'wittle 'wesistor (Mini Jeep)

[Functional Artist]

To temporarily attach (mock) a piece on to a frame (in this case the rear trailing arm mounting brackets)
...a "trick" I use, is to just drill a small hole thru the top of the piece (bracket)

Then, once the piece is "in place", mark & drill a hole thru the frame
...then, just use a small sheet metal screw to (temporarily) "screw" it down

Then, after "screwing" both brackets down
...& installing the rear trailing arm, I flipped the frame over
...& then, sat it in front of the FS drawing, to double check positioning

* Um...unscheduled surprise inspection
...but luckily, I think we "passed"

 

[Functional Artist]

The original plan was to use the Trailing Arm concept, for both the front & rear suspensions
...but, thinking it thru (with help) I now think Leading Arms would work better, for the front.

Leading Arms connect to the frame behind the wheel
...so, the "arms" "lead"

Whereas Trailing Arms connect to the frame in front of the wheel
...& so, they "trail"

What is the difference?
...or why does it matter?
...& why not just use standard A-Frames in the front?

Acceleration control, Braking control & it's a Jeep (faux solid axle)

Acceleration:
When accelerating, the kart kind of "drives" out from under "its" weight
...& that weight gets "pushed" toward the rear of the kart
...so, "if" using Trailing Arms, in the rear, that weight gets "dumped" onto the suspension
...which helps to "catch" & control that weight

Braking:
When braking, the kart kinda "stops" out from under "its" own weight
...& that weight gets "dumped" toward the front of the kart
...so, "if" using Leading Arms, in the front, that weight gets "dumped" onto the suspension
...which helps to "catch" & control that weight

Hope that made sense.
Leading Arms in the front, help with controlling the weight of the vehicle, while braking
...& Trailing Arms in the rear, help with controlling the weight of the vehicle, when accelerating

Here is an illustration of "braking action"
Notice how (while braking) with Leading Arms in the front,
...& using the arm connecting point as a fulcrum, the weight gets "dumped" on the front suspension
...& also, using the Trailing Arms connection point as a fulcrum, any weight (in the rear) would get "dumped" onto the mid-section of the vehicle

 

[Functional Artist]

Here is a pic of the frame with the Trailing Arm (temporarily) mounted to the rear of the frame
...& (2) Leading Arms (temporarily) mounted to the front

 

[madprofessor]

Looking forward to seeing how those leading arm spindles work out for clearance from the front tires and rims.............after being twisted to a good Ackermann setting. Looks like the mock-up has them pointing dead ahead for now.
Leading arms left a bad attitude in me after the fighting and the changes it took to get proper Ackermann without hitting the tires. Made me into a trailing arms fan forever. Opposite happens, trailing arms get further away from tires.

 

[Functional Artist]

Hey MadPro,
In the previous posts, I was discussing Control Arms as far as leading &/or trailing.
...but, yea I agree, it's easier to "deal with" spindles with "trailing arms" than "leading arms"
...&/also, "if" the steering was set up with leading arms, they would get in the way, of where I want to mount the coil-over shocks.

When I welded the Trailing Arm Brackets on I also, welded the front & rear "cross-members" on

They also, double as bumpers


Yes, Ima using "mock up" shocks until the ones I ordered arrive.

 

[Denny]

Did you ever consider using golf kart rear leaf springs?

 

[Functional Artist]

Did you ever consider using golf kart rear leaf springs?

Hey Denny,
Yup, I did
...but, I overruled the idea, in the name of creativity
...plus, the increased cost (4-springs & associated hardware)
...& then, there's the fact that the motor is to me mounted on/to the trailing arm

* You don't approve of my faux leaf spring-leading/trailing arm idea?

 

[Denny]

I approve, but that doesn’t matter. It’s your kart. I just figured the golf kart springs would make it easier and more realistic looking. And all golf kart motors and engines are sprung with the rear axle also.
Carry on.

 

[Functional Artist]

Hey Denny,

What I have in mind is a standard go kart (actually buggy) style trailing arm (just curved a bit)
...suspended with a couple of coil-over shocks

Kinda like this

 

[Functional Artist]

* The Wrangler (predecessor of the CJ) is one of the few remaining four-wheel-drive vehicles with solid front and rear axles.
These axles are known for their durability, strength, and articulation.
Another benefit of solid axle vehicles is they tend to be easier and cheaper to "lift" with aftermarket suspension systems.
This increases the distance between the axle and chassis of the vehicle.
By increasing this distance, larger tires can be installed, which will increase the ground clearance, allowing it to traverse even larger and more difficult obstacles.

In addition to higher ground clearance, many owners aim to increase suspension articulation or "flex" to give their Jeeps greatly improved off-road capabilities.
Good suspension articulation keeps all four wheels in contact with the ground and maintains traction.

