Running 40's

[susee80]

I finally got the 40's installed on my Gladiator last week. First impressions, it looks great! Ride is pretty good I think it can be better. I went with 40x13.50x17 Cooper's. I have 17x9 Method wheels. I do have a slight rub at full lock. The installer had a hell of a time getting the old 37's off and dinged up my wheels. They ordered me some new ones but they struggled getting the tire off the bead, because of the bead gripper. I am running them at 32 psi right now and might go lower, I will chalk test when I get a chance. I do have a little road wander and vibration at 55MPH. They used balancing beads instead of weights, anyone have an opinion on this? I'd also like to hear opinions on what upgrades I should be considering to keep this thing safe, reliable, and as roadworthy as possible? (Apex booster, sector shaft brace?) It currently has a Clayton 3.5 ride rite which has been great. I don't do any rock crawling but do get it off road a bit, hunting/snow etc. I'll be honest its mostly a pavement princess.

Sponsored

 

[Gvsukids]

They used balancing beads instead of weights, anyone have an opinion on this?

Those are used in semi tires all the time.

 

[BlueScapegoat]

sooo... where are the pictures?

 

[susee80]

Best I could do real quick.

 

[BlueScapegoat]

That bronze/sarge green is the best color combo imo

 

[susee80]

Those are used in semi tires all the time.

I've heard that, I just don't have the experience to know if this is better than traditional stick on weights.

 

[susee80]

That bronze/sarge green is the best color combo imo

People love it or hate it, it has really grown on me and I get lots of compliments.

 

[zuki_dan]

I am running 40" trail grapplers and tank beadlocks.

I put 8oz of airsoft pellets in each tire when assembling the beadlocks. This method is more of an active balancing. There will be times the feel unbalanced until the beads move around to balance the tires. There is also the problem of not enough weight in the pellets to balance out the tire. I notice more in balance when the tires are cold though and figure possible flat spots until the tire warms up from driving.

Your truck looks great and I assume you are around 4.5" backspace which is not offset enough for 40's when flexed out or full turn. I have the 3.5" backspace wheels and the still touch the inner fenders at full flex and at full turn the passenger tire will touch the side of the grille.

 

[rharr]

I would truss the front axle. The FAD housing starts to crack in half at 38". From what i have seen about people reporting broken FADs.

 

[susee80]

I am running 40" trail grapplers and tank beadlocks.

I put 8oz of airsoft pellets in each tire when assembling the beadlocks. This method is more of an active balancing. There will be times the feel unbalanced until the beads move around to balance the tires. There is also the problem of not enough weight in the pellets to balance out the tire. I notice more in balance when the tires are cold though and figure possible flat spots until the tire warms up from driving.

Your truck looks great and I assume you are around 4.5" backspace which is not offset enough for 40's when flexed out or full turn. I have the 3.5" backspace wheels and the still touch the inner fenders at full flex and at full turn the passenger tire will touch the side of the grille.

Maybe Ill have them add some more beads, I concur that it does seem to smooth out after warming up a bit. The wheels are -12 offset so 4.8". The rub isn't bad, maybe an excuse for new inner fenders. I don't see myself max flexing this thing often or at all. All in all for a 40" mud tire its pretty good.

 

[JTR178]

Axles. Start with the axles.

 

[Pescado]

I would hope you plan on regearing with 40's. I have 35's now but won't move up to 37's until I regear

 

[zuki_dan]

Maybe Ill have them add some more beads, I concur that it does seem to smooth out after warming up a bit. The wheels are -12 offset so 4.8". The rub isn't bad, maybe an excuse for new inner fenders. I don't see myself max flexing this thing often or at all. All in all for a 40" mud tire its pretty good.

Forgot to add earlier that I run around 30-32 psi for even wear across the tires. It is surprising how well it rides on 40's. I am also on about 3.5" lift with split rubicon fender flare

 

[susee80]

I would hope you plan on regearing with 40's. I have 35's now but won't move up to 37's until I regear
It’s a diesel, and honestly it has plenty of get up and go. I’ll consider gears in the future. When I went to 37s from stocks it didn’t feel any different. Obviously I’ve lost some MPGs.

