Correct Tire Pressures (cold)
Thread Starter
Instructor
Joined: Nov 2007
Posts: 216
Likes: 0
From: Willie Nelson Country TX
Correct Tire Pressures (cold)
Very minor question but can't google the answer. I am running 19" CCW 505As on all 4. Front are 10" & rear are 11". I have Nitto Invos all around - 305/30 ZR19 rear & 285/30 ZR19 front. Love the tires and the rears kept my spedo accurate - low road noise - nice ride but have never known exactly how much to inflate to get the most tread on the road and even wear.
Anyone been there - done that?
Thanks
Anyone been there - done that?
Thanks
Pro
Joined: Oct 2002
Posts: 590
Likes: 0
From: Saratoga CA
What you are really looking for is a cold tire pressure that gives you the proper contact patch when the tires are hot. The way to determine this (if you really want to get it right) is to first get the tires hot. Once they are hot use a big piece of chalk and draw a thick line across the tread on all four tires, then drive the car in a straight line a bit and check to see if the chalk line is wearing off evenly across the tread. If it's weaing evenly then the tire has the proper pressure and the contact patch is maximized. If it is wearing off more in the middle than on the inside and outside the tire is over inflated so reduce its pressure by 1/2 to 1 pound. If the line is wearing more on the outside and inside of the tire than in the middle then it's underinflated so increase the tire's pressure by 1/2 to 1 pound (if it wears in any other manner your wheels are probably out of alignment). If you have to adjust for over or under inflation draw a new line on the tire and repeat the preocesss until the line wears evenly. Once you get all four tires properly inflated while hot let them cool then measure what the cold pressure is for each of your tires. Don't be surprised if it's not the same for all the tires.
