New Motobilt 4-Link Suspension

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Cross-Threaded-06TJ said:
The black on red is a little aggressive on my eyes. Perhaps a white piece of paper and Crayon would/could be more visually appealing?







And no, I'm not bashing Motobilt's kit. I'm 100% sure that a Jeep with his kit, 43" stickies, king coil overs and super duty axles would be rather potent off road.
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Giant tires and a long wheelbase do cover up a lot of sins. 😉
 
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Mrholland said:
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With regards to crawling, is there really a difference in 3in of up travel vs 6in and upsetting the attitude of the rig when the obstacles are large enough the stuff the tires?
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Yes. Do the math and you can start to see what the difference is before the frame gets shoved up by the compressed shock. It has everything to do with stability and controlling movements.

But I have no conception of how to build a rig, so please disregard. 🤣
 
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Bender said:
The yj build is more of full bodied low slung bouncer for lack of a better description. As with any full bodied build, the frame and axle clearance is one of the biggest factors. Getting the frame rails as high as possible over the axles allows the whole body engine/trannyt/case to sit lower given the same up travel . We used our front and rear frame kit to not only achieve more clearance over the axle but it also is narrower than the stock frame to allow for more shock clearance throughout the suspension cycle. A double triangulated suspension was used because it travels more linear with less suspension over steer. It also allows for much more tire to link clearance when turning.
Because it is going to be beat on pretty aggressively all suspension joints are 1 1/4. They mount to 4” tubed 14 bolt axles front and rear. The weight of these axle is considerably heavier than say a 10” fabricated housing. With this build unsprung weight isnt as big of an issue as would be say in an ultra4 car where you would want a different spring unsprung bias.
We stretched the wheelbase to help with approach and departure angles and climbs.
A lower “sub frame” I’d you will not only allows you to get more vertical separation at the chassis, it allows you to do it without having to cut the tub or run a body lift. Having the “subframe” gives you a couple more valuable inches of clearance to run exhaust and drivetrain components.
We are running full hydraulic steering because of its strength and because steering input isn’t transferred through the mechanical linkage to the chassis.
The floor under the seats was cut out the lower the seats in the tub which allowed us to make a 3” lower cage while retaining the same head clearance. I only mentioned this because it ties back to the lower CG of the build.
This rig will most likely end with 6-7” of up travel as it’s the best balance of crawl/trail use. If it we’re getting beat on it would be more around around 8” and in crawling it would be set around 4” to lower the center of gravity.
This rig is running a 742 hp 454, t400/ atlas combo. Big hp for hills, big burnouts and who doesn’t like hp!
The kit has a skid plate as well as a removable tubular substructure for strength. This isn’t a little bracket you weld to the side of your frame, it’s a complete heavy duty structure that ties both frame rails together and is welded in.
The front crossmember of the kit is removable as well as the skid and tubular bracing to ease of maintenance. We’ve also included brackets that bolt in place when the front crossmember/lower link mount is removed so you can temporarily bolt the chassis side lower to so the vehicle can be moved (which really helps with small shop spaces)
Let’s see.. the front section of the skid comes with a removable front section so that an engine skid plate can be installed and still has secure mounting location as well as a smooth engine skid/belly skid transition.
It has a 20 gallon cell that is mounted behind the axle which gives you the ability to run a rear seat and ice chest/gear. Because when it comes down to it, it’s not a comp rig and will see mostly extreme trail use.

With all this said, the only reason I’m here is because someone made the comment that I didn’t know what I’m doing. I came on to ask how he came to this conclusion, not to sell this kit.
MOST IMPORTANTLY!
I will not and have not disparaged Savvy, Blaine or his experience or expertise. He clearly knows his shit and has proven it time and time again. I’m not sure if most of you realize just how small this industry is and how most players know each other.
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454 and14b f/r! Any videos of this beast in action??
 
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starkey480 said:
That’s my friends buggy with 116” wb, 20” belly height, 40s but the specifics don’t matter. The point being that a low belly can hang you up and can be a disadvantage.
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Agreed, but at some point doesn't line selection come into play? Could that have been avoided entirely if line selection was more of a priority? And I understand sometimes a tire slips and the line you chose is no longer your choice
 
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Fouledplugs said:
Agreed, but at some point doesn't line selection come into play? Could that have been avoided entirely if line selection was more of a priority? And I understand sometimes a tire slips and the line you chose is no longer your choice
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My thoughts too. Also to add, the control arms will also help a little to prevent the shovel from a direct forward impact...
 
