Pressure
Thread Starter
3rd Gear Member
Joined: May 2015
Posts: 578
From: Ohio
Pressure
Just got this set up from AM and wondering what tire pressure would be best to run on. Strictly street driving here, not track. Thanks in advance for your replies.
http://www.americanmuscle.com/blackb...invo-stag.html
http://www.americanmuscle.com/blackb...invo-stag.html
Thread Starter
3rd Gear Member
Joined: May 2015
Posts: 578
From: Ohio
6th Gear Member
Joined: Feb 2007
Posts: 7,635
From: state of confusion
When changing tire sizes, it's not as simple as that. There are tables that can be used to determine what the new tires should be aired up to, based on load carrying capacity (which you should maintain, or at least maintain enough for the way your car gets loaded).
It's a "Load Index" thing, and it gets a bit complicated from there. At 32 psi, matching a 99SL tire in XL needs the number to be 103, or you may be able to run a 100XL tire at a little more than 32 psi to get the required load capacity.
If you post or PM the full designation of the tires your car came with and the door sticker pressures, and the full designation of the new tires I will give you the correct load-based inflation pressures that you need to at least start with.
I'm quite sure that the correct front and rear pressures will not only be different from the door sticker number, but they will be different from each other as well.
Beyond that, you can use small adjustments in tire pressure to change the way the car feels as you enter a corner. Adding a couple of psi in the front tires only can make the car feel a little more nimble.
Norm
It's a "Load Index" thing, and it gets a bit complicated from there. At 32 psi, matching a 99SL tire in XL needs the number to be 103, or you may be able to run a 100XL tire at a little more than 32 psi to get the required load capacity.
If you post or PM the full designation of the tires your car came with and the door sticker pressures, and the full designation of the new tires I will give you the correct load-based inflation pressures that you need to at least start with.
I'm quite sure that the correct front and rear pressures will not only be different from the door sticker number, but they will be different from each other as well.
Beyond that, you can use small adjustments in tire pressure to change the way the car feels as you enter a corner. Adding a couple of psi in the front tires only can make the car feel a little more nimble.
Norm
4th Gear Member
Joined: Mar 2012
Posts: 1,044
From: Texas
^ Is this guy great or what? Norm will help, & knows a lot about cars in general. I want to research this myself as I replaced my stock 215/65/17 {98-T} to 275/40/18's squared with Bridgestone RE 760 Sports. Thanks Norm, your great!
6th Gear Member
Joined: Feb 2007
Posts: 7,635
From: state of confusion
Going from 98T at 32 psi to 99W actually means you could drop down to 31 psi because the 99 has greater load capacity at any given inflation pressure. The actual load requirement is for only 1488 lbs, not the maximum 1653 lbs that's embossed on the tire sidewalls.
I'd be strongly inclined to run 34 up front with 31 in the rear to get slightly more responsive handling.
Norm
I'd be strongly inclined to run 34 up front with 31 in the rear to get slightly more responsive handling.
Norm
4th Gear Member
Joined: Mar 2012
Posts: 1,044
From: Texas
I told you Norm's smart, he'll get back to you. Norm when we track these tires, shouldn't we lower the tire pressure at the start of the race to compensate for the friction and warm up of the tires as the race goes on? Or, how many laps at normal pressure till they experience a problem with over inflation?