beard]

Prof Beard said:

My owner's manual lists the various wheel/tyre sizes/pressures used on 9-3s (mine's an "old shape" 02 model) - when I go out to the car I'll have a look at the 15" information and post back...

My 9-3 owners manual lists 205/50 for supplied 16" rims...

[siwil1]

Hi Prof,

Thanks for the reply, Ive dug my book out and it says the same so the tyres are correct ie 40 profile for 17" wheel.

conversion as follows

195/60/15 = 205/50/16 =215/40/17

and pressures at 2.2bar

thanks again

Simon

[Prof Beard]

siwil1 said:

Hi Prof, Thanks for the reply, Ive dug my book out and it says the same so the tyres are correct ie 40 profile for 17" wheel. conversion as follows 195/60/15 = 205/50/16 =215/40/17 and pressures at 2.2bar thanks again Simon

Thats really strange - my owners book (02 old shape) gives tyre sizes as:

195/60/R15
205/50/R16
215/45/ZR17 (Note 45 and not 40)

and pressures at 2.2bar for 15" and 2.3 for 16" and 17"

I have no idea why! The latter are what are fitted to my Aero - I'm sure it's not a typo because it appears in more than one place in the manual.

Ho hum, guess that's Saab for you...

>> Edited by Prof Beard on Wednesday 15th February 16:19

[siwil1]

Prof Beard said:

siwil1 said: Hi Prof, Thanks for the reply, Ive dug my book out and it says the same so the tyres are correct ie 40 profile for 17" wheel. conversion as follows 195/60/15 = 205/50/16 =215/40/17 and pressures at 2.2bar thanks again Simon Thats really strange - my owners book (02 old shape) gives tyre sizes as: 195/60/R15 205/50/R16 215/45/ZR17 (Note 45 and not 40) and pressures at 2.2bar for 15" and 2.3 for 16" and 17" I have no idea why! The latter are what are fitted to my Aero - I'm sure it's not a typo because it appears in more than one place in the manual. Ho hum, guess that's Saab for you... >> Edited by Prof Beard on Wednesday 15th February 16:19

Mine is a 99 T so maybe they changed. Thats why we love em!

[Prof Beard]

I did wonder if it was because by 02 the only 9-3 cars shipped with 17" wheels as standard were the Aeros like mine, which have a lower ground clearance I think? (Hence the 45 rather than 40? That would imply that such cars had instruments calibrated to match I guess?)

[LongQ]

Prof Beard said:

I did wonder if it was because by 02 the only 9-3 cars shipped with 17" wheels as standard were the Aeros like mine, which have a lower ground clearance I think? (Hence the 45 rather than 40? That would imply that such cars had instruments calibrated to match I guess?)

Perhaps it's just for a bit more pliancy in the sidewall to counter the harder and lower suspension? It would presumably resolve the ground clearance too but any big difference would negate the purpose of lowering in the first place! Or have I missed something? I assume the calibration would be electronic, so a swift re-program should do it?