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How the Metalcloak Duroflex bushing stacks up

267K views 1K replies 177 participants last post by  freeskier93 
#1 ·
Let me first preface this review by stating that I'm in no way unhappy with the performance of Currie Johnny Joints. I've ran them for years and many thousands of miles now, longer than I ran the stock rubber bushings. The goal of this comparison was to put MetalCloak's Duroflex joint up against what I believe to be the 'golden standard' of control arm ends, the JJ. I've had experience with most other joints on the market and the JJ blows them out of the water in terms of durability, simplicity and value.

Before I get started on this review, I think it would be useful to disclose how my preferences have been formed and molded over the years. I started out like any other new Jeep owner, fairly clueless-learning to put the soft top up and down was far more important than what was going on under my Jeep. Before owning the Jeep, I was always interested in cars and tinkering but those two interests were never mixed….in other words, I knew absolutely nothing about suspension. But I met a few guys in the area and decided to try the 'offroad thing.' I was hooked after my first visit to Attica and eventually, those random few guys became very good friends of mine and IndyORV formed. Fortunately, as I started wheeling more often, I started to work on my own stuff more often as well. By the time I got around to swapping in my current axles and moving up to 35" tires, I at least knew what control arms did but that's about it. At that point, suspension geometry and the 'finer details' were still unknown to me.

-early 2009: RK 4 link with Currie lowers
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-You can see the axle wanting to walk under the vehicle
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I remember being very worried about the increase in noise, vibration and harshness (NVH) with Currie arms compared to the stock arms I knew and was comfortable with. Some guy named Blaine told me in a very matter-of-fact tone, "quit worrying about things that don't exist" or something like that. Once I finally got the Jeep back on the road, it had Currie joints all around, maintained the Clevite bushings in the front housing, and was using Rock Krawler triangulated rear uppers with stock frame mounts. On paper, it was an absolute mess but I didn't know that….I just blindly thought that no track bar = better. But it felt great on the road compared to what I was used to-much tighter and controlled but still very compliant. After that, I stopped doubting that guy named Blaine.

-The RK and Currie arms
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-3/2009: Sittin' pretty on 35's
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-Maneuvering 'Wedgie' in Attica
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As I wheeled that setup, I really appreciated the smooth and silent operation of the JJ but hated the new-found hopping as I climbed up rock walls. Once I started to dive into suspension geometry, I realized pretty quickly that the RK kit that I spent so much money on was really screwing things up….I would have been much better off keeping the stock axle mounts and running a track bar, as far as geometry is concerned. And I was already dealing with the frame-side poly bushings and axle-side rod ends being worn out so those had to be replaced. I believe this was about the time I started to develop some wobbles up front, despite having these nice, tight Currie JJ's all around. Once I traced that to the axle housing bushings and removed the arms to inspect, I found sleeves that were nearly separated from the rubber elements….combine that with a few of my stock control arm bushings that showed the same symptoms a year prior, and I really started to understand the limitations of Clevite bushings. Shortly after, I was running JJ's on all ends and the Jeep drove better than ever.

-Climbing a wall in the quarry....well, more like bouncing up it.
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-Suspension getting a bit more proper: Gone with the dog legs and factory frame and axle mounts
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-Rear view of a much-improved modified short arm 4 link
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Fast forward through a bunch of research, wasted time and money, experience with the industry's offerings, some wheeling between busted knuckles and 4 letter words, and suspension variations and we're about caught up. Now it should be somewhat clear why I'm such a "research first" Nazi. I myself wasted thousands of dollars and countless hundreds of hours on parts that would later just be removed and scrapped or sold for cents on the dollar and my preferences reflect that--they have gone from being a puddle of muddy water to a Bushnell scope locked onto a bull's eye. Due to that, I possess a major fault of being very non-receptive to new parts, especially in this segment. I like what I like, I know how to get it, and I don't really care for anything else. This comparison is a rare departure from that.

-This replaced the mangled and bent RK truss and allowed me to run 2.5" JJ's all around in the rear
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-Sittin' pretty with great clearance
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-3 link front with mid-length arms
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-Pushing the axle back
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-Updated 4 link with mid-length arms
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When I first caught wind of MC's Duroflex bushing, I thought, "great, another failed entry into the world of control arm joints." There are so many wanna-be joints out there it's comical and none of them come close to the JJ. But, being familiar with the quality of parts that leaves MC's facility, I gave them the benefit of the doubt and wanted to get a closer look at these. Naturally, I initially attached the Clevite bushing stigma to the Duroflex bushings since they're rubber and use a vulcanized, bonded sleeve. My dislike for rubber bushings is, in my opinion, justified since I've seen plenty of them get torn up and tore up a few myself in years past. Relating these two bushings was my first mistake and I'll gladly confess that. These operate in a very different way than your average Clevite bushing. Just watch MC's video on the Duroflex joint and you'll see that.

