Long Arm Kits Comparison

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Long Arm Kits Comparison

Postby djgaston » Tue Aug 27, 2013 12:36 am

One of the products DOR is most known for is our long arm kit, which has it's roots in the Dick Cepek long arms. When Extreme Suspension closed down, we sold the last remaining sets of long arms available and then we took over the design, making it better, stronger, and able to work in many new configurations.

There are several other long arm kits on the market, and many of them are very heavy duty and designed quite well. So I put together this comparison chart to give everyone a quick way to check out the specs on the top 5 long arm kits available for Ram trucks. Like I normally say, these are all un-biased facts. Please feel free to verify the info yourself if you feel inclined to do so. Yes I make a long arm kit, but I don't think you'll find that I'm being biased in any of the info posted. As one overweight sales guy on Cummins Forum said, "it's hardly unbiased when you make one of the products listed," but companies put together fact sheets like this all the time and this is my attempt at doing so because I have people ask me to compare different setups all the time. Before DOR was a business, I was doing this as a hobby, and I'm going to continue to provide factual info when I'm able to.

First, a small discussion on what long arms are. The stock control arms on our trucks are called short arms because they are just under 2' long from center to center. These arms connect the axle to the frame and are part of the suspension, but also play a role in your steering because they keep the axle square.

Short arms are fine for trucks at stock height, up to 3" of lift, but once you get beyond 3" of lift, the arms start to maintain an angle at ride height that promotes poor suspension and steering geometry. As the axle is pushed away from the frame (downward), the arms being a fixed-length will then pull the axle back towards the fender. This intensifies the more distance between the axle and frame. So with a small lift, you will not notice the axle pulling back at ride height, but it quickly pulls back as the suspension is cycled. This angle creates a harsh ride because of the wild angular change in the arms, and the poor axle positioning created by the short arms.

People put on long arms because they provide the truck with a much flatter angle on the arms, due to the increased length. This flatter angle helps to keep the axle moving straight up and down, instead of swinging forward and backward as the suspension cycles. I'll try to draw up some diagrams at a later date to help illustrate this movement. Long arms provide more suspension travel, in a flatter arc, therefore providing a better ride on the road and much-improved performance when off roading.

So why don't all trucks have long arms? Well, long arms aren't easy to fit under the truck, first of all. Until recently, you had to have at least 5" lift to clear long arms. You also have to remove the factory lower arm mount on all long arm kits that I am discussing in this thread. So there are permanent modifications to be made, they don't fit under all trucks, and also they are more expensive than short arms, due to the extra length and the new brackets.

There are two kinds of long arms, from a design standpoint. The first, and best, are true long arms, where both the upper and lower arm are much longer than the stock control arms. The other design is something that Skyjacker pioneered in the mid 90s which aren't really long arms, but they get called long arms because the lower arm is several feet long. However, the upper arm is the same length as stock. This setup, while allowing people to have the look of long arms without cutting up the truck or having issues fitting the longer upper arm, is not a real long arm setup. It is terrible geometry and creates a whole mess of problems with binding and suspension characteristics. Think of it this way - when the arms are not close to the same length, they do not share the same pivot points. When they don't pivot together, they bind. What you want is a free-moving suspension that isn't hampered by two arms trying to fight each other for axle positioning. You can only get this from a true long arm kit. You can also achieve similar results with radius arms, which I'll explain in just a second.

There are numerous kits where the lower arm is long and the upper arm is about the same length as stock. Some use the lower control arm mount for the upper arm, some use the factory upper control arm mount on the frame, and there are probably others that mount differently. I'm not discussing any of those kits because quite frankly they aren't worth discussing. It's a really poor design and they are all built basically the same, using thin tubing, cheap bushings, thin brackets. This is isn't something you really want under your truck from a performance standpoint. For looks, I guess they work fine. That's not what we do here.

