Davidengbe

That headline...

Well. Tried to search, but it all gets blurry to me.

I recently installed the RE 4,5" longarm on my JK, along with 37" tires. Got it to the alignment shop to get the whole setup properly. Never been totally satisfied with the overall handling of the Jeep since the lift (bouncing/vibrations). Today, when checking the protocol from the shop it says "Jeep Wrangler *TJ* 2003"... Makes me think something isn't like it should be. Tried search and found many different explanations, so I'd like to know the perfect numbers for the following on my JK, front respective rear:

1. Camber

2. Caster

3. Toe-in

4. Tire pressure (37"x13,5"x18")

5. Anything else to check/think about?

Any help appreciated!

chuck45

Since nobody else has answered I'll try to be a little help. I've got the RE 3.5 kit with 35" tires though I considered what you have.

Camber isn't adjustable on a JK w/o the expense of off-set ball joints.

Caster: Stock is 4.2 and you will want to bump that up to 5 or 6. I initally had 6 but dialed it back to 5 when I installed JE Reel 1350 driveshafts. I couldn't tell the difference.

Toe in: stock is 1/16. I went to 1/8 and it made a big difference. I have been told that 37"s can actually require 1/8 TOE OUT to drive properly.

Tire Pressure: I think most people tend to run too much pressure with these big tires. I am running 28 in my 35's. You could probably run 25-27 in your 37's.

Anything else? Is everything torqued properly. Are your axles centered properly? Is your steering wheel centered?

I would call Jason at RedRock 4x4 in Utah. He has a JK with your exact setup and he installed it himself. He said his rides better than stock so he could probably give you the best real world info. I bought my Re 3.5 from him and he's good people.

blkpearl

Good info, yea i have the firestone lifetime alignment, and have been playing, with the adjustments,

I am running 37s @ 28psi on a 15x8 rim, and that seems to give me a good wear pattern(done with chalk test)

i have had the caster adjusted between 5-8, and for my jeep 7 is about right, i and totally agree about the 1/8 tow, makes a huge difference. with all the alignments that i have done to me jeep either offroad or just readjusting. one or the combo of the two make a difference. will help with the squirley or jerky steering.....

thankfully the dude that does my alignment at firestone is a jeep guy, and is very good and he will listen for my inputs, and we talk about what has been working or not etc.....

Davidengbe

Thanks guys, very helpful and informative! I appreciate your help, and will have it checked right away!

I just adjusted the angle for my J.E. Reel 1350 rear driveshaft, and it was way out of angle - so hopefully this will also help a bit... tomorrow I'll adjust the front one, as it's also out of angle (not so much, though).

chuck45

Just noticed the mention of your 15x8 wheels. Many, many moons ago, around 1975 or 76 I bought the first set of 36" "Gumbo Monster Mudders" Dick Cepek sold. I mounted them on a 3/4 ton Ford 4x4 PU which had stock 16.5 wheels. I bought a set of 15" wheels with the 8 bolt pattern (the tires were only available in 15" size at the time). BIG Mistake! The truck waddled going down the road due to excessive side wall flex. I could grab the side of the truck, start to rock it and move it 8" sideways.

Giving all you have done, and the need to run low air pressure to get a decent ride, I'll bet your small wheels are causing the problem. Things might impove temporarily if you try running the tire at max air pressure to see what happens. I'd try to find somebody with a set of 35's or 37's mounted on a proper 17" wheels, borrow them, and see if that makes a difference.

One other factor that came up in my earlier experiment is that 15" wheels had lower standards for strength than the 16.5 wheel that was stock and the wheel itslf had more flex.

I have heard of 37's needing as much as 1/4" toe out; but that seems kind of extreme to me.

You may have to get new wheels and tires to get decent performance.

blkpearl

i have two jk, my wife has my old 35s on a 16x10 rim they ride fine,(those were my old tire and wheels)..... but i upgraded to 37s that i got from a buddy with less than 300miles(cheap), they were on a cj5 his wife wouldn't drive the jeep unless he went back to the smaller tires??

initally I had bought 15x10s because I like the look and loved the great tread where, that i got with 16x10s,...but popped a bead at nags head....tested some 15x8, rode nice and that were i stayed

as far as strength, 15 or 16, tire or wheels, 30 years ago wheels and expecially tires the technology and compounds were way different, side walls thinner, etc......now we have puncture guard sidewalls........
and flux capacitors

as far as wheels... not all wheels are created equal.....

16in jk steel rim or a 16in for f350???.

what is stronger 15 or 16 or 17

the other difference between 15 vs 16 is the load ratings, 16s you can get D++ tread compound..and you cant with a 15

air pressure.....i had to max psi, rode like a rock, chalk tested tire showed over inflated wear pattern with chalk, so i droped psi, and chalk tested over and over til i got a nice even pattern....as far a a wagging prob, the only time it is noticiable is when i am aired down 12-15, and in a off camber situation, the sides roll a bit,.....but ya have to change the way you drive with any modified vehicle,

if i were running a 37 13.5s or wider i would run a 10in wide rim, but it is only a 12.5 so that is why i running 8s...

when i first got my jk wondered if i could put 15s on just to open up a variety of tire sizes and prices.

everyone has there own opinions.... that why we build new and impoved things, or sometimes not....... hey that is how we learn and make things better.....i learned alot of good info from this site, that has saved me some headaches....


wow, sorry so long started typing like a 12 year old school girl in love.....