Trev1006

Ok so I think this is fab. More of a fab question.....I know home made long arms have been covered alot. But my question is I want to make a long arm kit(which I have done before) without using the Johnny joints. I have made short arms without using them. I just want to make the arms stationary instead of adjustable. Would this greatly reduce the flex of the long arm? I just dont have the money for the joints and can make the jointless arms at work for free. As long as I get my pinion angle and such right on I think I would be ok??

Jordan1996 ZJ

so are you saying that you just want to use poly bushings? or are you going to just attatch the arm into the axle

Trev1006

Oh sorry I want to use poly bushings I never used from another lift kit. I just dont remember ever seeing a long arm kit that diddnt have Johnny joints on the lower arms.

jonjon99xj

its very possible, but not recommend on a wheeled rig, they dont flex as well as the johnny joint would. But if you wanted to use poly bushings you better make sure your numbers are correct or your axle might be out of line, good luck. also you cant adjust your caster angle if you only use bushings

Gatchmo5710

save up for the right bushings. you only need one on each arm. make a 3 link and get 3 johnys for pretty cheap.

Trev1006

Like a triangulated 3 link? Ive not done that before but im sure I can Google it. Last time I bought my joints from rustys I think and they were kind of expensive. Anyone have a better place? And yes this sees alot of trails but its also my dd.

Trev1006

ok, so i think i decided on what to do. buying johny joints is out of the question at the moment and for at least 6 months. my jeep projects fund has been hi-jacked and re named "wedding Fund" lol. but i cand believe i diddnt think of these before. my shop has cases and cases of these inserts for parts that we make for hyundai factories to support the assembly lines so they are real tough, and already threaded. so i will thread the ID of the dom tubing and put these at both ends of my long arms with jam nuts and poly bushings from my short arm kit. then i will machine a wrench flat on my dom tubing arm for adjustmenst. and i think i am going full four link. i have seen kits that keep the arms mounted to the framerail with a bracket as well as ones that have a full new cross member with the arms mounted here. im guessing the ones with the new cross member is the best?

ps i will cope those inserts for a better fit before i weld them together.

b. lee

That was going to be my exact suggestion. I'm considering the same thing for a 3-link currently. I would suggest one thing different though. Leave out the jam nut.

With both ends using fixed bushings, the ram can't rotate more than a couple degrees as the axle articulates, which is the benefit here. Using the jam nut would only fix your arms in position and would only serve to eliminate this flex.

Sure folks will say that JJ or heims are the only way to go, but that's incorrect.

If you mount your frame ends to the frame, you'll need some more beef there, like frame stiffeners. I'd recommend them anyway. The crossmember mounting allows more flexibility, like moving your frame ends further inboard for more tire clearance, or mounting higher for better clearance.

Trev1006

Ok thanks. I think I will do the frame mounting with the extra stiffners. Why do you think you would go 3 and not 4 link? Im still up in the air.

b. lee

Less material, less cost, easier to design, but most importantly, no binding and better articulation. Maybe a moot point though, because the limiting factors of shocks, tire clearance, and brakelines will probably inhibit the flex moreso than the bind inherent in a 4-link.

Trev1006

Im drawing a blank on the name but I think The arms im leaning toward are the ones that have the straight lower arm(not radiused) and they have the upper arm mounted to the lower arm about a third of the way up. Looks really easy to design and real easy to adjust. I dont hit rocks alot, mostly twisty woods trails and hill climbing with your basic mud.

b. lee

That's a radius arm suspension. It's not named that because it has any radius in it, but because it forces the axle to travel in a fixed radius by design.

A good design, and a very effective one, and very popular in the aftermarket. It has some inherent shortcomings though, probably the most detrimental to you would be wheel hop, as it does tend to come un-planted under power. Add to that weight transfer from uphill trails/climbs, and the front end can give up a lot of traction compared to a good 3- or 4-link design.

Ultimately though, everything is a compromise.

Trev1006

Thanks you seem to be very knowledgeable on this subject.

Trev1006

Would that design be much worse than just using an old school parallel 4 link?

b. lee

No, I wouldn't call it worse, just slightly different. I'd be willing to bet that most drivers wouldn't be able to tell the difference in performance offroad, and on road would be very similar.

The good thing about building your own stuff is that you can also modify your own stuff just as easily. Build a radius arm set up now, it's fairly easy. If you don't like it 100%, cut off your top links and build an upper link for a 3-link (or 2 uppers for a 4-link if you like).