GenVibe - Community for Pontiac Vibe Enthusiasts

Hi, I received my four 225/40ZR-18 Kumho Ecsta ASX on 18" rims a few months ago, and they were shipped to me at 40psi. After reading some past posts, I dropped the pressure to the recommended 'factory' setting of 32psi.Now when leaving certain parking lots and hitting some pot-holes, even at extremely slow speed I can hear/feel the front rim(s) bottoming out (not the springs, thats a completely different feel). It's not a good feeling, and I always run out in a panic thinking my rim may be bent.What do most Viber's set the PSI to on 18" rims and 225/40-18 tires?I am seriously considering upping at least the fronts to 36 or 38psi.

same tires on mine in every way, at 40psi they were very smooth on turning and any bump i hit was as soft as i needed, but i have a stronger suspension. at 30psi when i turn if i let go of the wheel to let it center itself it does it way to fast and it feels horrible. at 35+ i liked the way felt all around. as far as wear, it was wearing more in the center, but i also had a hole in one and every few days the pressure would drop by 15psi less so i know that really messed up what the wearing should be like, i kept it overall between 38-42 so wearing should be quite normal at 35-37

Cool, thanks for the input, because at 32psi they REALLY don't feel right, hitting a speed bump at any more than 2mph would cause the rim to hit...NOT GOOD!Do you recommend bumping up to 38psi then? Both the front and back tires?Any other input from other vibers?

36-38 psi should be fine. my only suggestion is to watch your tire wear, if you find after a 1000 miles that the centers are starting to wear faster than the outsides you might be running too much pressure in them and need to bump it down to 34-35. (obviously if your camber is off (lowered car) or if you are doing lots of high speed cornering, the outer edges of the tire will show more wear) you just want the treadwear depth to be pretty consistant on the middle of the tire as the rest of the tire.

hes basically saying if its wearing in the center cause its to high, hit turns harder to balance it out...

Quote, originally posted by manicdan »hes basically saying if its wearing in the center cause its to high, hit turns harder to balance it out...Exactly! (or hit an extra pot hole to loose some air pressure in that tire)

I run mine at 40PSI. What does the side wall say as max pressure?