Tire PSI??

[bolsen]

I went to autocross this past Saturday, and I adjusted my PSI to 45 in the fronts, and 38 in the rears. I forgot to let the air out of the front, and I drove home (about 40miles) afterwards.

Two things I noticed while on the highway: 1) My car drove amazing. Better handling, smoother ride, more responsive. 2) My gas mileage was vastly increased.

So my questions is this: Is it safe to keep those PSI ratios all the time for a DD?

-bolsen

 

[fastblackmerc]

I went to autocross this past Saturday, and I adjusted my PSI to 45 in the fronts, and 38 in the rears. I forgot to let the air out of the front, and I drove home (about 40miles) afterwards.

Two things I noticed while on the highway: 1) My car drove amazing. Better handling, smoother ride, more responsive. 2) My gas mileage was vastly increased.

So my questions is this: Is it safe to keep those PSI ratios all the time for a DD?

-bolsen

No.

You'll see increased wear & decreased traction.

 

[Bluerauder]

I went to autocross this past Saturday, and I adjusted my PSI to 45 in the fronts, and 38 in the rears.

So my questions is this: Is it safe to keep those PSI ratios all the time for a DD?

-bolsen

I would say NO. As I recall the MAX tire pressure stamped on our sidewalls for our OEM tires is 45 psi. Tire experts on here have stated that you should never inflate to more than 90% of MAX (about 40 psi) to allow for pressure increases as the temperature increases due to driving and braking. Personally, I would not go above that 40 psi recommended pressure on the BFGs. Starting at a 45 psi cold inflation leaves you NO margin of safety as the tires heat up due to road friction and braking. Seems like unnecessary risk for blowout conditions to me.

FORD's recommended pressure is 35 psi all around on the Marauder since 2004. The 2003 MM door panel says 32 psi; but this was changed with the 2004 MM model to improve tire wear. I am running 35 fronts and 38 rear. The recommended pressures are based on a balance of wear, handling, ride, MPG and safety.

I suspect that the reason your Mileage went up is that you were overinflated and your tire contact area was smaller than normal. That will reduce your rolling resistance but eat tires quicker since only a smaller portion of the tire is seeing the road wear (i.e. same forces, same wear ... but spread over a smaller area.) I would bet that your traction on the fronts was decreased considerably too because of the smaller contact area. JMHO.

 

[DOOM]

I run 40psi.

 

[Marauderjack]

I run 45 in front (Khumo 255's) and 30 in the rears (Nitto 295's) and always ran max pressure in the horrible BFG's to get best performance and better wear!!:beer:

Run 40 and see how ya like it......won't hurt a thing!!:shake:

 

[SNOOT]

50PSI cold thats what my own tires say. I run 45PSI cold on DD.. I run less for autocross or drag racing DOC..