School me on mid-arms

4speedhandler

4speedhandler

TJ Enthusiast
Joined
Apr 19, 2016
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Specifically I'm looking at the differences in both construction and real world performance associated with the Savvy and Rockmen kits.
To be as clear as possible i'm not currently shopping for a mid-arm i've actually been looking at a full johnny joint short arm setup but am curious as to anything i can learn about midarms just to have the knowledge. I've decided for sure i dont need or want long arms after much research but the midarm concept is intriguing especially with how little information i have found on them. So far i've seen a somewhat review thread on here and a basic explanation/shitposting thread on pirate. Can you guys all help out and enable me to gather pure information without opinions?
Custom midarm information may also be valuable though with my resources at the moment that approach may not be the most feasible.
 
We're fortunate to have @mrblaine here, he's the designer of Savvy's mid arm which has a sterling reputation. Blaine can probably do a quick compare of Savvy's vs. Rockmen.
 
The idea behind the mid-arm is that you make the arms only as long as they need to be and no further.

I have only experienced the Savvy mid-arm (at least for more than a ride along or two). But I can say that it works great so far. It doesn't bind up with my 14" of travel, it doesn't push the front end around, it pushes the front up and over and doesn't pop a wheely. I could go into a lot more detail and specifics of why and how but the short answer is that it works exactly as it should. I have it on both Jeeps (one installed exactly as the kit comes, the other modified slightly to package better with my build) and I don't see a reason to go with anything else.
 
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toximus said:
I could go into a lot more detail and specifics of why and how but the short answer is that it works exactly as it should.
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Please elaborate as much as you care to. I'm just looking to learn things and the more i can learn the better.
 
I believe there is another thread with very good info on this that @jjvw posted. Perhaps that’s the short arm versus long arm thread?
 
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Well all be damned. That Rokmen mid-arm looks almost identical to how Dave at Jeep West builds his. It doesn’t appear the rear is triangulated as it is with the Savvy.
 
Chris said:
Well all be damned. That Rokmen mid-arm looks almost identical to how Dave at Jeep West builds his. It doesn’t appear the rear is triangulated as it is with the Savvy.
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oddly enough its part of what intrigues me as it doesnt call for custom rear axle bracketry it seems. This is one of the reasons i am hoping to hear from blaine on the functional differences between it and the savvy system.
 
4speedhandler said:
oddly enough its part of what intrigues me as it doesnt call for custom rear axle bracketry it seems. This is one of the reasons i am hoping to hear from blaine on the functional differences between it and the savvy system.
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I’ve seen this type of mid-arm in action and it seems to perform very well. This is what Dave (MUDB8) builds his mid-arms like.

As to what the advantage of one versus the other is, only someone more knowledgeable like @mrblaine can answer that.

My understanding is that since this Rokmen style mid-arm doesn’t get rid of the rear track bar, it gives you more stability on-road, whereas the Savvy relies more on tuned shocks to gain more of that on-road stability.

However, I will say that my Savvy mid-arm drives exceptionally well on-road.
 
Chris said:
Well all be damned. That Rokmen mid-arm looks almost identical to how Dave at Jeep West builds his. It doesn’t appear the rear is triangulated as it is with the Savvy.
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Link?
 
I dont understand all the numbers for a link system but i have a buddy here that can explain it all to me decently. Does anyone have numbers for either of these to add to the tech side of the discussion? or if nobody has the proprietary 11 herbs and spices to either of these at least the percentage differences between them?
 
I haven't seen clear images of the Rokmen kit, but I believe they keep the upper factory arms. I am aware of one guy locally who has them and the rumors are not favorable.
 
jjvw said:
I haven't seen clear images of the Rokmen kit, but I believe they keep the upper factory arms. I am aware of one guy locally who has them and the rumors are not favorable.
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It says it comes with all new upper control arms as well as lowers, front and rear.
 
4speedhandler said:
oddly enough its part of what intrigues me as it doesnt call for custom rear axle bracketry it seems.
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The new brackets are all provided with the Savvy kit for the Dana 30, and/or 44. The installation requires very very little technical knowledge. Just measure and place brackets. It does require welding. If needed, you can find somebody in your area who does mobile welding and have them stop by after you have everything in place.

Chris said:
My understanding is that since this Rokmen style mid-arm doesn’t get rid of the rear track bar, it gives you more stability on-road, whereas the Savvy relies more on tuned shocks to gain more of that on-road stability.
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To understand the differences in linkages and geometry it's important to understand what effects what in the entire suspension system.

The antisway bar will be your biggest factor in on-road stability followed by the shock tune.

4speedhandler said:
Does anyone have numbers for either of these to add to the tech side of the discussion?
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When it comes down to it, the link calculator numbers are difficult to figure out for a physical Jeep and you're probably going to be unhappy with the numbers on paper. They're difficult to figure out because nobody installs the mid-arm on a stock Jeep — everyone's Jeep is different and weighted differently so publishing the number does no good for anyone. Even if you knew the numbers for your Jeep you'd be unhappy with them on paper because they're going to sound like they have bad values. Additionally, how do you know what values you want? For a highly purpose built rig such as high speed desert, mud truck, hill climbing buggy, etc) you might be able to design better geometry based on numbers, but that's not what most of us are doing.

For a Jeep it comes down to if the geometry works or it doesn't work.
 
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