Pontiac GTO Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter · #1 ·
I've had my car for about 1 1/2 months. It rides a little rough and so I checked the tire pressure. The tires were 36psi. I have the original 17's. The manual says the tire pressure should be 30 front and back unless I have a very large cargo. Thus, I compromised and just put them at 32. (haven't driven it yet to see if any difference). What are your thoughts about tire pressure for the original 17 tires? Thanks for any help.
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #3 ·
This is true. Inside the car it does say 35 front and back for the 17's.

What I'm wondering is this: The manual gives you a choice between 30 and 35 psi.
If "occupant and cargo weight 470 pounds or less" put in 30 psi. If "occupant and cargo weighs up to 740 pounds" put in 35 psi.

Do you think that is what the inside of the car is stating - assuming there will be a larger occupant and cargo? Sounds like 33 would be a compromise. Any more thoughts?
 

·
Registered
Joined
·
113 Posts
You should never set your tires below what the door says, unless aftermarket wheels and tires are used. The door plackard is always right, and manuals have been known to be wrong in all brands of cars, due to companies using the same manuals for several cars in their lineup with only different covers.

The reason is that the tires are tested at a certain speed (see below)for a period of 1 hour at the set psi at a specified load. When the tire is tested with less than optimal psi, it will not last nearly as long or the high speed. AKA crash and burn.

speed rating speed
H 130mph
v 149mph
w 168mph
y 186mph W,Y,(Y) are all under the Z rating
(y) 186mph and up:rofl:

There are several other speed ratings, but I just put down the ones related to the new GTO, I believe stock is a v rated tire.
You can set your psi higher to carry more weight, but do not set above 40 or 45, whichever is max psi. +1psi=+40lbs approximately.

Sorry for going technical again, but I hope it gives you guys better understanding:D
 

·
Registered
Joined
·
18 Posts
Discussion Starter · #7 ·
Thanks for the advice, I really appreciate it. Also, the tire itself states not to go over 40 psi. So, I will set the tires at 35 as the specifications in the car state rather than the manual. Thanks again.
 
1 - 11 of 11 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top