Short arm vs long arm lift question

Ddays

Hooked
I don't think the LA kits provide a better "ride" per se, as that would be more in the category of spring/shock combination . The way I understand it after speaking with a Clayton rep is that they give you more stable and settled handling characteristics on the road and especially at higher speeds. I've never ridden in a Jeep with a LA kit but talked to Jeffj on our last Rausch trip and he couldn't praise enough how well his Jeep handled with the EVO DTD system that utilizes the those LA arms. I'm still doing some research but so far it looks like the EVO system is the way to go. I don't like the Clayton arms in the front. Their uppers connect to the lowers midpoint and for some reason that doesn't look optimal to me.

Edit: As far as your question regarding cost: That's what all of this shit comes down to isn't it? I think if you do a lot of highway driving, like as in long distances, the LA kits would be worth it by reducing driver fatigue. If you do a lot of local slower speed driving maybe not so much worth it? Also, the higher the lift the more the benefits of a LA kit I would presume. I'm looking at these kits for the stability benefits when using the Jeep to pull a travel trailer (3000# range). Still a lot of $ though.
 
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jknikos

Member
At 3 inches a long arm is not worth it imo. The jk's stock arms are long enough. If you get adjustable arms and correct your caster and pinion angles you will be fine. The lower you lift your jeep, the better it is, just get the best quality springs, shocks and arms you can afford.
 

DWiggles

Caught the Bug
this topic is very much opinionated, but I will say this:

I have the EVO 4" long arm kit, and I'm happy.

I have seen MANY build threads on this forum of members who had the standard evo enforcer kits, and evo bolt on coilover kits and LOVED it... but when they install the long arms, they wondered why they waited so long...

I guess the moral of the story is, The long arm is "better" but if you don't know what your missing, the stock length arms aren't "bad" at all? :idontknow:

I'm sure this post isn't helpful at all, but Its the best way I can manage to explain the difference. If you HAVE long arms, your going to be happy, if you DONT have long arms, your going to be happy *UNTIL you drive a quality long arm jeep? :thinking:
 

Ddays

Hooked
this topic is very much opinionated, but I will say this:

I have the EVO 4" long arm kit, and I'm happy.

I have seen MANY build threads on this forum of members who had the standard evo enforcer kits, and evo bolt on coilover kits and LOVED it... but when they install the long arms, they wondered why they waited so long...

I guess the moral of the story is, The long arm is "better" but if you don't know what your missing, the stock length arms aren't "bad" at all? :idontknow:

I'm sure this post isn't helpful at all, but Its the best way I can manage to explain the difference. If you HAVE long arms, your going to be happy, if you DONT have long arms, your going to be happy *UNTIL you drive a quality long arm jeep? :thinking:

How would you describe the difference in how the Jeep rides and handles between the two? The way it was described to me was that the LA kit is more stable at speed and feels more planted on the road. Would you agree with that or is it something different?
 

2DMTN

New member
"I'm sure this post isn't helpful at all, but Its the best way I can manage to explain the difference. If you HAVE long arms, your going to be happy, if you DONT have long arms, your going to be happy *UNTIL you drive a quality long arm jeep?" :thinking:[/QUOTE]

Well said!

LA it is then. Cost is certainly a factor but more important to do it right the first time, I've already learned that lesson. Thanks for all the input.
 

wayoflife

Administrator
Staff member
If you like the look of a 1980's sky high lift, long arms are the way to go as they will correct your suspension geometry and provide a smoother ride on pavement and when driving hard and fast across the desert. If you're going to run a more reasonable 3" lift, factory JK arm lengths are plenty long enough and there really is no need for long arms. I have installed and driven both setups over the last 10 years and on the 4 JK's I've owned and 2 I still own. If money isn't a factor, they're nice to have with 3.5"-4" of lift but not really something I'd say you "need" till you get above the 4" range.
 

