How do I find out my tyre pressures?

[Kylinski]

And probably a bit less due to the SLK not being as heavy?

 

[television]

And probably a bit less due to the SLK not being as heavy?

Running so low you do stand a good chance of wearing our the sides before the center of the tyre

 

[gizze]

I set the pressures at manufacture recomendation. The ride was so hard it felt like I was back in my MG TF!

Think I'll set mine at 26 front and 28 rear as oppossed to 30 and 33

That's not the brightest idea to be fair, if you under inflate the tyres by 6psi you are in danger of a blowout, the tyre gets hotter and the sidewall can burst.

This is an extreme, but not worth risking.

Also, I had a chart somwhere that BMW supplied for the E46, going from a 15" 195/65 profile tyre, up to the 19" 265/30 profile, and the differences in pressure was quite extreme, 31psi for the 15" and 42psi for the 19" on the rears.

I would never run anything below 29psi, at 25psi I would be worried driving it.

 

[television]

That's not the brightest idea to be fair, if you under inflate the tyres by 6psi you are in danger of a blowout, the tyre gets hotter and the sidewall can burst.

This is an extreme, but not worth risking.

Also, I had a chart somwhere that BMW supplied for the E46, going from a 15" 195/65 profile tyre, up to the 19" 265/30 profile, and the differences in pressure was quite extreme, 31psi for the 15" and 42psi for the 19" on the rears.

I would never run anything below 29psi, at 25psi I would be worried driving it.

Yes that is about the lowest figure usable, my 140 runs on that, but all the others higher

 

[rlw]

Tyre pressure remain the same irrespective of the wheel/tyre combo.

Really? On 911's the pressure can hange quite dramatically between even 16" and 17" wheels, albeit more so on the older models. Once you are into 18"/192 they become the same but the variations are definitely there and significant.

 

[whitenemesis]

Really? On 911's the pressure can hange quite dramatically between even 16" and 17" wheels, albeit more so on the older models. Once you are into 18"/192 they become the same but the variations are definitely there and significant.

My statement was rather a sweeping generalisation but holds true in most applications as it's the axle weight that determines the pressure required.

You are right to point out there are instances were this may no longer be 100% correct but then (I'm guessing) this would be highlighted by the manufacturer?

Running extreme (as in outside the manufacturer's spec) rim/tyre combos is always going to be something of a trial and (hopefully not) error exercise. Keeping within the range stipulated in the handbook or on the fuel filler flap is a good starting point though. Keep checking wear and assessing ride/handling is the order of the day though. Erring on the high side is prudent with very low profile set-ups to help avoid snake-bite punctures.