What tire pressure are folks running on the street with BFG KM 33x10.50s on stock rims?
What tire pressure you running on-road? BFG KM 33x10.50
- Thread starter daveIT
- Start date
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my km2's are tagged to run 50 psi cold i usually run about 40
40 Psi.
On 7" rims, 32psi. If loaded up for a trip 35psi.
NCFJ
Supporting Vendor
This subject has come up several times over the past few years and like most subjects here the answers vary a great deal. I was taught this procedure years ago by an engineer that worked in the tire industry and also told how to do it by several others involved in both 4X4 and street rods including people at BFG.
It is called "Chalking"
Get yourself a piece of chalk, kid's sidewalk chalk works well.
Go to a nice flat and level parking lot.
Rub the chalk across the tread blocks of the tire covering them complete from side to side. Do it on both front and rear tires.
Drive the rig 100' or so across the parking lot and check the pattern of the chalk left on the tire.
Worn completely off in the center and scuffer toward the edges-too much pressure
Worn completely on the edges and scuffed in the center- not enough pressure.
Repeat and adjust pressure untill all the chalk is worn off the tire even.
I run 285/70/17 BFG KM2s and 43lbs cold is right on the mark.
It is called "Chalking"
Get yourself a piece of chalk, kid's sidewalk chalk works well.
Go to a nice flat and level parking lot.
Rub the chalk across the tread blocks of the tire covering them complete from side to side. Do it on both front and rear tires.
Drive the rig 100' or so across the parking lot and check the pattern of the chalk left on the tire.
Worn completely off in the center and scuffer toward the edges-too much pressure
Worn completely on the edges and scuffed in the center- not enough pressure.
Repeat and adjust pressure untill all the chalk is worn off the tire even.
I run 285/70/17 BFG KM2s and 43lbs cold is right on the mark.
I run my 33x10.5 BFG ATs on stock rims at 32, seem to wear pretty good.
- Thread starter
- #8
Somewhere between 32 and 40...thanks!
38psi around town, down to 25 on washboard and off road. That's in combination with OME Med/Heavy and the firmest ome shocks.
I have stock rims, they are too narrow, the 10.5s are wearing on the edges due to the narrow rims.
HD
I have stock rims, they are too narrow, the 10.5s are wearing on the edges due to the narrow rims.
HD
NCFJ
Supporting Vendor
Or under inflation
The larger the tire the less pressure is required. I run my 35"s at 30 PSI max, less when off road. If its an "expedition" with many miles of dirt roads and the ever present rocks, I drop them down to 20 which smooths things out substantially while still having enough pressure to get down the highway to where I can air back up. I'll get off my lazy butt and convert my AC compressor into an air compressor one of these days.
I run somewhere between 30-40 psi depending how my back is feeling. 
Seriously...
On a highway trip with relatively smooth roads I'll run a little higher pressure for the slight mileage gain.
Otherwise, closer to 32-35 range.
Seriously...
On a highway trip with relatively smooth roads I'll run a little higher pressure for the slight mileage gain.
Otherwise, closer to 32-35 range.
- Thread starter
- #14
They were in mid-20s...pumped them up to 35 and I wasn't sure I could fit in my garage anymore! It made it though...haha. Does ride a lot rougher...may go down a little...
I run 38 psi on my 33x10.5 BFG A/T's on 8 inch wide wheels.
Been getting great wear.
Been getting great wear.
Just tried pumping mine up from 23 to 38 today and wow was it rough! Inner city roads are rough here in Minneapolis. My shocks are also shot/crap(Monroe from po probably 10 years old).
I run 32 front, 35 rear. Chalk test is best, no question...but I haven't done that yet. In the meantime, my logic is that the larger tire needs lower psi than stock...except that I've added a bunch of weight...so, ya, I have a wild-ass guess with a little bit of thought added to it...
33x10.5 KM2's on stock 15x7. Was at 40psi but dropped to 32psi four days ago to find a huge improvement in ride.
Always recommend chalk.
Just make sure to drive it in a straight line while doing this.
Have always gotten good ride / wear with doing this. Been doing this for 20 plus years.
Just make sure to drive it in a straight line while doing this.
Have always gotten good ride / wear with doing this. Been doing this for 20 plus years.
I roll at 32 psi, unless I am leaving town then I put it to 38psi