DWiggles

Caught the Bug
How would you describe the difference in how the Jeep rides and handles between the two? The way it was described to me was that the LA kit is more stable at speed and feels more planted on the road. Would you agree with that or is it something different?

The only time my jeep didn't have long arms was when it was at stock ride height. :idontknow:

But from what I gather, the long arms make the jeep absorb bumps at speed like a stock height jeep (assuming all other suspension components are quality/balanced) meaning, with the long arms, the arc the axle travels is more vertical, and less "forward/back" and as a result, provides a smoother, more refined feel. when you lift a jeep, the stock arms pivot on the same radius of curvature, but they are set a sharper angle at the new, higher ride height. when the front tire hits a bump, this causes more "feel" to be transferred horizontally; rather than vertically into the shock and spring.

WARNING: DRASTICALLY simplified example!!
Lets say a stock jeep control arm is at angle "λ" and the factory "horizontal force" is described as "x" [the resultant of a bump I.E. the amount of force transferred horizontally (NOT through the shock/spring)]
now you lift your jeep
the control arm of interest is now at angle " σ" which is greater than angle "λ"; now the "horizontal force" can be described on an order of magnitude greater as "x + x*sin(σ-λ)"

referencing the variables above, the purpose of the long arm is to get "σ" AS CLOSE to "λ" as possible, as "σ" approaches "λ", "x*sin(σ-λ)" approaches zero; thus, the "horizontal force" approaches the factory value or "x+0".

50s-class-nerd-costume.jpg
 
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Ddays

Hooked
If you like the look of a 1980's sky high lift, long arms are the way to go as they will correct your suspension geometry and provide a smoother ride on pavement and when driving hard and fast across the desert. If you're going to run a more reasonable 3" lift, factory JK arm lengths are plenty long enough and there really is no need for long arms. I have installed and driven both setups over the last 10 years and on the 4 JK's I've owned and 2 I still own. If money isn't a factor, they're nice to have with 3.5"-4" of lift but not really something I'd say you "need" till you get above the 4" range.

In your opinion Eddie, would a LA kit help with stability in towing a 3000# travel trailer? Honestly, thats my entire interest in the LA conversion.

The only time my jeep didn't have long arms was when it was at stock ride height. :idontknow:

But from what I gather, the long arms make the jeep absorb bumps at speed like a stock height jeep (assuming all other suspension components are quality/balanced) meaning, with the long arms, the arc the axle travels is more vertical, and less "forward/back" and as a result, provides a smoother, more refined feel. when you lift a jeep, the stock arms pivot on the same radius of curvature, but they are set a sharper angle at the new, higher ride height. when the front tire hits a bump, this causes more "feel" to be transferred horizontally; rather than vertically into the shock and spring.

WARNING: DRASTICALLY simplified example!!
Lets say the stock jeep control arm is at angle "λ" and the factory "feel force" is described as "x" [the resultant of a bump I.E. what you feel when you drive over a bump]
now you lift your jeep and the control arm is at angle " σ"; now the "feel force" is described as "x + x*sin(σ-λ)"
it is increased by that angle

referencing the variables above, and again, this is a VERY simplified example the purpose of the long arm is to get σ AS CLOSE to λ as possible, as σ approaches λ, x*sin(σ-λ) approaches zero; thus, the "feel force" approaches the factory value of x.

View attachment 265793

Gotcha - thats precisely how it was 'splained to me.

Funny - that's exactly how I pictured you ;)
 

jeffj

Caught the Bug
I am by no means an authority on this subject, but I can tell you my observations and experiences. I'm not going to get into when I owned a tj, it is totally a different animal.
First JK I put 3.5 inch mid arm suspension lift. I think this is normal, but I netted out more like 4inches or a little more. The roads here in WV are not flat and I had a lot of back and forth and constantly adjusting the steering. I then added the PSC kit which made it a little more touchy, but by no means not doable. When I would hit a nice flat road, I would not notice it all.
Second JK with long arms and 40's. On the roads that would drive me crazy with my other set up, it now drives 95% better. I do have a lot nicer suspense and a better set up, but it seems like the back and forth feel is almost gone. I still have a little back and forth feel, but I think that is a little rear steer coming from the rear track bar. That's my take on my limited experience.