 

[SgtMajTomahawk]

So, I'm going to jump in here before the "You're going to vaporize your axles" comments start rolling in heavy.
I originally had no intent to go bigger than 37s on my Gladiator. I have the Max Tow package, which has the slightly beefier D44 wide axles that come on the Rubicon. I've since added 5.13 gears and Ox air lockers front and rear. I'm running 40x13.50r17 Cooper STT Pro tires and cheap Vision aluminum 17x9 non bead lock wheels.

I'm on a Metal Cloak lift with 4in springs and a 3/4 added spring spacer on the back to help with added weight on the back of the truck.

I do rub at full stuff and hard over to the driver side. The inside of the tire rubs the anti rock arm from time to time when I am flexed out to the driver side. My offset on the wheels is -12. I tried running an extra 1.75in spacer and that actually created more issues with the back of the tire rubbing hard at full turn at the rear of the tire on the inner fender.

My goal was to keep a low center of gravity, but what I found going to 40s is you end up having to trim and cut and correct clearance issues you really didn't plan on. Had I gone to a 6in lift it would probably be much easier, but it's a daily driver and I do wheel and I wanted a low COG.

All that being said the big elephant in the room is am I going to snap my axles? I think the answer to that really depends on what kind of driver you are. Are you the type that goes hammer down to muscle over that obstacle or are you the type that takes it slow, picks a good line, backs off if it doesn't look or feel right, and isn't afraid to pull line if need be?

I have learned to be the latter. Does that mean that 40s are safe and there is no concern running them on stock axles? Absolutely not! Every time I go out wheeling I am anxious and stressed thinking "Man is today the day I snap something" but that also keeps me grounded and focused on driving with finesse and patience vs slamming my Jeep all over the rocks like money is no object to me.

I did a lot of research before making the move to 40s. I looked at tire weight most of all and the type of wheel/tire combo I was going to go with. The Cooper STT Pro in 40 weigh in at 90lbs. By comparison a 38in Nitto weighs 88lbs. By sticking with aluminum non bead lock wheels I save some more weight.
A friend runs 38in Patagonia tires with KMC bead locks and my wheel/tire combo comes in 2 lbs lighter than his.
Now I know that some will chime in about centrifugal force and the tire diameter and how that equation adds stress to components. A 37 or 38in tire spinning i no the same as a 40in spinning even if the weight is comparable.

I spent a lot of time searching the internet, youtube, instagram, etc reading and watching video of others experimenting with 40s on Stock D44 axles.
What I found is people are able to not just run 40s but wheel on 40s and stock axles with only minor upgrades.
Every time I see a post about a broken axle the first thought in my mind is "What was that driver doing that contributed to that failure" almost always you find out that the axle housing or axle shafts failing were a result of the driver abusing or being too aggressive.

There is a good video from a guy in Okinawa (I dont know his name, but he is in the military stationed there.) His channel is TewlTalk and he is very knowledgeable. Very good channel if you don't follow him you should. Anyway, he did a video comparing the current Gen D44 axles to the 1 tons from just a few years ago. You can watch that video here:

In the video he compares the newer D44 axles and what he found was the current Gen D44 HD axles are very close to being as big as 1 ton axles were a few years ago. 1 tons have 35 splines and our current D44 have 32. etc.

I have also watched and followed others who don't just drive to the mall, but actually wheel 40s on stock axles and manage to do just fine. Below are a couple of videos that inspired me:







For me the big reason I decided to go to 40s was while on 37s even with a 4in lift I was always on my belly and/or dragging my ass and getting hung up. I was having to really be aggressive getting over things. Since I've gone to 40s I just roll right over everything with little effort and am able to clear things I couldn't before, which is to be expected.
So am I worried about snapping axle shafts and Ujoints? Absolutely! Do I drive with caution on the rocks? Absolutely!
I do have a truss kit for the front, but I've heard mixed opinions on whether a truss is really worth it or not. Everyone talks about the FAD being a weak point so maybe a truss just for that purpose is worth it IDK. I do have plans to replace front and rear axle shafts and with a little extra go to a 35 spline on the rear.

I will acknowledge this though. Had I known then what I know now I would have just gotten D60s from the start instead of getting gears, lockers, truss, shafts, etc. The price of beefing up a D44 to run 40s is not far off from just getting a set of axles and the piece of mind getting overbuilt D60 axles is worth it.
I do like the lightweight feel of 40s on the stock axles, but you have to be very careful.

Sponsored