Tire PSI

[Barry Nave]

Those who have 1-ton duels.
Am looking to see what most think is the ideal tire psi.
Tire size, 235 85 16. Max psi is 80. Load rated E.
This fells to hard and the rears run hard on just center tread.
At 70 psi the contack area of rubber are more flat to the road, still not full rubber patch to road. This fells much better on ride.
I do run the front at 62psi cold.
Having two at the rear,I could run less or the same as the front.
This tire size with truck,tool box and tools, I still have 5/8" in between tires @ 8,200 lbs.
If tires run high on center then I should lower tire psi?

[Dvldog 8793]

Howdy
I have a single wheel 3500 long box crew cab. I run 265 75-16s load range E. I normally run 60psi all the way around. When I haul a large load I jack the back tires up to 70 psi. I think the psi that you run is dependant on the load. If you are running empty then maybe adjust the psi for ride comfort/mileage. Running w/ a heavy load then max it out. Hope this helps!
L8r
Conley

[Billman]

To me, 5/8" doesn't sound like enough clearance.

Run 'em at 80...

[JohnC]

Take your best guess estimate of the weight each tire has to carry. divide that by the maximum weight rating of the tire (in dual configuration). Multiply the maximum inflation pressure by the previous result. This will get you into the right ballpark. Then, drive it for a couple thousand miles. if the tires wear more in the center than the edges, go down a couple lbs. If the wear more on the edges, go up.

For example, say you estimate your rear axle load at 8000 lbs. You have 4 rear tires rated 3000 lbs load at 80 psi. Your load is 2000 lbs per tire. Divide 2000 by 3000 and get 0.67 Multiply this by 80 to get a starting pressure of 54 psi.

YMMV

[Hansh]

I run 235/85R16 load range E, 60 - 65 psi in front and same in rear unloaded, 70 psi light load, and 80 if heavy.

[ 08-10-2005, 11:49 AM: Message edited by: HH ]

[vernj4]

Just changed from 225/75R-16 to 750-16 tires all around. The spacing is the same as the original tires and the height is the same as the 235/85R-16 tires. There was no cost penalty for the 750-16 tires.

[Barry Nave]

John C
Thanks. I weighed the truck this morning.
Rear is 4060Lbs. Total is 7600Lbs.
Would I take the rear weight only? by your caculation
This would make rear tire PSI low? yet the sticker(driver jam) has.
Stock tire size-LT 225/75R 16D
GAWR Front 3800# 50psi.
GAWR Rear 7500# 55psi.

Truck at rear 4060#
Front 3540#
This is the weight I travel at interstate speeds,70-75. I can at any given point add 600# to the rear.
Good used rubber, Have blowen Two tires at rear.
Now have a full set of new rubber.
There for I may be running to much air#. Add speed and heat= + air psi.
Bottom line, need to fine air that will match- tire wear and life.
New rubber is not the best money can buy but should last with out blow outs and wear longer than 20K
Thanks guys for any input ;)

[Billman]

Low Tire Pressure + Heavy Weight = Tire Heat.

[Barry Nave]

Bill Man.
True, though low psi with heat will raise tire psi,now we're talking to low tire psi.
Tire recamendations are at cold PSI.
I've blown two good tires at 70+75,road temps at 125* (inferred gun). Running 70#in each tire.
So what psi did the tire increase? With heat?
My duels with the SS ring I have ,I can not CK tire PSI with out R&R the wheels.
John C is on track. I'm thinking of running lower lbs for Interstate speed.

I did(my wife did) the math with John C. Calculation. Seem's low, yet it makes sense ;)
By the way I also know how NASCAR do the tires. :D Had to through that in :D
I'm may be taking this simple tire psi to a science,Though money is also a issue.

Correct me ;)

[Kidd]

I have a 98 K3500 dually, running 215/85R-16 tires. Find the best pressure is 65 psi front, 55 rear. Also happens to be factory recommendation. The issue here is to maintain the same loaded radius front and rear, since it is a 4X4. Tire wear is even all around but I do rotate once a year.

K.D.

[Barry Nave]

HH
With your tire size. How close do the center rear spacing come?
The tire size I'm running fills the wheel well in good.
Is there any difference in over all height?
Compared to the 225/85/16