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DWiggles

Caught the Bug
I am by no means an authority on this subject, but I can tell you my observations and experiences. I'm not going to get into when I owned a tj, it is totally a different animal.
First JK I put 3.5 inch mid arm suspension lift. I think this is normal, but I netted out more like 4inches or a little more. The roads here in WV are not flat and I had a lot of back and forth and constantly adjusting the steering. I then added the PSC kit which made it a little more touchy, but by no means not doable. When I would hit a nice flat road, I would not notice it all.
Second JK with long arms and 40's. On the roads that would drive me crazy with my other set up, it now drives 95% better. I do have a lot nicer suspense and a better set up, but it seems like the back and forth feel is almost gone. I still have a little back and forth feel, but I think that is a little rear steer coming from the rear track bar. That's my take on my limited experience.



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I'm not sure how your previous jeep was setup, but the caster plays a huge roll in "back and forth" feeling in the wheel. I noticed a HUGE improvement immediately when I installed my 10° PR44 (unlimited) vs. the factory axle. I changed nothing else (well, I did the progrips too)... just something else to consider
 

jeffj

Caught the Bug
I'm not sure how your previous jeep was setup, but the caster plays a huge roll in "back and forth" feeling in the wheel. I noticed a HUGE improvement immediately when I installed my 10° PR44 (unlimited) vs. the factory axle. I changed nothing else (well, I did the progrips too)... just something else to consider

Yes, your correct, caster has a lot to do with how it drives and how stable it feels. I was at 4.5 with old jeep and 5.5 now.
I was feeling more of back and forth and then needing to correct constantly. Like it was coming from the rear. I think for steep caster it feels like it is darting in the steering.


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2DMTN

New member
Thanks for all the responses. If I go with 4" it will be a long arm, 3" will not. I am still undecided on which lift though. This forum seems to be very pro EVO. So I've narrowed it down to EVO, Synergy and Rock Krawler. Very hard to know what to choose. Scared to make the wrong choice, everybody has a reason why they like one over another. Thanks again for all the input.
 

wayoflife

Administrator
Staff member
Thanks for all the responses. If I go with 4" it will be a long arm, 3" will not. I am still undecided on which lift though. This forum seems to be very pro EVO. So I've narrowed it down to EVO, Synergy and Rock Krawler. Very hard to know what to choose. Scared to make the wrong choice, everybody has a reason why they like one over another. Thanks again for all the input.

What a person chose to buy for their Jeep is typically going to be what they recommend and a lot of folks on here have chosen EVO. That being said, people here also run Synergy and Rock Krawler and the latter more so if they live in the east coast. EVO has some of the softest springs you can get, uses high quality components and has been the leader when it comes to coil over suspension systems. Since you're in SoCal, you might want to stop by EVO and talk to them.
 

VeruGE*144

Caught the Bug
Long arm vs short arm

Thanks for all the responses. If I go with 4" it will be a long arm, 3" will not. I am still undecided on which lift though. This forum seems to be very pro EVO. So I've narrowed it down to EVO, Synergy and Rock Krawler. Very hard to know what to choose. Scared to make the wrong choice, everybody has a reason why they like one over another. Thanks again for all the input.

Evo will give you a height they actually advertise. I just changed my springs to EVO 4" which is actual 4" of lift vs AEV 4.5" which gave me 5.25" of lift and were a lot stiffer. I must say I Iike the ride of EVO plush rides and they perform amazing off-road. The rest of my kit is still pretty much AVE with stock arms and drop brackets on the front. Also have their bilsteins 5160. In my opinion drives good even with the short arms. Although I am planning to upgrading to long arms in the future and they will be EVO long arms.


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