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lupinsea 01-21-2005 03:41 PM

Max. Flex vs. Useful Flex and The Anti-rock
Maximum Articulation, Useful Flex,
and the Curri Anti-rock

By Lupinsea

Often in discussions and various threads here on there are quesions of a good swaybar disconnect system or methods to develop the maximum flexibility out of the TJ's suspension system. Invariably, someone in these threads will mention the Anti-rock offroad swaybar which is then followed by questions about what is it, how does it work, and which develops "more flex." This post is an attempt to explain the idea that there is a difference between "Maximum Articulation" and "Useful Flex" as it pertains to offroad situations and how this relates to the Anti-rock and typical quick-disconnect systems.

I will tell you right off the bat that you will develop more "maximum flex" with any of the quick disconnets than you will with the Anti-rock. But how useful will that maximum flex be? Bear with me . . .

Maximum Articulation
There are some Jeepers that hold the contention that all flex is not created equal. That there is "maximum flex" and there is "useful flex." Maximum flex or articulation is just what it sounds like. Just how much you can completely flex out your particular suspension setup. Max flex will give great RTI numbers and really great pix of Jeeps with tires high in the air and people will say "holy snot, look at that." The quick disconnects are great with developing maximum flex since they completely disconnect the swaybar from the axle.
Impressive, but how much effective force is on
the tire if the spring unseats from the perch?

Sometimes you'll see pictures of Jeeps so flexed out that the springs actually have no load on them and in fact may drop down from the upper spring perch. This is were we get into the idea of "useful flex." When a tire can droop so much that the spring unseats there isn't much weight on the tire. Without the weight there won't be much taction from the drooped tire. In this situation one has to ask what is the practical difference between this and having a tire lifted in the air from a traction stand point?

Useful Flex
So the idea of "useful flex" is introduced. And that is the point at which you can flex out and still get power down to the ground with enough traction. Unfortunately, this is much more difficult to pinpoint because it will depend on many factors such as ground surface conditions, tires, traction aiding devices, specific suspension setup, load distribution, and perhaps other factors. John Currie, who's won many rock-crawling competitions and has a good reputation with the community for thoughtful designs and solutions, approaches the flex issue from the "useful flex" stand point with the Anti-rock.

The Anti-rock is an anti-swaybar specifically design for off-road driving and offroad conditions. Currie carefully engineered the swaybar to balance flexibility with chassis control. It works with the rear swaybar and keeps both front and rear swaybars connected at all times to evenly distribute forces between the front and rear axles aiding traction by keeping the weight on the tires. While much softer than the stock bar the Anti-rock also helps control body sway and lean off-road making side-slope and off-camber situations much less trecherous to negotiate.

I was surprised at the difference in off-road ride after the Anti-rock installation. The Tj felt like it just melted over the terrain. When I'd approach holes, ruts, and drop offs I would expect the TJ to shift and sway toward the depression. Not so. The tire would drop into the hole in a controled way and the chassis remained surprisingly level, balanced between front and rear axles. And the traction difference is noticable, too, especially since I have open diff's at each end. I met guys on the trail who said "oh you'll definitely need a locker to get up that hill, if you have problems, just wait for us." But the TJ would just scramble right up with no hint of any traction problems.

Besides the handling benefits there is also the ease of use. Once the Anti-rock is set up you just leave it alone. The only reason to stop at the trail head is to air-down tires. . . otherwise just roll onto the trail and roll off. No pulling pins or tying the swaybar out of the way. Likewise, when you're coming off the trail you don't have to get under a muddy Jeep and hook things back up in the rain and muck or whatever you just wheeled through. No rocking the Jeep back and forth to line-up pin holes or anything. It simply works very transparently and you forget it's on there.
Click to enlarge: The Anti-rock
installed on author's BB lifted TJ.
No pins to realign or discos
to fuss with

Despite the added control, the Anti-rock does allow a surprising amount of articulation. In one article the author quantifies the difference between fully disconnecting the swaybar and running the Anti-rock:
  • 33.25" fully disconnected (20* RTI = 1050)
  • 32.00" loosest Anti-rock setting (20* RTI = 1011)
  • 31.25" firmest Anti-rock setting (20* RTI = 987)
As you can see, the "maximum articulation" is developed by fully disco'ing the swaybar but the Anti-rock still allows for significant flex while providing the handling benefits. Even at the firmest setting the you only give up 6% of your total flex for all the benefit. And at the looses setting? Less than 4%

The Anti-rock isn't cheap at nearly $300. However, if anyone is considering the $100 JKS or Teraflex quick discos then they owe it to themselves to look into the Anti-rock. Honestly, after runnning with this mod for the last 6 months I would highly recommend it to anyone as it's one of my favorite mods. Especially since you can keep it with your TJ if you upgrade suspension systems and axles.

