this my be a dumb question but, my wifes scion tc aftermarket 18" tires dont have a tire pressure rating on the sidewall so, i inflated them to a little lower than factory specs. which is 32psi for the front and 29 for the back. where could i find this info? i tried the kumho website but found nothing. or is it just trial and error and pay attention to the tread wear. thanks in advance.

 

The sidewall is only going to show you a MAX pressure rating. This is not what you should run in your tires.

Go by what the door label tells you.

 

Drivers side door jam will tell you what to run.

 

thats what i did but, the tire and wheel combo is larger and has a different tire size.

 

Most vehicles run about the same pressure.

 

doesnt matter any more the dealership failed to tell me my camber was all jacked up and now my tires are dun. i just took it in for its 15000 mile service and 2000 miles later the whole inside of both front tires are showing wire. this is the reason why i do all of my own maintenance.....this is crap. i figured i would use my three free oil changes and service. never again. i hope others can learn from this as well.

 

You want to run your wifes tires at 35 psi. You do not want to run the tires at the max psi rating that is located on the side because they will unevenly wear out on the inside of the tire. Unless you have a HD truck/Duelly, you want to run all tire and wheel combos at 35 psi (this goes for 16 inch rims and tires all the way to 28 inch rims/tires).

 

BTW Driver side door jam is for the factory wheel/tire combo only. It also gives the specifications for aligning the car. After you change to bigger wheels and tires those numbers are meaningless.