So now onto radius arms. Radius arms are unique in that they look like long arms and they work like long arms, but they aren't long arms. A radius arm is one solid lower arm that goes from the frame to the axle, with a short upper arm attached to the lower arm, that mounts to the upper control arm mount on the axle. So the upper arm is completely dependent on the lower arm and it's mount. They share the same frame mount and they move together as one, since they are one arm. This design has been in use for decades, with mixed results. The radius arms of today are leaps and bounds better than they were even five years ago. The problem with radius arms is that the upper arm is fixed, as part of the lower arm, so the axle is not allowed to twist at all. It can only move up and down with the lower arm. As the suspension moves, the axle has a tendency to twist fore and aft - meaning the top of the axle wants to rotate forward and backward in relation to the lower half of the axle - but with radius arms, it cannot. The only exception here is the Carli radius arm, which uses a "plunger" shock to allow the axle to move on one side only, without letting it move too much by keeping the driver side stationary and using shock valving to control how much the passenger side can rotate. It's very innovative and honestly one of the smartest things that has been done for Ram suspensions, ever. That's so out of the box that it's something I would have expected NASA to come up with, rather than a suspension company. They effectively turned a rigid, restrictive radius arm into a moving thing that doesn't let the arm bind up the suspension. It's very cool. People that have their setup love it.

There is an age-old debate about long arms vs radius arms and which one is better. The bottom line is that long arms/4 link setups are better because they inherently allow more movement of the axle, they utilize more mounting hardware to secure the suspension, and they are stronger because of the load being spread out over a larger area and multiple mounting points. There is more "meat" to dual long arms than a radius arm as well - while radius arms tend to have a huge lower arm, the upper arms are usually very short and not built like the lower arms. With a long arm/4 link setup, the upper and lower are generally built to be very strong individually, and designed to work together. Most people who understand suspensions prefer a 4 link design when possible. The reason radius arms are used in the first place is because of the extra clearance provided by not having a long upper arm. If there was no issue with clearance around the upper arm, radius arm builders would be building long arms.

So, with all of that said, let's compare some long arm kits. I am including two radius arm setups as well since they are popular and in this case can achieve similar results as long arms. Not all radius arms are created equal - Carli and DT Pro Fab have excellent designs and are unlike other radius arm setups.

First, the DOR long arms:

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Next, the Thuren "alien" long arms:

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Pure Performance long arms:

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And now the Carli Radius arms:

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Finally, the DT Pro Fab radius arms:

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Conclusion:

Longest arms: DOR

Shortest arms: Thuren

Most travel available: DOR

Strongest brackets: DOR

Strongest upper arms: DOR

Strongest lower arms: Who knows - they are all insanely strong. Probably the Carli driver side arm, but then again it's entire assembly can go if one bolt fails, which is supporting twice the load as long arms. This is true on all radius arms.

Most options for ends: DOR

Most options for lift height, bends, etc: DOR

Best Price: DOR, even with our most expensive setup we are still below everyone else

Build time: Carli, DT, and Pure as long as you can find them in stock at a dealer.

Years in use: DOR, no other design has been around as long

Available for widest range of trucks: DOR and DT

Notes:

The only kit that requires body mount modifications with lifts below 6" is the DOR long arm kit. All kits require removal of the lower control arm mount. The DOR kit can be purchased with bends in the upper arm to compensate for the body mount, however it is still advised to notch the body mount to achieve full suspension compression on lifts below 5".

All mounts are single-hole mounts except the Thuren mounts, which utilize a honeycomb shape to provide some adjustment. While very unique and innovative, as it allows arm placement and pinion angle changes, it would be interesting to measure the distance between the holes to provide a baseline for how much strength is lost from this design.

The straight arms on the DOR kit can cause tire rubbing if the wheels have more than 5" backspacing, or really wide tires. We offer bent arms for tire clearance to compensate for those setups.

Pure Performance will bend their arms for tire clearance, however I have not seen where that is really necessary unless a person is running really high backspaced wheels, like factory wheels, with wide tires.

