The cure for coil-spring envy...
For those of us with leaf spring suspensions, the Teraflex Revolver shackle presents an easy-to-install cure for coil spring envy. Invented by Curt Hildebrand of Metal Made Rite, the Revolver was a technically successful product from the start but it never saw widespread adoption until Metal Made Rite partnered with TeraFlex Manufacturing Inc. TeraFlex was already a well-established 4x4 products manufacturer and able to take advantage of their size and experience to introduce economies of scale that greatly reduced the price of the Revolver Shackle. The result is an affordable product that can be used on virtually any leaf-sprung vehicle which needs an improvement in suspension flex.
As you can see in the photos, the Revolver Shackle differs from regular shackles in two main aspects:
- It incorporates a hinge to allow it to open and close depending on the terrain.
- It also includes a swivel point which allows the spring to twist when needed.
These two simple changes provide a substantial gain in suspension flex that can easily be measured on the ramp and, more importantly, on the trail.
Why are the Revolvers hinged in the longitudinal axis?
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To allow the springs to twist during compression. Besides improving the flex,
it allows relieves stress on the springs, thereby improving their lifespan.
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Installation
Installing the Revolver Shackles was dead easy. For each shackle, you remove two bolts, remove the old shackle, install the Revolver Shackle, and re-install the bolts. Do this four times and you're done. Total time: under an hour, easily. Do it on your lunch hour if you want. I'd love to write more about the install but there's nothing else too dead. It's that easy. Really!
Results
After the Revolvers were installed on Project YJ, I went for a drive on the street and highway and I noticed no difference in handling. The Jeep rode the same as it always had. Cornering around intersections and freeway on-ramps and off-ramps yielded no surprises. Rapid stops didn't result in the shackles opening up.
The first opportunity for off-road testing was the 2002 Island Rock Crawl event. It showcases western Canada's best technical 4x4 trails and would be the perfect venue for testing the Revolvers. I had driven the trails in previous years so I would have a benchmark of experience against which to compare.
As with the city driving, driving on logging roads on the way to the real trails revealed no differences in vehicle handling. But once we locked in the hubs and hit the trail sections where low-range and a spotter were required, that's when I began to notice that the Revolvers made a difference. Project YJ consistently ramped around 1015 on a 20 degree ramp. That's par for the course for a spring-over YJ using soft springs and it's enough flex that lifting a tire is an infrequent occurrence BUT it does still happen. What I noticed with the Revolvers is that those occurrences dropped by a noticeable amount. On obstacles where past experience told me to expect that slow see-sawing motion that is indicative of a lifting wheel, nothing happened. All four wheels stayed on the ground and the Jeep's stability remained constant. In short, Project YJ's performance envelope had been expanded.
If you look at how the Revolvers work, it makes sense that they would noticeably improve suspension flex. And with improved suspension flex, you will get improved trail performance. So, to be perfectly candid, the improved ability of my Jeep's suspension wasn't a surprise to me. The Revolvers worked as advertised.
Will Revolvers make my 4x4 less stable?
Hah! Not a chance. I had absolutely no bad experiences on all manner of steep drop-offs, climbs, and side hills.
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I drove the same trails with the Revolvers that I used to drive without the Revolvers.
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The only difference I noticed was that, with the Revolvers, the Jeep was better able
to keep all four tires on the ground.
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What was a surprise was the fact that they didn't negatively impact off-road performance. Why? Because many web 'wheelers (those guys who seem to spend more time talking about 'wheeling than actually hitting the trail) say that the Revolvers would suddenly "unload your suspension" and destabilize the vehicle. Typically, these doomsday scenarios involve side hills or steep climbs or descents. You know...trails just like they have at Rock Crawl! Well, I'm sorry for letting down your carnage hounds but there was no "sudden unloading" and no catastrophic rollovers or endo's. If anything, the Revolvers made Project YJ more stable. I did all the same crazy side hills and drop-offs as in previous years. No worries at all. Wait, that's not true. This year, I did one trail that I'd never done before: Hell's Gate. For anyone familiar with the Morning Side Tough Truck competition, they can tell you how terrifying that hill is. It's steep, rocky, and includes a turn right at the steepest section. Basically, it's the nastiest downhill on Garibaldi Mountain and I drove it with the Revolvers. Take my word for it, the Revolvers do NOT hurt your vehicle's stability.
Ramp Scores
Any discussion of suspension flex invariably turns to the topic of ramp scores. While not an accurate indicator of a suspension's off-road performance, it is a useful tool for before/after comparisons, as well as identifying those factors that are limiting your suspension's flex.
Flexing with my old (short) shocks.
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Wheel travel was nicely balanced between front and rear. This may not make a difference on the ramp but it is critical for stability on the trail.
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With the shocks attached, this is how much the rear Revolver opened up.
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With the shocks disconnected, look at how much more it opens up. To realize the full potential of Revolvers, you will need longer shocks.
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Ever since the spring-over-axle conversion, Project YJ has consistently ramped around 1015 on a 20 degree ramp. Installing the Revolvers immediately raised that to 1138, a 12% increase. It was a nice gain but it looked like the shocks were limiting the droop. Disconnecting the shocks yielded a score of 1234, an increase of 21%. At this point, fender edge clearance, plus the fact that the rear tire was hitting the inner fender wall appeared to limit the axle movement. I've always said that when Project YJ reached an RTI of 1300 on a 20 degree ramp, I would stop working on the suspension. With the installation of some new shocks and relocated shocks mounts, plus an adjustment of the spring perches, that goal will be reached. Frankly, I'm very pleased that I can reach that point with what is essentially a very simple and easy to maintain suspension system. The Revolvers are a big part of that.
Conclusion
Got a leaf springs on your 4x4 and want to maximize your flex? Then buy a set of Revolvers!
Applications
Besides Jeep YJs, Revolvers are available for these other vehicles:
- Jeep CJ ('41-'75)
- Jeep CJ ('76-'86)
- Jeep XJ (Cherokee)
- Toyota FJ40 & FJ45
- Toyota pickup and 4Runner
If you're interested in a set of Revolvers but if you don't see your vehicle listed, give Teraflex a call. One of the existing Revolver models might just fit your application.
...lars
