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What psi for BFG tires.
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Author:  adamkrz [ Sun Nov 18, 2007 5:05 pm ]
Post subject:  What psi for BFG tires.
Just got a good deal on 5 BFG AT's t/a, 245/75/16 they are the ko type,What does it require for air pressure? On the side it says 80psi cold and the guy who mounted them for me said I should run at least 50 psi or more because of the e- rating.I'm not familiar with these heavy duty type tires and never ran more than 34 psi for all my other tires..
Author:  KY Liberty [ Sun Nov 18, 2007 5:21 pm ]
Post subject: 
I just went with some Silent Armor 245/75R16 load range c tires that say 50 psi on the side. The 33 psi on the door label was definately too low. What I did was divide the 33 psi recommendation by the 44 psi maximum for the tire and got 0.75. I multiplied that by the 50 psi for the new tires and came up with 37.5 psi. We put 37 psi in them and it seems about perfect. I don't know if this method is the correct way to do it, but it worked for me. Hopefully some people with load range e tires will chime in since the weight handling differences are more significant going to the e range tires.
Author:  KJ Taz [ Sun Nov 18, 2007 5:23 pm ]
Post subject: 
My Jeep came with the same size and load rating and it only called for 33psi. Its slighty lighter, so yours should probably be slight higher in the PSI range, but not much Heck 40 would be far to much. Probably around 34 to 35. A good way to tell how much air to run in your tires is the chalk test. You put a chalk line across the tire and slowly lower the pressure till it starts wear all the chalk, that way you know the tire is making full contact with the road.
Author:  tommudd [ Sun Nov 18, 2007 5:33 pm ]
Post subject: 
Chalk test is great but seems like most are in the 35/40 range. Depends on the tire as well, but that will get you in the ball park!

Tom
Author:  Jeepjeepster [ Sun Nov 18, 2007 5:56 pm ]
Post subject: 
33-36 for the liberty.

It doesnt have as much to do with the type of tires as it does the weight on the tire.
Author:  jason thompson [ Sun Nov 18, 2007 6:22 pm ]
Post subject: 
To get in the ball park you can just do some quick math and adjust for ride quality
for example
80 psi is for MAX load wich is around 3000# per tire
and you have 4 tires so that would be 12,000#
if your KJ weighs 4000# then you need about 1/3 the tire you have so you need to run abbout 1/3 the MAX psi
or 80/3
or 27 psi
start here and then do the chalk test
you will probably end up at ~32psi
that is where we are with our MTR's ,same LR as the BFG's
Author:  adamkrz [ Sun Nov 18, 2007 6:45 pm ]
Post subject: 
Hey Thanks everyone - Very good answers -going outside to air down- One more thing-- When I checked tirerack for info on the tire it says max rim width to be 7.5 in. , I hope the crager soft 8 will be alright since I got the 8" rim..
Author:  JeepBeat [ Sun Nov 18, 2007 7:06 pm ]
Post subject: 
I have regular Uniroyal Laredo radials on my Jeep. I think the max pressure is 44psi. What would be the norm to run them? I always ran my trucks around 30-35, but the Jeep's tires are all at 25psi. I hadn't checked the pressure since I got it used a few months back. Should it not be higher than 25psi for proper wear and gas mileage. Sorry to step outside the topic.
Author:  Jeepjeepster [ Sun Nov 18, 2007 7:11 pm ]
Post subject: 
JeepBeat wrote:
I have regular Uniroyal Laredo radials on my Jeep. I think the max pressure is 44psi. What would be the norm to run them? I always ran my trucks around 30-35, but the Jeep's tires are all at 25psi. I hadn't checked the pressure since I got it used a few months back. Should it not be higher than 25psi for proper wear and gas mileage. Sorry to step outside the topic.


33-36 for the liberty.

