I may be a dumb f$%k, but I cannot figure out what the advantages are for using J arms.

I have seen them on the curry suspensions and I have seen them on a number of custom jobs, but I just wonder what the advantages are.

This is what I have seen read about the curry set-up, with respect to J arms:

"The Currie Long Lower Arms wrap under the housings front and rear. This gets rid of a lot of the strange TJ suspension movement when out in the extreme stuff. For example - the front axle seems to want to climb over a steep vertical ledge instead of wanting to travel back under the vehicle like a stock TJ does."

I have also seen Currie state that with this system you get more articulation with less suspension lift.

So can someone please explain to me just how J-arms work and why they are supposed to be so good?

Thanks in advance

Rod

J-arms function on a similar theory to that of long arms, but long arms can create problems when climbing ledges, etc. The J-arms Currie use mount as close the the axle as stock, with the geomety benefits of long arms.

Originally posted by YellowCJ
J-arms function on a similar theory to that of long arms, but long arms can create problems when climbing ledges, etc. The J-arms Currie use mount as close the the axle as stock, with the geomety benefits of long arms.

okkkkkkkkk.......... now explain why? Im having a hard time seeing the short J arm being able to mimic a long arm?

by mounting the arm to the back of the axle instead of the front you get a longer arm, so it behaves exactly like having longer arms because you do :flipoff2:

I thought that the advantage of a long arm suspension was that the angle between the arm and the chassis was reduced. This is supposed to give a smoother ride. So it has nothing to do with the arm length, only the angle. The fact is that a longer arm gives you a smaller angle.

However if you use a J arm, then because the arm has to travel under the axle, it actually has a steeper angle than a normal long arm kit. So again it doesn't make sense to me, this whole it's alonger arm thing.

Can anyone else help?

Rod

Originally posted by rocket
I thought that the advantage of a long arm suspension was that the angle between the arm and the chassis was reduced. This is supposed to give a smoother ride. So it has nothing to do with the arm length, only the angle. The fact is that a longer arm gives you a smaller angle.

However if you use a J arm, then because the arm has to travel under the axle, it actually has a steeper angle than a normal long arm kit. So again it doesn't make sense to me, this whole it's alonger arm thing.

Can anyone else help?

Rod

it doesnt matter if the damn arm is S shaped, its the angle between the mounting points that matter.

if the j is used to increase the length of the arm then why do the currie arms wrap under the axle rather than over:question:

I am getting ready to do my upper and lower arms, and have been pondering the Currie's fow a while now. I run mostly mud and no road at all. I will be using coils with an adjustable height.

Im not to worried about ground clearance since Im running 44+ tires, but if I could wrap the bar over the axle, clearance would be even better.

The only advantage I can see with going under the axle is that it would kind of act like an anti-wrap device. But, the upper links control that so..... Why not run them over the axle:question:

When we were in Las Cruces during the Warn event, I got to talk to the Currie guys about the J-arm thing. The reason they have them under the axle is that the coil spring is placed right above the lower control arm with stock like TJ mounts. The arm would have to go through the spring. Seems to me that, in rockcrawling, it is nice to have everything slide. By putting them on the bottom, it allows a rock to slide under the axle instead of hitting it directly.

Try to picture the control arms mounts from the side. The stock mounts are below the axle. When the rear end trys to wrap, the lower control arm, mounted straight under the axle trys to push forward. When using short arms, and a tall lift, this forces the rear end up, causing strange handling. The long arm kits just make the angle less, so the lower arm isn't pushing up as hard. Now picture the Currie arms mounted behind the axle. When the axle trys to wrap, the mounts behind the axle push the arm down, having no effect on the frame end of the arm. The arms would work exactly the same if they were mounted over the axle, as long as there were no clearance issues. I hope I have cleared this up without confusing anyone.

also having the arms mounted on the back helps w/ traction. It's a little of drag racing theory. W/ them in front you can power break your vehicle. W/ them in the rear it will push the front tires. We get our arms from high country 4x4 in Denver. Look at our set up on www.brownsfabrication.com. It's easy to do if you have the tools. We also use TJ 4" springs.

Originally posted by pure-adrenaline
also having the arms mounted on the back helps w/ traction. It's a little of drag racing theory. W/ them in front you can power break your vehicle. W/ them in the rear it will push the front tires. We get our arms from high country 4x4 in Denver. Look at our set up on www.brownsfabrication.com. It's easy to do if you have the tools. We also use TJ 4" springs.

I looked at the setup on the Pure Adrenaline Jeep on the Brownsfabrication site you listed and have a question: Doesn't that traction/hookup (via leverage if I understand correctly) only occur once the axle wrap rotation has maxed out, and the arms are stressed downward via contact between the top of the arm and the bottom of the axle tube? Just trying to figure out what you mean. Thanks for any info!

Also, by chance do you have any contact info for High Country 4x4? I couldn't find their site via a web search. Thanks!