Need help on tire pressures

[Xanth]

BFgoodrich engineer related this equation as a good starting point:

 

(Vehicle Weight in lb/100) + 2 psi at heavier end + 2 psi all around if suspension and alignment are stock.

 

Example: Stock 911, 3,000 lb.

(3000/100) = 30 psi

Add 2 psi all around = 32 psi

Add 2 psi to heavy end = 34 psi at rear

With modified suspension, the result is 30 psi front, 32 psi rear.

 

(from: http://www.sportcompactcarweb.com/tech/0208scc_tires/)

 

Thought that was interesting, the weight of my trunk stereo install,mats, gf, me...all makes a difference.

[ONRAMP]

BFgoodrich engineer related this equation as a good starting point:

 

(Vehicle Weight in lb/100) + 2 psi at heavier end + 2 psi all around if suspension and alignment are stock.

 

Example: Stock 911, 3,000 lb.

(3000/100) = 30 psi

Add 2 psi all around = 32 psi

Add 2 psi to heavy end = 34 psi at rear

With modified suspension, the result is 30 psi front, 32 psi rear.

 

So based on roughly 3400 lb LGT (maybe off on that figure?):

(3400/100)=34 psi

+2 in the (heavier) front end

+2 all around for stock alignment and suspension

Comes to 38F/36R, which is exactly where I have mine set!

 

Drove 200+ miles today, as mentioned above. Drove great, ride was less noticably harsh on smoother interstates, held on nicely in passing on two-lane roads, and felt pretty stable up to about 110 mph (following a Ferrari, no less). Will be keeping my pressures here for a while.

[Xanth]

Yeah, following the formula I have mine at 40/38 based on the weight in my trunk. So far so good, nice ride, nice crispness to the steering, peace of mind knowing the rims are better protected against friggin ny potholes.