PDA

View Full Version : What are people with the stock 18's airing down to when taking them off road????



TJeep_1999
03-26-2015, 10:25 PM
Not new to Jeeps, but new to JK's (114 miles on my 2015 Sahara!!!). The 18" wheels are really throwing me though... For the life of me I can't quite figure out why Jeep is putting these huge rims on the Wranglers now. Anyway, tire pressure is up in the 45 PSI's normally and that's way higher than I've even ran on the smaller 15" rims on my older TJ's so I'm not even sure where to start.

I ALWAYS air down when hitting trails b/c you get better traction on rocks and are less likely to damage the tire.

What are people with the stock 18's airing down to when taking them off road????

If I'm searched challenged and this is already discussed please just put a link below... Thank you!

olram30
03-26-2015, 10:29 PM
yikes, 45 psi is way to much for on road. off road, try around 15-18 on factory tires.

NV375
03-26-2015, 10:44 PM
For the street if you have stock size tires look at the tag on or by the drivers door. I bet it says something like 32psi or 35psi. No reason to go over what it says on the label for stock tires. Sometimes for oversized tires slightly lower. Be prepared to air down every time it goes to a dealership. Some people working at the dealerships think they need 44 psi.

TJeep_1999
03-26-2015, 11:05 PM
For the street if you have stock size tires look at the tag on or by the drivers door. I bet it says something like 32psi or 35psi. No reason to go over what it says on the label for stock tires. Sometimes for oversized tires slightly lower. Be prepared to air down every time it goes to a dealership. Some people working at the dealerships think they need 44 psi.

Yep... 45PSI brand new straight from the dealer. The Jeep is less than a week old. I didn't even think to check the door jam as I just assumed the dealer would deliver a brand new vehicle w/ the correct specs... lesson learned. Ironically, I thought it was really high PSI, but figured it was the 18" rims and thinner tire (my mtn bike gets 65 PSI :brows:). FYI the door spec is 35PSI.

So I'm safe airing down to 15-18 then w/o worrying about loosing a bead on 18's? That's not too far off from what I used to run w/ my 15" rims and 31" tires (~12 PSI)

NV375
03-26-2015, 11:19 PM
Yep... 45PSI brand new straight from the dealer. The Jeep is less than a week old. I didn't even think to check the door jam as I just assumed the dealer would deliver a brand new vehicle w/ the correct specs... lesson learned. Ironically, I thought it was really high PSI, but figured it was the 18" rims and thinner tire (my bike gets 65 PSI :brows:)

So I'm safe airing down to 15-18 then w/o worrying about loosing a bead?

I won't make any promises. 15 seems to be common for air down. All sorts of things can influence my choice of air down pressure. If I know I will be driving fast and hard I don't go down to 15. My wife's ability to tolerate being in the jeep off road also affects my choice to air down. For the most part if you had learning experiences (mistakes) with your TJs those will be similar in your JK. I am more conservative airing down when solo. Also when solo I try to have two air sources.

stweasel
03-27-2015, 12:52 AM
I usually air down to about 18-20 on the trails and have had no issues. I don't rock crawl but I'm not just on fire trails either. I doubt you would have any issues at 15 but I wouldn't go any lower as I don't trust the Bridgestone, as I haven't heard much good about them

JKAnimal
03-27-2015, 01:46 AM
I usually air down to 13 on the trail and I do some moderate Rock climbing. I run 28 on the street because it makes for a much better ride. The chalk test says 28 is still a great pressure for tread contact.

I'm running 17" rims and 37s. I don't think an extra 1/2" radius difference in wheel size is enough to change what pressure you run on the trail or street.

TJeep_1999
03-27-2015, 02:04 PM
Thanks for all the replies! The trails open up here in about a week and I'm curious to see how she'll do bone stock. Will be interesting... Thanks!

tpietzsch
03-27-2015, 03:44 PM
My Nittos on 18s do well at 13lbs when off road. Haven't popped a bead.