Another Tire PSI Question
05-14-2018, 06:17 PM
#1
JK Enthusiast
Thread Starter
Another Tire PSI Question
So running Mickey Thompson ATZ 285/75/16, E Load rated at 20 psi on stock 16” rims. See chalk pics. Per the picture should I continue to lower pressure? Is it acceptable to run them safely at this pressure?
If it is acceptable what would be a good pressure to run off road without risking blowing em off the wheel bead?
05-14-2018, 07:39 PM
#2
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That is definitely lower than I would run on the street. Part of your problem is the narrow stock wheel. A wider wheel would give you a better contact patch with the road, plus your gas mileage must suck at that pressure.
05-15-2018, 05:06 AM
#3
JK Jedi
Dang, 20psi in a 33 is way low regardless of chalk test IMO. That E rated tire isn't gonna flatten out much....I know you have bumpers and stuff, but you are generally still pretty light. I'd think most people with 33s are running in the 30-32psi on road, with 35s more like 28-32. Even with 37s, I run ~27psi on road. And as Ryan noted, you're always gonna have the trade off of tire wear vs. fuel economy, so it's just searching for that happy median while mixing ride comfort on the mix as well.
Off road, same thing....no real right or wrong. 15psi very safe. You could probably even go to 12psi and be ok, but I've not had a 33 much less on a 16" wheel. That said, you'd be really surprised what it takes to break a bead on one of these while off roading.
Off road, same thing....no real right or wrong. 15psi very safe. You could probably even go to 12psi and be ok, but I've not had a 33 much less on a 16" wheel. That said, you'd be really surprised what it takes to break a bead on one of these while off roading.
05-15-2018, 06:42 AM
#4
Super Moderator
Yep, that's pretty light on the pressure and like resharp001 said, an E rated tire is too heavy. Heck I run E rated tires on my 2500 HD and tow 10-12K with it. You really should be running a D or C rated tire. (I run a D rated tire on my JKU which weighs 5738 lbs)
05-15-2018, 10:14 AM
#5
JK Enthusiast
Thread Starter
Son of a biscuit..... Wish I had known better about load rating on tires. Caveat emptor for sure. I'll have to do some research see if Mickey makes a D or C load tire. They've been great on the wheeling so far. Well I suppose I'll just run em down until worn, it's not like I can go back to Discount and say "Yeah you ordered the wrong load rating." After I've put a few hundred miles on em.
05-15-2018, 10:28 AM
#6
JK Jedi
Yeah, it's not the end of the world. You're still gonna get a lot of use/life out of them, maybe just not the optimal amount due to wearing a bit heavier in the middle. I'd still bet 50k miles or so though. For the type of things you're looking to do, nothing wrong with a C rated tire next time, or a D. I'm kinda shocked that those are E rated tbh.
Just to ease your concerns about breaking beads while in the middle of nowhere.....my first set of 35s was a C rated tire. I'd air those down to 11/12 psi and put them through a workout, really beating up the sidewalls and squishin em down in very offcamber situations up against washouts and such. Once or twice I'd get a tiny slow leak at the bead and would have to reseat....but I'd reiterate SLOW LEAK. I air my 37s down to 10 or so with non-beadlocks and no issues wheelin hard. Only one time have I been with someone that blew a bead and it was our own dumb error of winching off a jeep parked sideways.....and putting a ton of stress on it the jeep pulling it against the sidewall when it only had 10psi or so in it. Blowing a bead is not a common thing in most off roading IMO.....even at pretty low tire pressures and with traditional rims. You're much more likely to puncture a tire.
Just to ease your concerns about breaking beads while in the middle of nowhere.....my first set of 35s was a C rated tire. I'd air those down to 11/12 psi and put them through a workout, really beating up the sidewalls and squishin em down in very offcamber situations up against washouts and such. Once or twice I'd get a tiny slow leak at the bead and would have to reseat....but I'd reiterate SLOW LEAK. I air my 37s down to 10 or so with non-beadlocks and no issues wheelin hard. Only one time have I been with someone that blew a bead and it was our own dumb error of winching off a jeep parked sideways.....and putting a ton of stress on it the jeep pulling it against the sidewall when it only had 10psi or so in it. Blowing a bead is not a common thing in most off roading IMO.....even at pretty low tire pressures and with traditional rims. You're much more likely to puncture a tire.
Last edited by resharp001; 05-15-2018 at 10:30 AM.
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05-15-2018, 11:16 AM
#8
JK Jedi
Son of a biscuit..... Wish I had known better about load rating on tires. Caveat emptor for sure. I'll have to do some research see if Mickey makes a D or C load tire. They've been great on the wheeling so far. Well I suppose I'll just run em down until worn, it's not like I can go back to Discount and say "Yeah you ordered the wrong load rating." After I've put a few hundred miles on em.
05-15-2018, 11:47 AM
#9
Super Moderator
Son of a biscuit..... Wish I had known better about load rating on tires. Caveat emptor for sure. I'll have to do some research see if Mickey makes a D or C load tire. They've been great on the wheeling so far. Well I suppose I'll just run em down until worn, it's not like I can go back to Discount and say "Yeah you ordered the wrong load rating." After I've put a few hundred miles on em.
