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-   -   Long arms vs. dropped short arms (http://www.wranglerforum.com/f210/long-arms-vs-dropped-short-arms-2488.html)

JeepnTX 08-05-2006 04:04 PM

Long arms vs. dropped short arms
 
Ok, so OTHER than streetability, what are the advantages of long arms over short arms with drop brackets?

We were discussing this at a local 4WD club meeting the other night. 2 TJ's, setup identically. One with an RE longarm & 38's, the other with short arms, I believe they were Tera drop brackets, & 38's.

They both flex very well, BUT, the one with the short arms had alot more flex than the long arm kit. The owner was blowing out shocks, bending sheet metal in his comp cut and had to have limiting straps. His shocks are mounted inboard at the top, maybe that has something to do with the over-flex?

The clearance was near identical, as the bottom of the drop brackets were at the same spot the middle of the long arm was.

I know flex is overrated if it's useless flex, but I was always under the impression that longarms were wanted for more flex?

mrbigjeep 08-05-2006 05:20 PM

longarms also help a lot with the stability of the rig along with of course flex

bluvikng 08-05-2006 05:25 PM

By replacing the short arms with longer arms and relocating the mounting points on the frame, one can address all of the evils presented by lifting the short arm suspensions over 5". The ingenious solution helps to retain the stock wheelbase, and virtually eliminates rear steer, skateboarding, oversteer, and axle tucking. But it is not a modification for the faint of heart as it requires a bit of surgery to the frame. It is also quite a bit more expensive than a standard short arm lift, since both the arms and the skidplate are replaced.

One of the guys in our Jeep club, with a 6" short arm kit, actually lost his whole front axle as he climbed over a steep obstacle. His axle literally folded up under the Jeep, breaking everything loose. Going the cheaper route does not always pay, especially over 5" of lift.

JeepnTX 08-05-2006 05:39 PM

Quote:

Originally Posted by bluvikng
By replacing the short arms with longer arms and relocating the mounting points on the frame, one can address all of the evils presented by lifting the short arm suspensions over 5". The ingenious solution helps to retain the stock wheelbase, and virtually eliminates rear steer, skateboarding, oversteer, and axle tucking. But it is not a modification for the faint of heart as it requires a bit of surgery to the frame. It is also quite a bit more expensive than a standard short arm lift, since both the arms and the skidplate are replaced.

One of the guys in our Jeep club, with a 6" short arm kit, actually lost his whole front axle as he climbed over a steep obstacle. His axle literally folded up under the Jeep, breaking everything loose. Going the cheaper route does not always pay, especially over 5" of lift.


Is it because of the geometry angles? If so, the drop brackets help with that... I'll get pictures later...

jeepersandcreepers 08-05-2006 06:05 PM

Long arms are used to correct the extreme angle for the axles encounter after a tall lift. Generally we recommend long arms for TJs for any lift past 5". When you lift your TJ past 4" the angles get past the design limits for the axle brackets and on the frame. This is why long arms are used and mounted in different locations so they correct the extreme angles. The long arms allow for a larger radius travel and will be handle the exteme travels when flexing off road.

4Jeepn 08-06-2006 09:15 AM

Shounds like the one guy need longer bump stops. As for the long vs short debate.. each has pro's and cons. i run short arms as I have not seen enough difference off road to justify going to long for the type of wheeling I do. For some folks they feel there is. Then again I have seen a bone stock 78 CJ-5 with dry rotted tires go up a rutted muddy rocky hill that was giving the built jeeps problems thus making us all look stupid.

JeepCrawler98 08-06-2006 11:47 AM

The extra flex was probably a factor of shocks, as it almost always is - not the control arms. On TJ's in both suspension setups - that's just where the limiting factor lies. There is SOOOOOOOOOOO MUCH more to suspensions than just raw suspension travel.

Off road - the long arms will achieve the dialed in suspension values such as antisquat, roll axis, reaction points, etc. more closely, under more circumstances, than a short arm. This makes it more predictable and consistent off-road. However - you do sacrifice by losing a bit of ground clearance over a longer distance (remember that dropped short arms also lose clearance).

The issue with the short arm is not just the fact that you lose optimum geometry almost immediately off-road, but the fact that you're dropping the mounts at the frame means that you're putting more stress and leverage on the stock bracketry as you now have more leverage on it; just something to think about. About the only benefits of the short arm would be a bit of extra clearance after the arms 'end', and lower cost (I think it's cheaper than the $900-$1300 long arm upgrade kits?)

When you start getting into situations where you're consistently jacking up tires in the air, and teetering/unloading your suspension because of it - that's where the main benefits of long arms lie as they do a MUCH better job at keeping this down (not to mention the extra stability, related to this, in steep hill climbs/descents). On fairly level boulder crawling, trails, or 'muddin' - about the only benefit is the smoother ride really.

Then there's the obvious difference in road manners as well - but I wont go there as it's not a factor for you.


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