my recently purchased 997 came with 20 inchers. Any recommendations for most ideal tire pressures to run (street use)?

the fronts are 245/30's and rears are 305/25's

 

I run 33lbs. in the front & 36lbs. in the rear cold.

 

that's lower than I thought but I guess it makes sense... lower volume, lower pressure. But now that I think about it, my bikes are the opposite - my road bike tires are lower volume but run much higher pressure than my bigger mountain bike tires... hmmm, it's been a while since physics class!

How about for auto-x or track days? I won't get to do any until spring but I'm curious.

 

That sounds super low, usually people run higher pressures for larger wheels. I also recently bought a c2s with 20s and I think the pressures were at more like 37/41 - I'll double check my service records tomorrow.

 

You are right SecretAsianMan, I meant to state 33lbs.front & 36lbs.in the rear, I changed my original post.

 

Shouldn't you be running higher pressures to protect the rims? With those short sidewalls, I'd think that even a mild hit on a pot hole will cause the tires to bottom out. I don't run 20's and have no experience. Just thinking out loud... dave

 

I completely agree with Dasams. Running 20" instead of 19" should not lead to a decrease in pressure. On the other hand, you should run at least the pressure indicated on the door sill (by Porsche engineers) or even slightly more to protect your rims. 36 PSI in the rear is not enough, in my opinion.

Yves

 

I have the same setup on 20's and run 36 front, 42 rears with no issues yet. Hope this helps.

 

36/40 for me. Just feels right with those numbers.

 

34 and 42.

 

When it comes to tire pressures, there's a balance between rim protection and grip. More air, more rim protection but less grip. The tire needs to flex to generate heat which is where grip comes from. Try Porsche's recommended tire pressures, -2 PSI.