boxed control arms

smilesyota · Sep 22, 2005

I'm trying to fit 31x10.5 tires on stock wheels, with a two inch spacer and trimming. The tires are rubbing on the lower control arms on the rolled edge.
Has anyone cut and boxed these arms for clearance.
PS I'm doing this all very low buck!!!

"Wolz" · Sep 22, 2005

If your doing this low buck, adjust the steering stops so the tires don't hit, you won't loose much of your turning radius and it's free.

footdale · Sep 22, 2005

The stock control arms are designed to be weak torsionally, allowing the axle to articulate during flexing. Aftermarket products (good ones) that are made of solid tube use some type of flex joint to allow twisting of the axle. If you box the stock arms, they will be much stiffer and you'll probably wear out the rubber bushings faster, assuming you get out and wheel it from time to time. For daily driving it'll be fine.

Dirk Pitt · Sep 22, 2005

footdale said:
The stock control arms are designed to be weak torsionally, allowing the axle to articulate during flexing. Aftermarket products (good ones) that are made of solid tube use some type of flex joint to allow twisting of the axle. If you box the stock arms, they will be much stiffer and you'll probably wear out the rubber bushings faster, assuming you get out and wheel it from time to time. For daily driving it'll be fine.

SPOBI

Factory control arms were not designed to "twist", that's what the rubber bushings are for.

Boxing is a good idea to gain rigidity for off-road applications if it's done the right way. It has been done.

old_man · Sep 22, 2005

Dirk, I would argue with you on this one. I boxed a set quite a few years ago and tried to wheel them. I promptly broke two arms and almost didn't get home. There is not enough flex in the rubber joints to do the type of flex we push XJ's to off road around here.

If you don't believe me, ask JJacobs. I gave him a set and he tore them up ASAP as well.

olivedrabcj7 · Sep 22, 2005

right and wrong. Its true, the unboxed arms DO flex torsionally which probably does keep them from breaking. however, the jeep engineers probably didnt design them to flex on purpose. it just so happens that the way we use them off road twisting on them, since the rubber bushings are pretty hard, the twisting of the arms does occur and probably needs to occur to prevent breaking them.

footdale · Sep 22, 2005

Dirk Pitt said:
SPOBI

Factory control arms were not designed to "twist", that's what the rubber bushings are for.

Boxing is a good idea to gain rigidity for off-road applications if it's done the right way. It has been done.

Of course rubber bushings allows for some give, but they are definitely not designed for the angles generated from an articulating axle encountered on a moderate trail. That is why I said for daily driving that setup would work fine. Grab a stock lca and give it a little twist. There is enough torsional compliance there to make it hard to believe that it wasn't designed that way.

smilesyota · Sep 22, 2005

Thanks for all the input! I may just bend that lip alittle and adjust my steering stops. I will build some adjustable long arms over the winter.
what kind of failure did the boxing cause, and how was the arm boxed?
Was it only boxed on the bottom?

Dirk Pitt · Sep 22, 2005

old_man said:
There is not enough flex in the rubber joints to do the type of flex we push XJ's to off road around here.

footdale said:
Of course rubber bushings allows for some give, but they are definitely not designed for the angles generated from an articulating axle encountered on a moderate trail

olivedrabcj7 said:
the jeep engineers probably didnt design them to flex on purpose

Exactly, like I said earlier, the arms are not designed to twist. They were designed the way they were with a rubber bushing on each end to handle the "flex" they were designed for, not very much.

This is why you don't see anyone who wheels very much use a factory style arm. We use JKS style/cartridge joints/heims.

jrsxj98 · Sep 22, 2005

olivedrabcj7 said:
however, the jeep engineers probably didnt design them to flex on purpose.

Straight from the horses mouth. I just got off the phone with my buddy who is a Division rep from chrysler corp. He contacted the design department and the engineers stated they were designed for moderate torsional flex..............

XJ_ranger · Sep 22, 2005

Dirk Pitt said:
This is why you don't see anyone who wheels very much use a factory style arm. We use JKS style/cartridge joints/heims.

ive got bushings on 3 of the 4joints per pair of arms on my junk and it seems to work alright...

Procrap LCA's with poly bushings
RE UCA's with SF joints at the body and bushings at the axle (stock rubber)

i think the bushings give more than we give them credit...

that said - i would like to run all hard joints some day...

langer1 · Sep 22, 2005

jrsxj98 said:
Straight from the horses mouth. I just got off the phone with my buddy who is a Division rep from chrysler corp. He contacted the design department and the engineers stated they were designed for moderate torsional flex..............

The key word is moderate, I would think with old hard bushings you would risk cracking the frame mounts also.

RCP Phx · Sep 23, 2005

Something else not mentioned,the stock arms/shock mounts limit the drop-out.Thats why most aftermarket arms have a kick/offset in them.At 5" w/ RE arms I still needed to grind the mounts for optimum travel.

Bounty Hunter · Sep 24, 2005

Consider running WJ LCA's if you want some tire clearance at full-lock.

boxed control arms

smilesyota

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"Wolz"

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footdale

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Dirk Pitt

Adam Dowling

old_man

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olivedrabcj7

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footdale

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smilesyota

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Dirk Pitt

Adam Dowling

jrsxj98

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XJ_ranger

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langer1

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RCP Phx

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Bounty Hunter

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