Additional Resources

Review & Install on a 2" BB Lifted TJ
General Anti-rock Review & Install Pictures
Another Installation Review
Even Stu Olsen Installed One Reviews the Anti-rock Before/after articulation measurements at end of article


bigjohnwhodatis 01-21-2005 03:49 PM

Great write-up! My only concern with the AR is the on-road handling, how is it?

AudioGuru 01-21-2005 04:46 PM

Great write up, and I agree that an Anti-Rock is superior to quick disconnects.

However, the next time you see a TJ flexed so far that a spring is loose, have the driver stop and you go try to lift the drooping tire. Preferably do this with a hook and a hanging scale, so that you can see how much force is being exerted downward by that tire. You'll be surprised. Remember since both springs are inboard of the tires, by having the right front tire stuffed, the right spring will push down on the left front tire, even though the left spring isn't exerting any downward force.

But yes, anti-rocks are sweet and quite a bit more pricy than a disco system.

Jerry Bransford 01-21-2005 08:09 PM

I asked Jay (Lupinsea) to post the above information here that he had written earlier in another thread so I could make it a 'sticky'. Thank you very much Jay for taking the time to make such a well written contribution to the Forum. I hope everyone enjoys it and can put his nicely written information to good use. :thumbsup:

NetJunkie 01-22-2005 07:36 PM

For those looking at the Anti-Rock also check out the Sway-Loc from It costs more, but utilizes two seperate sway bars for onroad and offroad.

redrockyj 01-27-2005 04:28 PM

how much for your antirock jerry? if you do decide to sell it i might be able to buy it off you when my next paycheck comes around as long as its in decent condition. :D

ErikJordan 01-30-2005 10:43 PM

the sway-loc is a fantastic design. the ability to switch back and forth from the anti-rock looseness to the rigidity of the street driving mode is a fantastic concept. from what i understand, and have seen, there are a few minor bugs to work oit on it, but when they are resolved, this will be a must have for off roading tj drivers ;)

slimP 02-11-2005 12:57 AM

Great write-up, thanks :thumbsup:

????? 05-09-2005 12:56 AM

I'll add my 2 cents.

The antirock will 'slightly' limit an RTI score, but in a real world situation, it does not limit flex at all. With the antirock installed I still max out my OME LT shocks, but it offers more resistance throughout the travel and makes it much more stable.

To test it out, I once disconnected the bottom mount of my shock and flexed through a rut with diagonally opposing tires drooping. With the antirock installed on the loosest setting my OME LT shock was completely maxed out and then had atleast 6" between the bottom of the shock, and the shock mount on the axle. Even at that I was still limited by the size of the rut, I believe it could have drooped another 6" before the antirock arm and link would have been straight.

RedSyphon 08-10-2005 10:47 PM

does anyone out there know the performance decreese/compromise for a DD that the Currie anti-rock would cause?

Atm I take corners like a mad man :D Even scare my friends who drive lower riding cars for the hell of it.

But in ther VERY near future (in fact the lift is already on teh truck :banana: ) I will be getting a OME 2.5" w/ a 1" MML & BL.

So I realize I am going to have to take the corners easier as is, altho I am still looking for the option to swerv around say... a crazy suicidal armadillo stuned in my lights :thumbsup:


wil badger 08-10-2005 11:31 PM

as much as i don't like the company have any of you seen this

TeraFlex S/T swaybar

RedSyphon 08-11-2005 08:08 AM

hmmm, i wonder how well it lasts..
seems almost TOO simple to me...
just being abelt o twist a knob and be off that is :)

NetJunkie 08-17-2005 10:10 AM


Originally Posted by wil badger
as much as i don't like the company have any of you seen this

TeraFlex S/T swaybar

The Tera system is a fancy disconnect. It's not like a SwayLoc in that you have an off-road bar. You are either connected or not with it.

wil badger 08-17-2005 10:43 AM

never said it was .just putting it out there .one more to have discos with out having to get under the truck to do it.i wouldn't use it.i just take my swaybars off and throw them in the trash

RowdyMoose 08-17-2005 09:56 PM

has anyone used the Tera setup? And someone please correct me if I'm wrong, but when you flip it to trail, it is just like being disconnected right?

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