-9 months of work complete
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-Box o' bushings
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It got to the point that I had to try these simply to satisfy my own curiosity. I have a never-ending appetite for knowledge and that all starts with hands-on experience so unless I could actually try these, I can only make half-*** assumptions as to how they feel and hold up. You can see my first response to these, along with a fantastic discussion, here: http://www.jkowners.com/forum/showthread.php?t=71064&page=2

This is a nice recap of the Duroflex bushing: http://www.metalcloak.com/2-5-8-ODx2-5-8-W-Duroflex-Joint-Straight-Spud-p/7303.htm

Shortly after, MC posted a video: http://www.metalcloak.com/Jeep-Suspension-Builders-Parts-s/235.htm

Also, here's John Currie's JJ video: http://www.currieenterprises.com/cestore/johnnyjoints.aspx

After watching the video, my tone changed and so did my level of interest. That really gave me a great view on how the bushing actually worked that was second only to hands-on experience. Instead of viewing these like I view all of the other joint offerings aside from the JJ, I viewed them as a very viable option.

-Empty Currie barrel
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-Duroflex bushing inserted into the Currie housing
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Everything you've read so far was written before I ever had the Duroflex joints in my hands. When I first opened up the package and picked one up, my first thought was "damn, that's one heavy chunk of rubber." They feel very durable and could easily kill someone if used as a projectile. There is some flash (excess rubber) left over from the molding process and grooved machining marks present…neither are particularly pleasing to the eye but I don't think either will cause an issue at all. In fact, the grooves in the assembly may help to hold grease. After discussing this with Doug @ Metalcloak, they wanted a rougher bearing surface so that the force required to overcome the friction between the barrel and bushing was not too low. So, the machining grooves are a non-issue and are intended.

-Duroflex misalignment
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Next, I'll just give a brief comparison between a stock type bushing, a JJ type bushing, and the Duroflex bushing. In a control arm bushing/joint, you've got two items-the sleeve and the absorption element around it. In a standard/OE type control arm bushing, the sleeve and rubber element are bonded together. The rubber element is also bonded to the housing or outer sleeve. The sleeve and bushing material are also the same width, leaving little misalignment capability outside of deflection. In a JJ type joint, the ball sleeve is a lone unit that rides inside interlocked, stationary polyurethane bushing halves. It can rotate in all directions inside the bushing and due to the greater sleeve/bushing width ratio, can achieve high amounts of misalignment. Due to the independent nature of the ball sleeve and bushings, there is no self-centering capability. With the Duroflex joint, the ball sleeve and bushing element are bonded, forming a single assembly. That assembly can rotate inside the end barrel, drastically separating it from the OE type control arm bushing. The sleeve/bushing width ratio is also high, allowing for high misalignment capability. But unlike the JJ type joint, the bonded assembly returns to center. More technical discussion on the properties of different ends can be found here: http://www.jkowners.com/forum/showthread.php?t=71064&highlight=deflect&page=16

-Front end complete
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So what kind of changes was I expecting before making the swap? I've ran JJ's for a long time and have been very happy with them. I prefer a tight, 'sporty' ride in favor of the mushy, numb stock ride and JJ's, combined with other items, provide that. On paper, the JJ polyurethane bushings absorb less NVH than the stock Clevite bushings due to their significantly higher durometer rating but in real world application the difference is very small, definitely a tribute to Currie's diligence in finding the correct blend. This allows essentially no longitudinal deflection, providing a near-direct linkage between the frame and axle, increasing positive traction and suspension response. They provide all of the 'good' movement (misalignment) and none of the 'bad' movement (deflection). Something else that should also be considered is the preload between the ball sleeve and bushings. It takes a significant amount of force to rotate the ball and in theory, this could contribute to less compliance over road imperfections like pot holes, speed bumps and fire road surfaces than something that requires less force.

