Tire Pressure Question

[BarryD]

I tried 70 psi in the back tires today to see what the difference was and thought the ride was a bit smoother. Will I hurt the tires running 70 psi with nothing in the back?

Tires are the stock AT's from GM.

Thanks
Barry

[DmaxMaverick]

If empty, you can go down to 35 PSI, or less. The key is to calculate the actual weight on the axle and divide it into the capacity of the tires (6084#'s) This will, generally, give the best ride, traction and wear.

For example, if you have 50% of the capacity (about 3000 #'s), you could theoretically run at about 40 PSI (50% of 80 PSI). This will work in most cases. The listed pressure of 80 PSI is assuming that the tire is loaded to capacity. Less load requires less pressure. The tread wear will tell the whole story.

[oyazi]

70 is too much. I ran 60 w/a 4k# trailer for 4kmiles and the center was worn more than the edges ~ this w/stock fireflops

[LA DMAX]

Just like oyazi said, you will wear the center and not edge of the contact surface of the tire. Your tire life will decrease and when you rotate, it won't wear off that slight feathering you get from the fronts. If unloaded I run the rears at 44psi, seems to get the whole patch on the ground. The fronts are at 55psi. Following DmaxMaverick's advice on psi and load will keep you on track.

On edit: You'll enjoy the ride alot more if you get down from 70psi.

LA DMAX

[BarryD]

I did lower the pressure down to 55 in the back tires and noticed a big difference. I have been running with 55 psi in the back now for a few weeks. Feels good I can't find the lowest Tire pressure written anywhere on the truck or manual. Can someone point me in the right direction? :confused:

I see the MAX pressures on the door sticker. I would guess 45 psi sounds about right considering the fronts (55psi) are supporting a motor and the back is just supporting a Bed Liner and a Tonneau Cover most of the time.

[James S]

Hey Barryd

Any milage difference with the different pressures? What milage are you getting on the highway and in town?

James

[BarryD]

I have been running with 50 PSI and the ride is good. I really don't keep close track of fuel mileage. Was 22 MPG @ 75 MPH the other day.

I will be towing our trailer around soon. That is were I am more interested in the mileage. The trailer weights 7000 lbs wet. I am not expecting the truck is going to have to work too hard.

I want to see how it performs with an ATV in the back, canoe strapped to roof and 4 "full size" guys and their gear plus the trailer on the back.

[Bill Knieper]

When I put a 600 pound ATV in the back, milage drops about 1 and 1/2 MPG. I do not think it is as much a weight issue as it messes up the trucks aero dynamics.