I've done a fairly broad search, but have come up empty handed - so to confuse matters even more, I'd like to get some opinions in writing. Airing down - I noticed in videos and pics that my tires aren't bulging and conforming as much as others. I'm running 33 x 12.5 Goodyear MT/R's on 15" rims. How low can I *safely* air these tires down to without too much risk of blowing a bead. I've been staying around 18-20 PSI per a recommendation made by a cousin that's really more in to flinging mud and using the loud pedal - probably adding greater stress to the bead.
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Airing down...
- Thread starter boostleak
- Start date
XJOFFROAD
NAXJA Forum User
- Location
- Washington State
I had some 35" mtr and they wouldnt show a bulge till around 8-10 psi. I run a bfg krawler at 6 psi.
Mosephus
NAXJA Forum User
- Location
- Duncanville, TX
The simple answer is go lower.
WheelinJR
NAXJA Forum User
- Location
- Portland, Oregon
I ran my 33" Interco TrXus at 10psi regularly on basic steel wheels.
MTR's are stiff, they won't bulge much when they're at 18-20
MTR's are stiff, they won't bulge much when they're at 18-20
- Location
- NE Texas
I have Boggers, I run 18psi street, 5psi trail, and it still a little stiff.
On my old 31" (Street tires..remember? lol) i ran anywhere from 8-12psi on the trail..
I would say, try 10psi on the trail, see how it does, In my opinion, i wouldnt worry about rolling a bead untill your heavy on the throttle at less then 8lbs..
On my old 31" (Street tires..remember? lol) i ran anywhere from 8-12psi on the trail..
I would say, try 10psi on the trail, see how it does, In my opinion, i wouldnt worry about rolling a bead untill your heavy on the throttle at less then 8lbs..
But we can't forget - you piss excellence. I'm pissing a solid "meets expectations" at the moment... Ah, what the hell. I'll give it a try this weekend.
LOL, the "street tire" comment came from someone else - I was just quoting. I think it went something like this: "I'm not sure I'll be able to make it up that nasty bit if trail up ahead being that I'm open/open". Some dude standing behind me said, "Sure you can, that crazy dude (he actually used your name, which I've forgotten - sorry!) on street tires made it".
Funny thing is, my wife and I spent Memorial Day weekend up at a Mt Hood cabin with an old buddy of mine. He's not a car or truck guy at all. Within minutes of pulling up to the cabin, he says "You go four wheeling with THOSE tires? They don't look like they'd do very good off road". I just couldn't get him to grasp WHY they work so well. My fault, I suppose.
I have the exact same tire and will usually air down to 10-12psi when in Moab. Has worked well for me and haven't blown any beads.
2xtreme
NAXJA Forum User
- Location
- Kayak Pt, WA
Finding the pressure you need to air down to is a process and will vary on all sorts of things including the weight of the vehicle, size of wheel, etc. It is also dependant on the age of the tires, so what pressure might work well when they are new may not work when they are in the middle of their life and might change again later in their life.
Start the process something like this:
1. Air down all 4 tires till you can see a significant bulge in the bottom of the tires (probably between 6-12 psi).
2. Consider the difference in performance of the vehicle for traction and lack of lateral support while cornering.
3. Adjust tire pressure slightly up if lateral support while cornering is not aceptable, or air down slightly if traction should be better and lateral support is still excellent.
4. Record air pressure
5. Use this air pressure as a starting point. If over time you don't have issues with loosing a bead and traction is good you might have found your optimum pressure.
This pressure will change significantly until the tire is broken in.
Michael
Start the process something like this:
1. Air down all 4 tires till you can see a significant bulge in the bottom of the tires (probably between 6-12 psi).
2. Consider the difference in performance of the vehicle for traction and lack of lateral support while cornering.
3. Adjust tire pressure slightly up if lateral support while cornering is not aceptable, or air down slightly if traction should be better and lateral support is still excellent.
4. Record air pressure
5. Use this air pressure as a starting point. If over time you don't have issues with loosing a bead and traction is good you might have found your optimum pressure.
This pressure will change significantly until the tire is broken in.
Michael
mojojojo
NAXJA Forum User
- Location
- Gresham, Oregon
thats where i have been running my 33X12.5 BFG MT's for the last year. i was running approx 15-18 prior to that. i will say you will be amazed at whata few PSI will do ! ! ! i have gotten a lil braver over time. i am a big chickin shit though when it comes to loosing a bead. but needless to say i never have (knocks on wood). . . . and i have had decent traction when i needed it . . . . most of the time.
this is where everyone will jump in about my failed attempts at mini rubi, and sinking to my axles in snow, etc . . . hasta
wait for it . . . . .
- Location
- NE Texas
arty:
2xtreme
NAXJA Forum User
- Location
- Kayak Pt, WA
I would argue that if you think there is a large difference in performance between 18 and 12 psi, you will likely be more shocked at 8 psi and again at 5 psi.
Also, if you haven't lost a bead than you might not have a good idea of what additional potential you have for additional potential and when/where you can use it safely.
Having said all this, what is it that worries you guys about loosing a bead?
It's not like it is difficult to fix.
Michael
Also, if you haven't lost a bead than you might not have a good idea of what additional potential you have for additional potential and when/where you can use it safely.
Having said all this, what is it that worries you guys about loosing a bead?
It's not like it is difficult to fix.
Michael
swbooking
NAXJA Forum User
- Location
- Riverside/Running Springs, Ca
Ive pretty much ran all my tires at 10psi and havent had any problems at all. (Tires have ranged form 32s to 35s and all different brands)
Ba-Riedo
has frame envy
- Location
- redmond/bellingham, wa
1-3 psi in the snow, 6-12 psi on trails and rocks (depending on how fast I will be traveling) with beadlocks.
-Alex
-Alex
GreenbeltXJ
ACTUAL WHEELER
- Location
- silverdale, wa
when i ran the same wheel tire combo i was at 5psi and 3psi in the snow. never lost a bead, even when winched sideways. with the BFG MTs i went down to 8psi. i think any tire does best under 10 psi depending on the way the driver, drives. meaning dont rally it when they are that low..
fubar XJ
NAXJA Forum User
- Location
- Bothell, WA
I run my MTRs at 11 on the trail, I haven't played with them enough in the snow but I'm going to go down to 7-8 next time I encounter significant amounts of the white stuff. 11 seems a pretty good balance, lets them belly-out on the trail but is still stable enough to run fire roads at reasonable speeds.
mojojojo
NAXJA Forum User
- Location
- Gresham, Oregon
its freekin work. . . . sheesh ! work sucks. wheelin's supposed to be fun. wrenchins an "at home" thing.
:laugh:
RlCHARD CRANlUM
NAXJA Forum User
- Location
- GuateMolalla
Originally Posted by 2xtreme
Having said all this, what is it that worries you guys about loosing a bead?
It's not like it is difficult to fix.
Michael
its freekin work. . . . sheesh ! work sucks. wheelin's supposed to be fun. wrenchins an "at home" thing.
:laugh:
Just remember to take that valve stem out before you torch it.
I ran lower pressures this last winter than ever before. Down to 3-4 pounds, and only lost the bead twice. Both times were due to winching. 10 lbs dry, and 5 lbs in the snow works pretty good on my 12.5 wide tires on 15x8 wheels.