Like a lot of things online, there are always going to be people that support their brand and will try to convince everyone else to go with the same brand. What works for one person may not work for another. So I try to put this info out on the net for those who want to look at things objectively and make an educated decision based on facts, not on hype. If anyone wants to disagree with this info, ask them to provide facts, not their opinion. Honestly, you'll be very happy with any of the kits listed in this post. All of them have advantages and disadvantages. I think any of the manufacturers listed here would put their long arms or radius arms up against anybody else's, and hopefully that kind of comparison can happen one day (magazine editors, are you listening?). Until then, I believe this is the only in-depth resource anywhere on the internet that compares the various kits, with actual facts. Everyone has their own opinion, but I tried to leave mine out of this and look at it objectively. Please feel free to do your own fact-checking. :biggrin: I'll add to this as needed if specifications change. Info posted is accurate as of August 27th, 2013.
Danny Gaston, Dodge Off Road - sales@dodgeoffroad.com 855.9009.DOR

2014 Ram 2500 4x4 CTD
2005 Dodge Ram 2500 4x4 Power Wagon
2001.5 Dodge Ram 2500 4x4 V10
1998.5 Dodge Ram 2500 4x4 CTD 24 valve Work Truck - Future 6x6
1996 Dodge Ram 2500 4x4 V8 Project and Donor Vehicle
1995 Dodge Ram 2500 4x4 V10 Donor Vehicle and Parts Development Truck
2014 Tube Buggy with all-Dodge V10 drivetrain on Swampers and coilovers (in progress)
2013 Yamaha Rhino 700 Special Edition on Methods and Swampers

Previously:
2004.5 Dodge Ram 2500 4x4 CTD600
2001 Dodge Ram 1500 4x4 5.9 V8
1983 Jeep Scrambler
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Re: Long Arm Kits Comparison

Postby djgaston » Thu Aug 28, 2014 12:22 am

It's been a year since I originally put this post up, and some things have changed.

1) Our prices have not changed.
2) Other companies have raised their prices.
3) Synergy Suspension has a new long arm kit coming out in late 2014 that is worth checking out.
4) DOR is now stocking long arm brackets and building arms to order, so we're getting them out much faster.

I need to redo the spreadsheets above, but here is a brief side-by-side comparison. I am not including TGC, BDS, Fabtech, Pro Comp, Tuff Country, etc because they aren't in the same class. But one point I want to make is that you can get DOR's non adjustable long arms for about the same price as most of the cheaper non-adjustable setups from those companies. But I don't want this to be just about DOR - I just want to draw some parallels between all long arm kits so it's easy to see your options. The cookie cutter setups will always be popular because of the price and availability, so those are good options for people in that crowd that don't care about quality or performance. For those who are more interested in quality and performance, here is the list of 3rd and 4th gen long arm setups to check out. I didn't list as much info on the joints/bushings/adjustability but I did compare price, bracket and arm materials, and lift height options:

(If this is hard to read, right click on the image and select "open in new window" or just copy the image link and paste into a new window.)

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For 2nd gen long arm setups, I did a blog post recently that will help sort through that. It's more cut and dry than 3G/4G because we're really the only place making high quality kits for 2nd gens.

Blog post: http://dodgeoffroad.3dcartstores.com/Which-long-arms-are-best-for-your-2nd-gen-Dodge-Ram-_b_5.html
Danny Gaston, Dodge Off Road - sales@dodgeoffroad.com 855.9009.DOR

2014 Ram 2500 4x4 CTD
2005 Dodge Ram 2500 4x4 Power Wagon
2001.5 Dodge Ram 2500 4x4 V10
1998.5 Dodge Ram 2500 4x4 CTD 24 valve Work Truck - Future 6x6
1996 Dodge Ram 2500 4x4 V8 Project and Donor Vehicle
1995 Dodge Ram 2500 4x4 V10 Donor Vehicle and Parts Development Truck
2014 Tube Buggy with all-Dodge V10 drivetrain on Swampers and coilovers (in progress)
2013 Yamaha Rhino 700 Special Edition on Methods and Swampers

Previously:
2004.5 Dodge Ram 2500 4x4 CTD600
2001 Dodge Ram 1500 4x4 5.9 V8
1983 Jeep Scrambler
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djgaston
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Location: Lakeview, Arkansas

Re: Long Arm Kits Comparison

Postby djgaston » Wed Dec 16, 2015 2:11 am

Another thing to consider on 3rd and 4th gen long arm kits specifically is how short some of these "long arm" kits are. If you look at the brackets on the frame, Thuren and Synergy long arms are not that much longer than stock short arms. Check out the bracket location; you can use the body mount and transmission crossmember as a reference point since the pics were all taken at different angles. I'll use our 3rd gen frame here to get some better pics when time allows.

