I did a search but couldn't find a generally accepted answer.

If you're running 20" wheels with 30 series tires, what PSI would you set you front and rear tires to?

 

I would say at least 40 to 45 PSI.

 

40 psi sounds about right...

 

dont quote me, but i think they're supposed to be 38psi.

 

i'm running at 38 psi, as recommended by wheel expert rominl

 

there is no standard or must

if you want, even the factory spec of 32/33psi will work just fine on 20s. however, with the lower profile tires, you risk more on damaging your wheels if you hit potholes or so. that's why some might recommend a bit higher psi for protection.

with that said, too high psi will get you over-inflation and premature center wear on the tires. so it's a toss

to me, i put 38-40psi cold (make sure it's at cold) on my 20s. i used to run 44psi and i got center wear and the ride was a lot harsher than i'd like

 

thanks all. This is perfect.

 

I have 35 series tires and I've been told by the dealership, the wheel distributor and my shop to keep them between 33 and 35psi. I'm sure it must be different for 30 series tires.

 

32 psi for a 35 series tire is too low. Most cars that comes with low profile tires from the factory recommands about 40 PSI.

 

Well I've heard 33-35psi from 3 different reputable sources. A tech at Lexus told me this, so did the shop who sold and installed my wheels. The owner/manager there who I know has been in the wheel business for a decade, so I would think he knows what he's talking about. It's a shop that specializes in wheels and has several large locations.

 

Go with the professional advice, I am just a weekend warrior

 

you have no idea how many "professionals" i talk to who actually know less than what i do as a weekend warrior. but like i said, if you are rolling on silky smooth roads like autobahn, put it factory 32psi for sure!

i do learn from experts, but at the same time i make sure i understand the reason behind so i can make my own judgment

and btw, 35 series mean nothing. 245/35/19 and 275/30/19 have the same profile, it wouldn't make any sense to have different pressure between them

 

The suspension design of the car will affact the proper PSI setting as well. The Lexus recommanded PSI for the oem 17" 50 series tires are 32 PSI already. Going down to a 30 series there will be much less sidewall. To compensate for the decrease in sidewall height, the PSI should be higher assuming the suspension and tire width is the same.

 

folks, the only reason for having higher psi in your tires is to avoid bending your expensive wheels when you inadvertently hit a pothole. if you don't care about potential wheel damage, by all means go with the regular psi that the "professionals" recommend. as for me, i'm gonna go with what i think is best.

 

that could be the case. i thought about it too. but between 17s and 18s i think the recommended factory psi are the same?

on the is-f (19s) they do recommend higher psi though