what air press. are you guys runnin in your bias ply big tires???

[01maroonz71]

im running 40tsl's and im wondering what would give me best tread life for the street.. i do about 75%street driving and will air down when i go offroad. what are ya'll runnin????

 

[onetonbb74]

i leave them at 15 psi all the time, and if i have to drive far (lots of freeway) then there at 25psi. I run a 10" wide rim and have the 15/39.5/15 tsl's, they bubble a little so 30 psi is way too much.

 

[dbreid]

I run my 40 TSL bias Ply's at 28-29 psi when I am on pavement. I run them between 11 and 16 when off road, and a little lower if I need. I don't have beadlocks (but they are on 17's) so I am a little paranoid about low pressures.

It is also worth noting that my truck is a K30 with a Big Block, and about 1000 pounds of spares and boxes and tools, etc. Hence the high pressures.

 

[dbreid]

Just to show you where I got that info, here's a quote from the interco website:

Maintain the proper air pressure for your driving and load conditions. Check the air pressure once a month with a GOOD accurate air gauge. Two things support the weight of a vehicle...the volume of air and....the airs pressure. With big tires the large volume of air in the tire will SUPPORT the vehicle but the tire will not be stable...the tire will look OK but when running on the highway at high speed it will wiggle and squirm which the tire is not designed for and it will not deliver near the mileage it could with the proper inflation pressure. This is not important when running off road because you don't have the speed plus the ground is softer than the tire but when you get back on the highway you should bring the pressure back up again to whatever pressure you have determined is best for the loads carried and your driving habits. Big tires will almost always LOOK like they have enough air when actually they may not for highway driving. So don't just kick your tires...check them. If you want to see what we mean try letting the air pressure down to 12 pounds or so...you probably won't be able to notice anything abnormal unless yours is a very heavy truck...but the tire, at 12 PSI is seriously under inflated for highway service.

That is taken from:
http://www.intercotire.com/site39.php

 

[5280k5]

I run my 39.5's at about 12-15 on the street and lower offroad. I originally had them at about 25 psi on the street and found for longer highway drives the two center tread blocks would get pretty hot and the outer lugs were barely warm, uneven heating means uneven wear. These are 15" wide swampers on 9.5-10" wide beadlock wheels.

 

[dbreid]

Yeah. I think it makes a difference how heavy the rig is, too. I always check to make sure my tires are heating up at the outside as well. And I thought I was weird!

I am mostly concerned about sidewall flex, as opposed to tread, though. You are right that overfilling is bad for the center tread, but I have had luck with the higher pressures.

 

[5280k5]

Yeah. I think it makes a difference how heavy the rig is, too. I always check to make sure my tires are heating up at the outside as well. And I thought I was weird!

I am mostly concerned about sidewall flex, as opposed to tread, though. You are right that overfilling is bad for the center tread, but I have had luck with the higher pressures.

Yeah, I hear 'ya. Interco probably wasn't too worried how their tires work at 75 mph either
I figured if the tires were heating evenly across the tread that meant more
contact with the road= more traction & stability, but with the swamper design it probably has less contact than normal tires anyway.

 

[tRustyK5]

I run 23 psi front and 21 psi rear with my 39.5" TSL's when on the street. I drove at those pressures all the way from Vancouver BC to Moab UT (2400 miles return @ 65-70 mph) and back and they never got excessively hot and the truck handled as good as it gets with big bias ply's.

I run a little more up front because of the slightly more weight over the front wheels.

I have 15,000 miles on mine and have about 40% left on em. Wear is even across the tread blocks too.

Rene

 

[Greg72]

17 psi for highway driving based on the proper psi vs. load calculation....

There IS a way to calculate the correct air pressure, a search will find you the thread. I remember answering this in detail about a month ago.

FWIW -> Most people incorrectly assume that large bias-ply tires should have the same 32 - 35psi that they've gotten accustomed to putting in typical radial tires.....it simply ain't so.

 

[Copasetic]

I'm running 25 psi in mine and they are wearing evenly. I've got about 1100 miles on them, so far and are just now starting to wear the tits off. Man, that didn't sound right.

 

[Chaddy]

I run my Maxxis 37's @ 6 psi for offroad and on the road back to the trailer