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Chris said:
Could you make it any more clear? It seems that many in this thread are having trouble with this very simple concept :LOL:
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Same for pro rock crawlers and some ultra4 guys. Bunch of idiots…right?:ROFLMAO:

Devils advocate here, lets not forget, no matter how well it’s built on paper, the driver behind the wheel makes it to the finish line, hangy down bits, antiquated suspension, and all. Nice example, Jesse Haines at KoH last year won on leaf spring under the axle.

Anyone here could have the best numbers and best performing rig when it comes to suspension, a good driver with a sub par rig on paper will outperform them every time.
 
Fouledplugs said:
@Bender
You mentioned earlier in the thread that using a flat belly and link mounts mounted high carries a disadvantage…at least, that was my impression. Obviously the new MB link kit uses a stock YJ/TJ/LJ skid location to mount the links and it carries an advantage, could you elaborate on that a little bit?

No one seemed to debate this and it seems that this thread centers around this idea of a flat belly being the end all be all. I’ve noticed a lot of the Ultra4 guys and W.E. Rock competitors dont have flat bellys as
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Fouledplugs said:
@Bender
You mentioned earlier in the thread that using a flat belly and link mounts mounted high carries a disadvantage…at least, that was my impression. Obviously the new MB link kit uses a stock YJ/TJ/LJ skid location to mount the links and it carries an advantage, could you elaborate on that a little bit?

No one seemed to debate this and it seems that this thread centers around this idea of a flat belly being the end all be all. I’ve noticed a lot of the Ultra4 guys and W.E. Rock competitors dont have flat bellys as well.

Anyone?
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It has been covered a few times in this thread. Vertical separation at the chassis.
starkey480 said:
View attachment 362665
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starkey480 said:
View attachment 362665
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Look back through the post and you’ll see that I’ve posted my own simple drawings to show where yours is flawed. Please show me where the “shovel” is. From the end view the belly is in fact much narrower even.

217BAF1F-22E4-479B-9D91-2A536B886EE9.jpeg


66D8649F-D414-4C9C-83CD-0C9E6382545C.jpeg
 
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Fouledplugs said:
Would you explain how big tires and long wheelbase covers up a bad build?
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Bigger tires bridge up and over obstacles more effectively than smaller tires do. Longer wheelbases create more stability than a shorter wheelbase. I know you know these things.
 
jjvw said:
Bigger tires bridge up and over obstacles more effectively than smaller tires do. Longer wheelbases create more stability than a shorter wheelbase. I know you know these things.
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Yes correct, I know these things. But I’m wondering, all things being equal, the flaws would show themselves at an obstacle that calls for big tires like 42’s and a long wheelbase like 115”, correct? You’re saying that’s when the flaws show themselves.

I highly doubt an LJ on 37’s is going to be capable of hanging with trails where a 42” is required? Or am I wrong?

At some point both short and long wheelbases are gonna be faced with bellying out. Line selection and driver’s skill becomes paramount at that point.
 
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Bender said:
The point i think you are still missing is that’s both are technically a ‘flat belly”. Both transition smoothly from the links to the Belly.
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That was my point. Not an expert, have seen tons of W.E. rock guys and Ultra4 guys get through even the toughest obstacles with a belly that hung down. Like you said, they are flat and smooth.

And I get it, a flat belly gives more ground clearance and can see the problem is solved by tucking it flat. But is it worth solving for the sake of bragging rights when in the rocks? Or does it actually equate to real world performance that’s measurable?

I would like to learn how the high belly, body lift, high mounted links, and the lack of separation between the axles and frame would been seen and felt when in the rocks.

Answering that prob answers what advantage separation between the axles and frame makes in the rocks too.
 
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Bender said:
The point i think you are still missing is that’s both are technically a ‘flat belly”. Both transition smoothly from the links to the Belly.
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Now you're just being silly. Do you also want to redefine breakover angle?
 
Fouledplugs said:
42” is required
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No trails "require" a certain size tire, only event organizers do. Watch the documentary Kingdom Krawl, most of the guys on that show run >40's, but there have been a few running 35's. Yes, they may need more spotting, and picking a perfect line for the rig, but they can and do the same trails as the huge tire guys.
 
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rasband said:
Now you're just being silly. Do you also want to redefine breakover angle?
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How is that being silly? Silly would be raising the belly only to be forced to raise the body therefore increasing both link angle and CG. The answers are in plain site and only an google search away. Look up unlimited competition rock crawlers and look though those pics. look closely at what works and why. You have fixated on belly height and break over angles when that’s is only one small piece of the overall build design.
 
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