With this in mind, I thought why not try & incorporate some "liftability" into the suspension system
...so, I made up some multi-hole (upper) shock mounting brackets
...with holes for "mock" screws (on the top side)

These (4) hole brackets, should give us (4) different height levels

So, it looks like "if" the shock is mounted in the top hole, the (standard) available suspension "travel" (from the rear of the trailing arm to the frame) seems to be ~3 1/2"

* Notice, the shock needed to be inverted, for clearance purposes

If the shock is mounted in then the second hole, it seems like it would have ~5 1/2" of available "travel"

If the shock is mounted in the third hole, it looks like were up to ~7" of available "travel"

...& "if"/when in the fourth hole, it looks like it would give us ~9" of available "travel"

** So, it looks like "if" we max-out the suspension (using these multi-hole brackets)
...it'll give us ~6" of extra lift

 

[madprofessor]

Finally. Someone using those little 100mm "shocks" that might be able to critique on them. I've got 3 of those in my ebay shopping cart for use in the rear as the short travel "flat track" version of my transformer kart. I'm holding off on 750# and 1500# units. What I need to know is if there actually is any dampening in them as a true shock absorber, or if they're just thick springs and nothing more. Whaddya know about 'em?

 

[Functional Artist]

OK, let's get back to the front suspension

I'm goin' to cut the Leading Arms in half
...so, they will "break" in the middle (right under the shock)
...& so, the front "end" will need to be able to "swing" (just like real leaf springs)

Something like this:

Here is the rear half of the Leading Arms (with brackets)
...(1) welded & (1) ready to be welded

I welded the end bracket on from the "inside", to keep the "backside" clean

...so, it can "double" as a "stop" for the rubber Leading Arm to Axle mounting bushings

Something like this:

With coil-over shocks

 

[Functional Artist]

Finally. Someone using those little 100mm "shocks" that might be able to critique on them. I've got 3 of those in my ebay shopping cart for use in the rear as the short travel "flat track" version of my transformer kart. I'm holding off on 750# and 1500# units. What I need to know is if there actually is any dampening in them as a true shock absorber, or if they're just thick springs and nothing more. Whaddya know about 'em?

Hey MadPro
I've used these little coil-over spring/shocks on many of my karts (Aerial Atom & Mini-Sling-Shot to name a few)
...but, 100mm is only ~4" from bolt to bolt

Here are the ones I usually use (like in the pic above)
...they are ~6" from bolt to bolt (~150mm)

It's labeled with a 750 In. Lbs. spring
...& yes, they seem to soften the ride
...& dampen the shock, of bumps in the road
https://www.ebay.com/itm/232747591888

There is a good visual example of this shock "in action", on my Aerial Atom kart, at ~8:55 (mark), in this video
...'til about the 9:20 (mark)
...where the camera "pans back" to the dash board
...& it shows the kart is going ~24MPH

 

[madprofessor]

Thanks for that heads up, F.A. Based on the vertical shake of the video, I've decided to go with the 750# shocks. Is that what you have on that kart? Pretty sure my kart's so much heavier that there will be some increased action on the shocks. Going into rapid build mode so I can sell it off and get the space in my shop back for the BareBallz build. Just have to finish up the little things, swap out the 212 for a 420, and do whatever it takes to get a TC on it. Videos will be forthcoming, my generic GoPro will wide angle it, but should still be good.

 

[Functional Artist]

Here is a pic of an older Jeep CJ5 (standard Ladder) frame, that I've been using, as a "reference guide"

Notice, one end of the front & rear "springs" connects to the frame using bushing

The other end connects using overconstrained joints (just learned that term)
...which are basically swinging "shackles"
...& are necessary because during spring flex (suspension travel) the spring gets longer

Also, notice the front springs are Leading, connected to the frame behind the wheels (with overconstrained joints in the front)
...& the rear springs are Trailing, connected in front of them (with overconstrained joints in the rear)

So, I needed a bushing holder, mounted on a perch, welded to the frame, right behind the front bumper
* I only welded around the tube, to help maintain a cleaner "look"

To make them, I cut the 1/2 hole out of each piece by first by clamping the (2) pieces of 1" square tube together
...& drilling a 1/4" "pilot hole" (in between them)

...then, I used a 1" hole saw to cut the hole out (yup, both at once)

After welding the bushing holders onto the bushing holder mounts
...I aligned 'em
...& then, got 'em welded onto the frame

* Everything is just tac'ed in place, for now

 

[Functional Artist]

I made the (2) front sections, of faux leaf springs, into "dog bones"

...& another view

 

[Functional Artist]

When I started designing this mini-Jeep, it was to have Dual-Trailing Arms
...& thus, only needing (4) bushings

Now, with design changes we need (10) bushings
...but, everyone is "out of "em" or "on have them on back order" of the stock ones (part # MJ-122122)

So, I had to upgrade to the heavier duty'er Red/Black ones (part # MJ-010323R)

JK, I made 'em out of some 1/2" ID rubber fuel line

 

[Functional Artist]

Made up a couple sets of overconstraining joints or "shackles"
...& then, started assembling the mini-Jeep faux leaf spring front suspension

Notice how the "shackles" swing forward, a little bit, as the suspension travels

* I had to remove the shock, to "take" this demo pic

 

[ezcome-ezgo]

I betting this thing will ride like a Cadillac.

 

[Functional Artist]

I betting this thing will ride like a Cadillac.

"Dang it Jim"
...back to the drawing board

Um...wait a minute
...wait, just a minute
...I guess riding like a Caddy isn't such a bad thing

OK, I'll deal with it