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What pressures are you guys running with this wheel size/ suspension combination?

My door sill says 33 psi all around. The owner's manual says 30 psi all around, but it doesn't address suspension options. I figure my sill sticker would be specific for my car's set up, but I thought I'd ask you guys as well.

BTW, I just took delivery of my car late Thursday night. Work has been busy, and the weather has been foul around here. I do have garage pics of the car, but my wife hasn't had time to download them from her camera to the computer. I will post them here soon.

Thanks!
 

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I don't think your suspension should affect choice of tire pressure. The tire pressure needs to be in the range that keeps the tire inflated and the ground contact surface maximized. Personally I use the lower end: comfort pressure or 30 psi for my 20 inch wheels (I have pasm)

I didn't read either the sill or the menu to arrive at this. The mfd has a tire pressure page where you pick tire type, size, and comfort and then recommends you a value.
 

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For street tires, personally I've been using either the 30 psi cold (the "comfort" setting) or the 33 psi "regular" pressure.
At the track, depending somewhat on the tire I usually start with @24 - 26 psi cold.
I don't think rim diameter has as much effect on required/recommended tire pressure as overall tire diameter would - but that's usually not one of the specs one makes significant changes to when jumping from 18" to 19" or 20" rims. I'm not sure of the details, but I believe going to a larger diameter tire allows the chassis designers & engineers to increase tire contact patch sizes.
I gather this is generally done by lowering tire pressure.

FWIW, I've got PASM and am switching between 20" (the OEM wheel that came with the car), some legacy 19" fit with snows and 18" track tire/wheels. In switching back and forth, I've had the 20" rims set from time to time at 30 & at other times 33 psi. Don't find either one a compelling "must have" setting - but at 36 (cold) the car is definitely "jouncy" feeling to me.
 

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My door sill says 33 psi all around. The owner's manual says 30 psi all around, but it doesn't address suspension options.
Does it really? I haven't looked at mine, but I doubt the recommended pressures would be different from other Cayman variants. I am running 33 all around and that has worked very well.

 

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Comparing my 2006 Cayman S to a new 981 Cayman, I notice the weight hasn't changed all that much (maybe 3%), the weight distribution hasn't changed, and the tire size hasn't changed (235F, 265R) then why have the tire inflation pressures gone from 32F/37R to 33 all round? Isn't that a significant difference--much greater than any other vehicle parameter? Can someone explain this to me? Appreciated.
 

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Comparing my 2006 Cayman S to a new 981 Cayman, I notice the weight hasn't changed all that much (maybe 3%), the weight distribution hasn't changed, and the tire size hasn't changed (235F, 265R) then why have the tire inflation pressures gone from 32F/37R to 33 all round? Isn't that a significant difference--much greater than any other vehicle parameter? Can someone explain this to me? Appreciated.
Can't other than to point out the "rough" OEM spec diameter for the tires has been increased from @26" on the 987 to 27" for the newer car, e.g 235/40 x19 on the 981 vs 235/35 x19 for the 987.x chassis.

From my admittedly limited an certainly incomplete understanding of tire engineering I think this may be to achieve a larger contact foot print, but I don't know this for a fact, or claim to know all the reasons or analysis behind the science of setting and selecting optimal tire sizes.

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Comparing my 2006 Cayman S to a new 981 Cayman, I notice the weight hasn't changed all that much (maybe 3%), the weight distribution hasn't changed, and the tire size hasn't changed (235F, 265R) then why have the tire inflation pressures gone from 32F/37R to 33 all round? Isn't that a significant difference--much greater than any other vehicle parameter? Can someone explain this to me? Appreciated.
Can't other than to point out the "rough" OEM spec diameter for the tires has been increased from @26" on the 987 to 27" for the newer car, e.g 235/40 x19 on the 981 vs 235/35 x19 for the 987.x chassis.


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Suspension design also has a hand in it.

Ref:
The R was a 987 with a different suspension than all previous iterations and listed a square 31 psi recommended setting.
 

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I have X-73 and 20" wheels. I have run from 30 to 36 in the tires tiring to determine what works best for me. Unless I really plan to push the car hard, I like 33-35. I really do not notice a firm ride than at 30. I am sure it is softer, but I really can not feel much difference.
 
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