Jeep Wrangler Forum banner

1 - 20 of 51 Posts

·
Registered
Joined
·
5 Posts
Discussion Starter #1
Went on my first offroad trip this weekend. Had a blast! I'm running 315 70 17R BFG AT's, one of the guys I was with recommended that I air down to 15psi. Everything was going great until I tore a tire up. 15psi seems way to low. Anybody have an idea where I need to be? Thanks in advance!!
 

·
Registered
Joined
·
249 Posts
Depending on what rim width your running 15psi is actually a good starting point. Did the tire unseat from the bead or get punctured?
 

·
Registered
Joined
·
813 Posts
I go down to 14 in the front and 12 in the back. The higher the psi the more likely you are the tear the side wall IMO, but I never go below 10 psi
 

·
Registered
Joined
·
1,249 Posts
I go to 12-15 psi...the PSI probably had nothing to do with your tire damage...and everything to do with what you ran over/into.
 

·
Registered
Joined
·
813 Posts
I go to 12-15 psi...the PSI probably had nothing to do with your tire damage...and everything to do with what you ran over/into.
At 15psi your probably right but once your above 22-25 the tire won't conform to the rock or what ever you go over. No matter what psi your at you shouldn't try to rub your side wall on anything (sometimes there is no choice) it's the weakest part of the tire and you can't patch it.
 

·
Registered
Joined
·
387 Posts
Since this is an airing down thread i figured i could ask.. Im getting 35x12.5x17 tires on stock rubicon wheels what is sort of the optimal air down measurement that is safe enough to not pop the bead (i see the OP has a very similar tire size and maybe this can help in the future)
 

·
Registered
Joined
·
80 Posts
don't mean to jack but....

got stock rims (17) and MTRs on them (255/75/17)

what should I air down to if I'm going on sand?
 

·
Premium Member
Joined
·
7,920 Posts
I aired down for the first time in my life this past Sat at the advice of the owner of where we were wheeling....and since it was not something I normally do...I guessed at it. Didn't have a TP gauge with me....I let the air out for a "15 second count". I generally run 26-28psi...at the end of the day when it came time to air back up I found I was at 10-12psi......I was one of the few Jeepers that didn't get stuck all day...but I am also a little more "cautious" about where and what I do off road....I did pull a few other people out though......
 

Attachments

·
Registered
Joined
·
249 Posts
Anybody have an idea where I need to be?
what should I air down to if I'm going on sand?
optimal air down measurement that is safe enough to not pop the bead
theres is no set in stone pressure for all rigs/wheel tire combos. this is something you have to play with and find out what works for you. the wider the rim, the more air you need to keep the beads set. generally when new guys come out on trail rides with our club and ask this i tell them to start at 15psi unless i see their running 10" wide rims on 12.50 wide tires, then i recommend starting at 20psi. different tire manufacturers will have softer/stiffer side walls then the next guy in line, so you gotta play with the pressure. i run 35" DC Crushers and they work very well at 15psi on stock moab rims. another good way to get a base line for where to start is: pull the valve stem core out and let the air out until you see the sidewall of the tire start to bulge a good bit, reinsert the valve stem core (or use one of those fancy smancy tire deflator tools.) how far you air down mainly depends on sidewall stiffness, rim width, and vehicle weight. basically the lower you can go the better.
 

·
Premium Member
Joined
·
695 Posts
don't mean to jack but....

got stock rims (17) and MTRs on them (255/75/17)

what should I air down to if I'm going on sand?
12-15 psi. for soft sand. If it's as hard as Daytona beach, don't bother airing down at all.
 

·
Registered
Joined
·
2,367 Posts
If you pop the bead off, thwts why you have a spare. You can spray starting fluid in the tire and light it up and reseat it but thats dangerous. If you have a powerful source of air you can just push it on the bead while airing it up....

I go to silver lake alot if its raining i can run a higher psi than if the sand is dry.....

Psi needed varies so much......
 

·
Registered
Joined
·
290 Posts
In soft sand I use 8 or 7.5 psi for all tires. It's unstoppable. I have stock 16" wheels and 245/75/16 Hankook Dynapro ATM E rated. I find this to be my ideal set up for the region and will probably keep it as long as I have the Jeep. It never sinks and never looses a bead. Please keep in mind that the sand is generally extremely soft where I am.
 

·
Registered
Joined
·
290 Posts
Also when I've helped others reseat beads with compressor, we usually jack up the tire. I've seen people try it while the tire is on the ground, it doesn't seem to work. This may be due to variance in tires, though.
 

·
Registered
Joined
·
383 Posts
Do you guys typically carry a small air-pump in the back of the Jeep to get the PSI up again on the return trip on the road?? If yes, any good brands / makes you would recommend a noob like me?
 

·
Registered
Joined
·
290 Posts
Yes (to compressor question). But I think the best brand here (Camel) doesn't exist in the US. Get a larger one from a decent company or you'll have to wait for ages.

Also, maybe in the US you'll get a good hose with it, but here... They ALL burst with frequent use. Carry some nautical tape and zip ties to repair it, and get a heavy duty hose made, with sealed fittings, if you will use it a lot.
 

·
Registered
Joined
·
813 Posts
Do you guys typically carry a small air-pump in the back of the Jeep to get the PSI up again on the return trip on the road?? If yes, any good brands / makes you would recommend a noob like me?
I have a little on board compressor, but most guys in my club use a Co2 set up. They are liquid Co2 that is pressurized to 2000psi and lasts them 3-4, sometimes more, trips filling 35s from 5psi to 50psi and some run their lockers off of it too I believe since I never hear a compressor from their rig. If you do get an on board air system try and get one with a 100% duty cycle or at least above 70%
 

·
Registered
Joined
·
277 Posts
15 might be too low in that big of a tire. The idea is to deflate until the sidewall is 75% of its normal height. Do some experimenting in your driveway to figure it out. It's always good to have a little extra room to lower the pressure if the dirt get too loose.
 

·
Registered
Joined
·
317 Posts
I am too interested in air down/up tools (deflators/compressors) anyone can recommend.

I took my JK out on it's first real off-road adventure this weekend and we aired my 315/70/17 Duratracs down to 20psi. This was a really bumpy road and the 10psi drop made a huge improvement in ride. I can't say if it was the lower air, tire tread or what, but I was very impressed with the hook up. That said....I could easily see going down to 15psi and trying that next time.
 
1 - 20 of 51 Posts
Top