I guess everything is relative, but I ran my 2014 Wrangler at 30-32 psi... on the street. Airing down was 12-14 if I was on my street tires (KO2s) or 8-10 on my dedicated offroad tires. I can't imagine that 30psi in the rocks is going to feel very comforable. Even on my stock setup, back when my Jeep was new and running 255/75-17s, I'd air down to 14 as a matter of course. I'd think with an 18 you would be fine at 16-18psi.

As far as compressor, big fan of the 400p, which suits my P400 very nicely. I've had the Viair for 7 years, a lot of refills, never had it cycle out due to temp even when filling 8 big-*** tires back from 12-25 psi.

And if you do it with anything approaching regularity, I'd replace the plastic yellow coily cord hose that comes with all of them with a Flexilla. Sooooooo much easier to deal with than that coiled one that is fighting you constantly and trying to pull your compressor off of your motor or wherever you've set it.

 

I too was intrigued with this statement. When I went to 16" steelies for my Wrangler the front calipers were a touch too large to fit without rubbing. I took a pneumatic die-grinder to the spot on the calipers that was touching, took a sixteenth off the metal, sprayed it with rustoleum or something, and ran them for 7 years without rubbing or issues. Just wondering how close the rears on the D110 are to rubbing on 18s, and if "trimming" is possible to get 18s to fit? If you're planning to replace them anyway if it doesn't work, no bothers if you somehow ruin them trying.

17" OEM wheels up front, 16" Wheel Vintiques in back for a day till I got the fronts ground down a tad:



Yeah, I know it's ghetto to grind them, but what can I say? I'm a low-rent Wrangler peasant at heart.

 

thanks for the feedback. When I say”trimmed down” I really mean ground off with a grinding wheel. I took off the “ridges” on the stock calipers to make room for the 18” wheels. I had to take off about 1-16 to 1/8” on each of the calipers. Honestly, the calipers are very beefy and I wasn’t concerned at all about removing the excess material - it almost seemed like the cast was just sloppily made when they manufactured the calipers.

 

Glad to hear it! I may wind up being the first to do it with a Defender, if somebody doesn't beat me to it.

 

You're confused man. The guy you were just talking to already did...

 

Look again.



I think I might get the dremel out also. A couple of minutes with a Carbide might be all that is needed for the rear calipers on the p400

 

Oy it's not my day.

I should take the time to read more than skim.

Ok let's start over, I'm confused man. 🤪

 

Interesting thread on airing down. I’d be wary of airing down on tough rocky trails with the adventures on 20’s. There have been quite a few posts about pinch flats off road with these. I also was told to not air down at LR experience for the same reason. And of course, there’s the TFL video where they stupidly accelerated into a sharp rock on aired down Adventures. It’s always a trade off between traction and flat protection, but unless you really need extreme traction, I wouldn’t air down 20” Adventures below 30 unless I was on a beach where pinch flatting is not a risk. At LR experience I was told to leave them up at 50psi and had no traction problems at all. Have left them there for some routine off road trails with some rocks and have not pinch flatted.

 

I think the conventional wisdom regarding airing down is based around the assumption that you aren't also offroading on essentially low profile tires.

 

Resurrecting this thread as I'm heading out next weekend to Big Bend National Park in Texas. Terrain is dirt with some sharp rocks. I have the 19" rims with OEM Goodyear "off road" tires (not Duratrac). After reviewing everything above, it looks like there are several suggested approaches:

Option 1: air down to 30/32 psi (umberto)
Option 2: air down to 18/20 psi (BJS1234) -- this was used in Grand Canyon/Sedona which I think will be reasonably similar to the terrain in Big Bend. I'm concerned this might be too low though and greater likelihood of flats?

Is the main reason for airing down increasing the tire's contact patch (in particular for sand, or more aggressive sidewall traction in rock crawling)? I saw some mention of ride comfort too, but perhaps there's a deflation point where this doesn't matter as much?

Based upon what I've seen here, I my current plan is to go with 30psi with the goal of limiting the chance of flats like TFL experienced. I'd love to get some other feedback here if there are other opinions/thoughts.

Thanks!
RedAustinIX (Ed)