-Attica last weekend
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Due to the fact that MC's bushings have much more absorption material and are made of a softer rubber, it only makes sense for them to provide near-stock NVH absorption. One could also infer that the softer rubber will deflect more. Personally, my thoughts were that the reactions from the smaller road imperfections (pot holes, expansion joints, etc) would be reduced by some small amount. Since this is a comparison between two excellent products, all differences must be taken into account, whether they are too close to measure or not. With that said, one could also derive that a small improvement in cornering will be realized due to the self-centering bushings. Lastly, I do like the one-piece, sealed unit. While I've had no problems with any of the small grit and grime that can get in between the JJ's center ball and bushing halves, it can happen. Remember, I ran these for three years with no greasing or maintenance of any kind and until I took them apart I couldn't have told you they were dry. No noises or other issues. When taken apart, they were dirty and dry as a bone but none of the bushings needed to be replaced. Those are my oldest JJ's and are still in use on another Jeep in Michigan. But with the Duroflex bushing, I don't believe anything will be able to get between it and the housing walls. If you live in a wet, salty, gritty environment then this should be taken into consideration.

Real world results
The front swap occurred on 2/8 and I wasn't able to log many miles before pulling the Jeep back into the garage to set her down for another week of work on other stuff, including the rear bushing swap. But from the miles I logged, I definitely felt a difference, more than I expected. There was no loss in tightness or control but there was a gain in ride quality. It may seem honky, but I mainly based the results on the speed bumps in my neighborhood, with some potholes and train tracks thrown in. With just the front bushings swapped in, the difference between the front and rear suspension when going over the speed bumps was evident-the front just floated right over without any drama and the rear was a bit harsher and 'bounced' over, for lack of a better term. The same difference was felt on most road imperfections and train track crossings. I got the rear bushings swapped in late on 2/11 but wasn't able to take the Jeep for a drive until early 2/16 morning. Conveniently, that also was a day scheduled for the Badlands in Attica, IN. Driving the Jeep over the speed bumps that morning, I can honestly say it was similar from going from 30 psi to 15 psi in my tires.

-Haulin' ***
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-Climbing
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I expected some differences from these, but not quite as drastic as the differences I'm experiencing. When going over these speed bumps before, I always felt the need to slow down a bit so that I don't get bucked. Now, I can speed up and float over them. Everywhere else-expansion joints, potholes, train tracks, etc.-on the road, the results are the same: tight, controlled, extremely compliant. Aside from ride quality, one other change was very evident-noise reduction. I've got a rear bearing issue going on and that provides a wonderful symphony of sound in the form of your standard high pitch whine. Surprisingly, the noise was cut down by a large amount-enough that my girlfriend noticed without me mentioning it, I could comfortably listen to my radio on the highway without having to crank it, and the biggest indicator to me-I was able to hear my tires. I wasn't able to take any definitive decibel tests but I can say without hesitation that at any speed above 30mph or so, I was never able to hear my tires over that bearing, wind noise and all other sources of noise and now I am.

Disclaimer: The source of the bearing noise will be fixed very soon.

-What goes up must come down....with a pillow soft landing
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Now, before my review on the trail, I've got to make this clear-my Jeep was down from 3/12 - 11/12 receiving massive modifications. The last time I wheeled this thing in 3/12, it was a totally different animal than it is now. I've got a longer wheelbase, flatter arm angles, more up travel, larger tires, and different rear shock valving than I did back then. So, these bushings could just be another small piece of the pie. But, keep in mind that I have driven the Jeep over two thousand miles on the road from 11/12 - 2/13 with JJ's so I will assume that the differences on the road will translate to similar differences off of it. In short, I've never been able to go so fast through the whoops…..not even close. And I was comfortable doing it and the Jeep felt in total control. The suspension was silent and very smooth and I was able to outdrive the Bilstein shocks, as they were hot to the touch once I stopped. Again, that may not be definitive enough for some but it's the best I've got. Given the knowledge I possess of my Jeep and how it behaves, I can honestly say that the MC bushings made a considerable difference at speed in rough terrain.

-Trying to hit the Savvy skid
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So, why would the Duroflex bushings make such a big difference when most would agree that going from stock Clevite bushings to JJ's makes hardly any difference in perceived NVH? That's a very good question and one I've been pondering over myself. Maybe as we slowly change things in our Jeeps, we lose track of the initial baseline (stock) and due to the slow rate of change, the aggregate sum of those changes isn't totally felt. Maybe the advantages of the JJ-tighter steering, better constraint and more responsive suspensions feel-overshadow the increase in NVH, making it much less noticeable. Or maybe these actually provide better performance than stock Clevite bushings due to the ability to break away from the barrel. Whatever the answer, I'm not sure. I'd love to take a stock TJ with stock bushings and do this exact comparison-stock, MC, Currie. I think the fact alone that I'm a huge Currie supporter should lend credence and validity to the results I feel and if you doubt any of the claims I'm making, please call Metalcloak and try these for yourself as I did.

