So, I bought a set of new Kumho's. Always been very happy with them. Had them put on about a month ago. Two days ago I wanted to check the tire pressure. When I did I was astonished to find out they were about 9 PSI too low on all tires. I guess the installer messed up.

Anyway, I inflated them to the recommended pressure... man, what a difference!! The car feels so much lighter, more nimble and quicker. I never realized how much low tire pressure slows down the car. My buddy said it's basically like driving through sand when pressure is that low.

Anyway, don't make the noob mistake I made not to check tire pressure after you have new shoes installed.

 

It's best if you tell your installer what kind of pressure you want right away.

I prefer 0.1 bar lower than recommended on rear wheels so I let him know everytime and never had that problem.

I had my front tyres inflated more than my rear on my Benz tho. But I felt that something was off.

 

Yup, now I know I guess the fine people at Just Tires didn't bother to look on the door sill.

 

Just out of curiosity, what pressures are you running?

 

What was it? 37 front 44 back? I just did what it said on the door sill.

 

To Marlon 997.. that is way too high... I am thinking 33/36 runs much better, especially if you drive (mostly) on your own.

 

Checked the manual. It states 37-44 for fully loaded. 33-39 for partially loaded. Should I ignore the manual's numbers? I'm confused.

 

No, but adjust them for numbers used in the REAL world, AKA pressures what everybody uses. I am using 33/36 and found that to be the best "all-round' setting yielding the best ride AND the best WEAR pattern on both front and rear. Measured COLD of course.

 

Start with the recommended numbers and adjust to your preference. Keep the front/rear ratios but dropping the pressures around 4 lbs per tire works well for my set up.

 

Great advice all around. Thanks a bunch. I'll try diff pressures and see what rolls best.

Thanks again!

 

I run with 34/37. During track and autocross, I find that my street tires get greasy once the pressures hit anywhere close to 40. Careful when you get service at a dealer though... mine filled the tires back up to 37/44 which I did not notice until I got home. The car felt completely different with those pressures.

 

I've noticed my Kumho's LE's sidewall is a bit soft. Should I inflate them a bit more to compensate for that and put in a bit more air?

 

Some tires look "less inflated" than others. You should work with getting correct pressures.. not with " looks"..

 

"Looks"? I'm not going by looks. I'm going by how the tire feels in sharp turns and it feels like the sidewall is pretty mushy. Hence the question: should I make the tires a bit harder to remedy the soft sidewall feel.

 

I would chalk your tires and test in those turns to see if what you're feeling aligns with how the tires are actually behaving.

Begin by rubbing the chalk on the sidewall of the tire and then move up to the tread blocks found in the shoulder area.

After you’ve chalked all four tires in various places around the tire’s circumference, take the car out for a few practice laps or perform some hard cornering maneuvers in a safe area.

Next, inspect the chalk marks and determine if any pressure changes need to be made. What you’re trying to achieve is to have the chalk rubbed off close to where the tread design ends in the shoulder area of the tire. If all the chalk is rubbed off a tire, add air pressure to the tire. If, on the other hand, most of the chalk is still on the tire, reduce the air pressure in the tire.