airing down on regular wheels...no beadlocks

NickMaul

NickMaul

Well-Known Member
Joined
Jul 4, 2009
Location
Norfolk, VA
after all the mud this weekend at URE i figured out street pressure aint to good in mud. i have 31" thornbirds that are 12.5" wide on 10" wide wheels.

how low can i bring the pressure down before i have to worry about loosing or breaking a bead?

yeah thornbirds arent the best but im short on cash and i can settle with thornbirds for a little while longer

nick
 
Probibly would go between 15 and 12 psi w 12.50s on 10" wide rims. The wider the rim, the harder it is keep on the bead. My tires have a thick sidewall and will fall off the bead below 10 psi (13.5 on 10" wide rims). <------That is not normal for most light truck tires.
 
Alot depends on how much the vehicle weighs that they are on. We drive sammi's at 6-8 PSI most of the time and have only lost one bead in 15 years and tht was during a comp. We are running 35/12.50's on 15x8 rims.
 
I would try around 15psi, that might be a little conservative. Start airing down and wait til you see the sidewall start bulging, that should be a good start. With the 10" wheels, I'd be a little worried about rolling a bead.
 
oleblue said:
after all the mud this weekend at URE i figured out street pressure aint to good in mud. i have 31" thornbirds that are 12.5" wide on 10" wide wheels.
how low can i bring the pressure down before i have to worry about loosing or breaking a bead?
yeah thornbirds arent the best but im short on cash and i can settle with thornbirds for a little while longer
nick
Click to expand...
What diameter are the wheels? If they are 15's or 16's, you should be fine somewhere around 15psi, maybe a little less. If they are 16.5" wheels, I would go no less than 15 and probably aim for something closer to the 18-20psi mark. The 16.5's don't have a safety bead, so it is MUCH easier to push a tire off the bead.
 
I am planning on running between 10-15 on my 35x12.5s on a 15x8 rim. Like others have said, a 8" wide rim will keep a bead better at lower psi than a 10" wide rim will. What did you air down to at the end this weekend?
 
Safest thing is to drop your PSI a little at a time during a trip until you find the point that still feels safe, won't loose a bead, and gives you the performance you desire. But like others have said, a 10" rim is not ideal on 12.5's, 8" rims would be better.
 
durnzuki said:
Alot depends on how much the vehicle weighs that they are on. We drive sammi's at 6-8 PSI most of the time and have only lost one bead in 15 years and tht was during a comp. We are running 35/12.50's on 15x8 rims.
Click to expand...

That is because you are using a narrow rim. With a 10" rim and 12.5" tire I would not go below 12 - 15 psi.
 
8" wide rims w 12.5+ tires are commenly known as poor mans bead locks.
Sometimes it can be tricky to reseat a bead on wider rims. I usually takes alot of air and as Upnover said carry a ratchet strap. If you cant get it to seat use a strap that can fit in the center tread long ways around the tire and tighten it till it pushes the bead back on.
Luckly my tires are so stiff that If i blow a bead I can turn the wheel/tire straight and hit it with my CO2 tank.
Oh yea ether and a match will seat rims but be careful it will vucanize the tire and rim together or worse blow up.

***********WARNING***********

(please do not try this... especially in the forest these guys have experience. Not good for a trail fix cause you could burn your rig and youself not to mention the whole trail system)





Do Not Use Too Much or You Will ....

 
yeah my rims are 15x10 and the tires are 12.5" wide. so i figured that somewhere around 15-20 psi would be safe. since i said safe is that an okay tires pressure to run from eldorado to the trails at ure or should i look to air down when i get to hunt camp or something?
 
I would suggest that you can go to 15 psi easily. That would also be OK to drive from/to The Outpost. One thing you do have going for you is that the Thornbird is a hard compound and is a stiff tire so it might have less chance of rolling off the bead.
 
I run 33x12.5 Truxus MTs on stock 15x8 canyons. Ive gone down as low as 10psi but I worried all day ab rollong a bead. IMHO 15psi is a good all around pressure...
 
I've run 11-12psi with 37x12.50 MTRs on non-beadlocked 15x8s on my heavy-ass bronco for years with no issues. I've been in tippy situations with a lot of weight on one wheel at a wierd angle where spotters have about crapped themselves thinking my tire was about to pop off, but it's always held. That's probably why I don't go below 11 psi. Not going to push my luck.
 
BigClay said:
I am planning on running between 10-15 on my 35x12.5s on a 15x8 rim. Like others have said, a 8" wide rim will keep a bead better at lower psi than a 10" wide rim will. What did you air down to at the end this weekend?
Click to expand...

So does that mean you object to running 14.50's on a 6.5" wide wheel? LOL
 
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