-Trussbender
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This doesn't mean others won't experience different results. My Jeep is very spartan-no carpet, no inner fender liners, higher durometer rubber transmission and motor mounts, etc. Simplicity and being lightweight are two key goals of my Jeep so it tends to be a bit louder than a stock, fully carpeted Jeep with soft rubber everywhere. With that said, I think the fact that I realized such significant differences in both ride comfort and interior noise should speak volumes.

I intend to continue to run the Duroflex bushings because I love the way they feel and I'd like to see how they hold up under my Jeep. The long-term durability of these bushings just isn't known. They haven't been around long enough to prove how long they'll last so I'll do my best to get to that point. Until then, the Currie JJ is undisputedly the most durable joint available. But, I enjoy driving my Jeep back and forth to work, to the trail, out to eat, to the bar, etc. and these simply make it more comfortable and enjoyable to do so.

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Obviously, this review will be ongoing. I can take more pictures and will be taking a couple more videos in the near future.

Here's two videos from Saturday @ Attica on Red Trail. All ends are Duroflex.



JJ Deflection test video--as you can see, there is no visible deflection. I'll be doing one with the Duroflex bushings as well.


UPDATE 6/7/13
I've got over 1,000 street miles on these bushings, with more trail miles shortly approaching. I'm still very, very pleased with the results and can say without hesitation that these bushings are one of the best changes I've made. The ride quality is just fantastic.
 
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#891 ·
Ordered my complete set on Wednesday and got 'em today. I was told that it was going to take a few weeks, so I was surprised to get them so soon. Can't wait to experience them, running stockers for now. Too bad it will be a little while before I will be ready for the install.

Jack
 
#898 · (Edited)
How can this be? I ordered my control arms over a month ago and they have not been shipped yet. Emails to MetalCloak have not been answered. They have not returned phone calls either with a status update.

Update:
MetalCloak phoned me back. Was told that the order should ship sometime this week but could not provide a specific day. Was provided with the same information last week when I called and was able to speak to someone.
 
#895 ·
Ok, so I have all 7 of my single adjustable control arms mounted up. Now let me explain why I only have 7 mounted. I bought a set of axles a while back, dana44/30 w/4.88 gears for a great price. Well, the guy was running a 3 link with track bar in the front and stupid me missed the pass side control arm mount missing.(would of gotten them anyway) Now I'm deciding if I'm going to weld on a new mount(pass side) or just keep it as is. The driver side mount has a Johnny joint upgrade but I'm still not sure if I want to keep it this way. As for the arms, they appear to be well made, MC has great customer service and I can't wait to get everything else done so I can really start testing these out. For now I will be keeping it to local roads and speeds under 40 but I will post back once I get a feel for the ride. Imped, I In boxed you but figure your busy enough but if you have any insight, or anyone else for that matter on the front 3 link please pass along your advise/experience with that setup. Thanks everyone.
 
#896 ·
Nothing wrong with doing a proper 3 link with the duroflex joints. However. That OEM style currie joint on the upper isn't quite up to the task to be used as a single upper. Its a 7/16ths bolt if I recall correctly, which is fine when there is a second upper sharing the load, but not big enough for a single upper.

Not to mention the axle side of the arm is a JJ and the frame end is a duroflex joint. Mixing of the two within the same arm is not recommended.

I would get a passenger side upper in as sooner than later.
 
#897 ·
Great review, thanks !
 
#918 ·
the problem for mc is, that out of the 4 joints, theirs broke, the others did not.
that will be seen as weakness by some buyers. real or fantasy, makes no difference to some buyers.

i understand he has a competition rig, and it will abuse parts like no street rig could.
parts a street rig will wear out in 50k miles, a comp rig wears out in 2 races. some people wont see it that way.
some guys dont know what a real competition rig is. to them, their jeep has 35's, so it is a competition rig!

the only problem i see, is that i cant run his joints with other joints. i have a issue with that.
almost all my arms are currie now, so i will be sticking with currie. i cant just change a few joints at a time.
 
#916 ·
That's funny. I brought up the ugly welds to Matson in this or another thread, and he thought I was making something out of nothing, and that he would "eat his hat" if the strength was a concern. I hope his hat is yummy!

That said, I wouldn't run these if your plan is abusive wheeling. I would run good, large heims and change them regularly. There is a reason why race rigs run them.

For the JF crowd, and the majority of people these are more than fine. If you are using them in a custom suspension, (like I am) you need to make sure the joint is neutral at ride height. They do not like to be misaligned all the time much like the stock clevite bushings.
 