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Compared to our 3rd gen long arms:

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So why does this matter? Well, for a lot of people, it probably doesn't. But if you want a real long arm system with the most travel, it's pretty obvious that the longer the arms, the flatter they will stay as the suspension moves up and down, which means they don't bind up as fast and they don't pull the axle back as fast. It's the same arguments as short arms vs. long arms. Just in this case, it's mid arms vs. long arms.

Something else to consider. Notice how the Thuren and DOR lower arms have the joints hidden inside the bracket, where the Synergy lower arm and joint is hanging out. It's something to think about if you wheel your truck. The reason I wanted our lower joints inside the bracket is for rock crawling, so the joint is protected. My original brackets actually had that lower section of the bracket enclosed, but now the bottom is open. I figure if a rock can squeeze between the 2" OD tube and the 3.25" bracket opening, it's probably not big enough to do any real damage.
Danny Gaston, Dodge Off Road - sales@dodgeoffroad.com 855.9009.DOR

2014 Ram 2500 4x4 CTD
2005 Dodge Ram 2500 4x4 Power Wagon
2001.5 Dodge Ram 2500 4x4 V10
1998.5 Dodge Ram 2500 4x4 CTD 24 valve Work Truck - Future 6x6
1996 Dodge Ram 2500 4x4 V8 Project and Donor Vehicle
1995 Dodge Ram 2500 4x4 V10 Donor Vehicle and Parts Development Truck
2014 Tube Buggy with all-Dodge V10 drivetrain on Swampers and coilovers (in progress)
2013 Yamaha Rhino 700 Special Edition on Methods and Swampers

Previously:
2004.5 Dodge Ram 2500 4x4 CTD600
2001 Dodge Ram 1500 4x4 5.9 V8
1983 Jeep Scrambler
User avatar
djgaston
Admin
 
Posts: 3963
Joined: Sun Aug 31, 2008 6:25 pm
Location: Lakeview, Arkansas

Re: Long Arm Kits Comparison

Postby djgaston » Thu Jan 07, 2016 2:18 am

I just made this photo for a customer who has a really big lift on his truck, somewhere around 14". He has "long arms" on it now, but as you can see from the photo, they really aren't that long:

freitaslongarms2.jpg


Notice the placement of the lower arm in relation to the frame. That is where several other long arm kits mount. Here is why I refer to most of those are mid-length arms rather than long arms. You can see the red and orange lines are where the DOR long arms would line up on this truck and how much better the angles are, even at 14" lift:

freitaslongarms1.jpg
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Danny Gaston, Dodge Off Road - sales@dodgeoffroad.com 855.9009.DOR

2014 Ram 2500 4x4 CTD
2005 Dodge Ram 2500 4x4 Power Wagon
2001.5 Dodge Ram 2500 4x4 V10
1998.5 Dodge Ram 2500 4x4 CTD 24 valve Work Truck - Future 6x6
1996 Dodge Ram 2500 4x4 V8 Project and Donor Vehicle
1995 Dodge Ram 2500 4x4 V10 Donor Vehicle and Parts Development Truck
2014 Tube Buggy with all-Dodge V10 drivetrain on Swampers and coilovers (in progress)
2013 Yamaha Rhino 700 Special Edition on Methods and Swampers

Previously:
2004.5 Dodge Ram 2500 4x4 CTD600
2001 Dodge Ram 1500 4x4 5.9 V8
1983 Jeep Scrambler
User avatar
djgaston
Admin
 
Posts: 3963
Joined: Sun Aug 31, 2008 6:25 pm
Location: Lakeview, Arkansas


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