I run 245/70/16 on 8" wide rims.
Author:  JJsTJ [ Sun Nov 18, 2007 7:36 pm ]
Post subject: 
40 psi if you want to help your mileage a bit. That is what I have run in both GY MT/R's and BFG AT's. Anything less than that pressure and I notice fewer miles per tank.
Author:  Guest [ Sun Nov 18, 2007 8:05 pm ]
Post subject: 
jason thompson wrote:
To get in the ball park you can just do some quick math and adjust for ride quality
for example
80 psi is for MAX load wich is around 3000# per tire
and you have 4 tires so that would be 12,000#
if your KJ weighs 4000# then you need about 1/3 the tire you have so you need to run abbout 1/3 the MAX psi
or 80/3
or 27 psi
start here and then do the chalk test
you will probably end up at ~32psi
that is where we are with our MTR's ,same LR as the BFG's

.
You're about dead-on for the 10 plies on my '02. I've been aiming for 30, but i keep it a couple pounds high since it's gonna do nothin but get colder.

When in doubt, look at the sticker on the door jamb of your vehicle. 33 psi is what the Jeep says. if you don't know, keep it there. NEVER go by the MAX PRESSURE on the tire. all you'll do is wear out the center of the tire, reduce your contact patch, and make your rig ride like a log truck.
Author:  riptricket [ Mon Nov 19, 2007 12:48 am ]
Post subject: 
i got the bfg 235 70r 16 and i run a constant 33psi... i check them almost everytime before i make a journey of more than 30 miles.. which is almost everyday if i go to the g/f's house.
Author:  Dutchy [ Mon Nov 19, 2007 6:07 am ]
Post subject: 
BFG at's 235/70/16 33 psi front 32,5 psi rear, more and handling will suffer especially in the wet, less and the mpg goes down hill.
I have run BFG's on my KJ for 50.000 Miles now and they wear quite even with 33psi (as long as I keep my idiot dealer from doing a ball joint recall without re- aligning)
50 or more psi can mean a blow out as pressure gets much higher when your tyres heat up while driving and it will also shake your KJ to bits as the ride will be bone hard and off road you will loose most of the grip.
Author:  Jeep Dawg [ Mon Nov 19, 2007 11:01 am ]
Post subject: 
With my BFG AT KO I set them in the winter at 30 PSI and in summer 40 PSI. 4Wheeling, I air down to about 25 PSI

I have about 70K on my set of BFG's and they still look new about 80% left on it.
I rotate them at EVERY oil change.

I always had this style of tire and they never let me down as long as I kept up on the maint on them.
Author:  dog_party [ Mon Nov 19, 2007 1:05 pm ]
Post subject: 
I have BFG A/Ts and I run 40psi in the front and 38psi in the rear. It should be noted that I have the diesel motor, which is substantially heavier than the gasser motor. 40/38 rides great and is wearing perfectly on my truck.

Off-road, I'm at 18psi or lower.
Author:  jason thompson [ Mon Nov 19, 2007 6:24 pm ]
Post subject: 
dog_party wrote:


Off-road, I'm at 18psi or lower.




10 PLY or 8?
if you have the 10 or E range try going to 15-16
does wanders for the MTR's
and the Super Swampers on the TJ 14psi
but only if you have OBA
dont want to hit the road that low
Author:  JeepBeat [ Mon Nov 19, 2007 8:39 pm ]
Post subject: 
In my case with Uniroyal Laredo's, I am too low at 25psi for regular driving. I am going to pump them to 32psi or so. Thanks guys!! Also putting my winter tires on tomorrow, so will make sure they are the proper pressure too.
Author:  jnoden [ Thu Feb 07, 2008 11:14 am ]
Post subject: 
you guys may be right but it seems that 35psi in my BFG KO's is too low for such a thick walled tire. Its says 80psi on side wall and while I understand that the Lib is no heavy enough to justif it, I bumped min up to 50 PSI and the shaking and road noise disappeared. It was just a way better ride.
Author:  tommudd [ Thu Feb 07, 2008 1:15 pm ]
Post subject: 
way better ride maybe but will wear out the centers sooner
Author:  sleeve84028 [ Thu Feb 07, 2008 1:43 pm ]
Post subject: 
Chalk test that tire at 50PSI... Just to see if you have a decent contact patch


I run 39PSI on all 4 corners of my FireStone Destination's...
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