#932 ·
LOL! I totally forgot about that. Even though they were not run as recommended, and he dropped 3-4 feet onto a boulder at the perfect location, that is no excuse for a broken weld in my book. Guess I have some hat eating in my future! :2thumbsup:

BTW, from a durability standpoint, we have had one 4500 (stock-mod) class EMC race rig running fully Duroflex joints for the entire season now plus 700 race prep miles before the season started. Their review so far has been outstanding!
 
#917 ·
Some interesting developments here. I am interested in seeing how that Synergy arm compares once it is released. It would seem to me that Metalcloak is on the right track when competition starts following and possibly building improvements on their products.
 
#919 ·
Weird that JK thread doesn't even mention Currie until Gerald brought it up.

WIth all of the questions of durability, I still don't know why one would need something different than the Currie joints. Maybe I'd have to run them if I ever get a streetish coiled Jeep again.
 
#920 ·
After reading Imped's reviews three or four times, I have gone ahead and ordered a full set of Metalcloaks aluminum control arms. Since my 3" lift, I've still been running most of the stock control arms. Off-road the ride has been decent and better then stock, but I'm most interested in improving it. I tend to drive a lot of miles on camping/wheeling trips, which I've got a 17 day trip to Utah at the end of the summer that will involve plenty of trails and dirt roads. I will also be towing a small trailer (link is in my signature).

I will not be doing the install. I have a small shop that I use (Imped, it's Sunfire), and although they're a Metalcloak dealer, they have not yet installed Metalcloak control arms so it will be new for them. I'll update this thread and see how it goes.
 
#921 ·
grogie, I am curious to hear how you compare the ride on the new arms to stock. I replaced my RC arms about 3 weeks ago in favor of the single-adjustable MC arms (also based heavily on Imped's reviews as well as many others) and am very happy with the way that it feels. It has been 4.5 years since I have rode on stock arms so while I honestly cannot remember entirely how it felt, this seems to be to be extremely close, if not the same. I can't wait to get off road to see how much better the Jeep feels there also.
 
#923 ·
Well, I assume my Bilstein 5100 shocks and the OME HD springs were the improvement in off-road ride that I immediately noticed after the lift, being that the Jeep just absorbed bumps better. Further improvement will be welcomed and I'll report it. Don't tell my wife by my upcoming Utah trip is just shy of 4,000 miles so that will be a good test run! :rofl:
 
#924 ·
Figured I would bump this with my initial review:

Install
Straight forward for the most part, but the instructions left a lot to be desired. I was able to figure out most things, but had to call Metalcloak on a few steps.
-The rear trac bar bracket reuses the stock bolt with the spacers to prevent crushing the mount.
-The control arms no longer require drilling out the mounts as they use factory sized hardware.
-Do not use the provided hardware for the upper arms as they stripped right before reaching factory torque specs. You can reuse the stockers.
-No torque specs are provided for anything. I was able to call metalcloak for their recommendations for the track bars and used the stock specs for the control arms.
-There are no bumpstop recommendations.
-Do not throw away your stock rear sway bar link hardware by accident like yours truly. Those bolts are expensive!
-One rear endlink had an incorrect bushing sleeve on one end. Metalcloak sent a replacement with the same issue. I was able to transfer the correct sleeve from one to replace the incorrect one and made one good link out of two out of spec links.
-Use antiseize on everything that is adjustable/removable (especially upper rear shock bolts)

The install went well other than the notes above. So well infact, I was able to get all four rear upper shock mount bolts out without a single broken fastener. Yeah I know you don't believe this, but it definitely happened. I replaced them all with new bolts and plenty of anti seize to hopefully continue the streak for the next removal.

First Drive
This went off without a hitch. I have an LJ with a BL/MML and didn't have any vibes at all. I will install my SYE when I do the TT. The Jeep drove and tracked extremely well. It also seemed smoother over broken surfaces which I attribute to the well matched OME shocks. Not rattles, clunks, or other noises.

First Few Hundred Miles
So far I have zero complaints. I drove into Boston a few times. The highways here are poor at best and the Jeep rode better than stock. It really absorbs impacts well. No more shudder when you hit a bunch of broken pavement like stock. It also corners better and more predictably now. This was a benefit I didn't expect. Overall ride quality is everything Metalcloak claims.

Offroad
I haven't had a chance to get off of the pavement yet. I will update this once I get on the trails.
 
#926 ·
Absolutely. There is no way to improve unless we know our weaknesses. I know you guys will get all the little stuff squared away. If it didn't come through in my last post, I just want to say this is an amazing company that makes amazing products.
 
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