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Suspension design concept, will this work?

Team_Jake said:
Good explanation. Adding to that, the purpose is to get decent travel (14"+) without chopping up the bed/cab or having the coilover axle mounts hang way down low. I'll work on an animation tomorrow.
Click to expand...
Okay now that I’m looking again, at full bump, what’s the distance from top of shock to top of lever?
I get that you’re getting 14” out of an 8” shock, but what’s the height from axle shock mount to highest point of the arm at bump? Really you’d only be gaining that distance from a packaging advantage, right?
 
Looks like some of the 90’s Suzuki full floater suspension. That worked pretty good, but always had to deal with friction in all the pivot points. Cool design though.
 
fl0w3n said:
Okay now that I’m looking again, at full bump, what’s the distance from top of shock to top of lever?
I get that you’re getting 14” out of an 8” shock, but what’s the height from axle shock mount to highest point of the arm at bump? Really you’d only be gaining that distance from a packaging advantage, right?
Click to expand...
Ideally the compressed length of the shock plus a bit for the arm. From a packaging aspect, mostly. Some advantage if you tie it to the sway bar. And maybe some in the mounting width.
 
total newb said:
Do you have anything showing you spring rate data?

Im having a hard time seeing how this thing doesnt just freely colaps without bananas high spring rates.
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I'm using a single 300lb/in spring on each coilover (it’s a 16in Eibach spring)

mobil1syn said:
lots of motion ratio, what dia shock you planning on?
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2.5"

fl0w3n said:
Okay now that I’m looking again, at full bump, what’s the distance from top of shock to top of lever?
I get that you’re getting 14” out of an 8” shock, but what’s the height from axle shock mount to highest point of the arm at bump? Really you’d only be gaining that distance from a packaging advantage, right?
Click to expand...
At full bump, the distance from the coilover axle mount to the highest pivot point on the pivot arm is 20.56". For reference, a 2.5x14 coilover at full bump (eyelet to eyelet) is 24.43", a difference of 3.87". Also keep in mind that at full articulation the tire starts to interfere with things, the top of a coilover on a traditional setup starts to interfere long before a pivot arm.
 
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I’m not gonna lie, it took me a minute to think and visualize this in my head.
I initially thought it would just bottom out with no resistance.
Now I’m understanding the link’s vertical movement compared to the coilover.
Build it!
 
Dude, get welding yesterday.

ThePanzerFuhrer said:
I would make sure that cross tube and the connection to the cantilever arm and arm themselves are massively overbuilt. Think semi trailer axle/hub strong.
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They don't see unsprung forces. They need to be srtong but not that strong. A pair of whatever fullsize truck unit bearings are kicking around would probably do great.

total newb said:
Do you have anything showing you spring rate data?

Im having a hard time seeing how this thing doesnt just freely colaps without bananas high spring rates.
Click to expand...
When you start stepping down into 9" and less coilovers crazy high spring rates start becoming availible off the shelf because you're getting into racecar sizes.

cervelorod said:
Looks like some of the 90’s Suzuki full floater suspension. That worked pretty good, but always had to deal with friction in all the pivot points. Cool design though.
Click to expand...
Link?
 
Other sporting types have been doing stuff like this for years. Get to building already.

One of my favorites:

www.speedhunters.com

Roadster Shop Does It Again - Speedhunters

In 2014 Roadster Shop debuted Rampage a track ready Camaro. Road Rage is cut from the same cloth, but built for both the street and track.
www.speedhunters.com www.speedhunters.com
 
HYDRODYNAMIC said:
One of the first things I looked at. Constant motion ration is easier to tune. The one that you were studying does not look constant which is hard to see from one picture but they probably have bypasses which can tune per zone.
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They don't.
They told me their shock guy hates bypasses.
 
What are the groups thought on using a splined unit bearing at the chassis as the pivot? The unit bearing mount flange / tube could be integrated into the chassis design. Arms could be fabricated to bolt on the the wheel pattern. Easily maintained.
Sway bar passes through the bearing to engage a drive flange ( or selectable lockout if disconnecting the sway bar is desired).
 
RustyC said:
What are the groups thought on using a splined unit bearing at the chassis as the pivot? The unit bearing mount flange / tube could be integrated into the chassis design. Arms could be fabricated to bolt on the the wheel pattern. Easily maintained.
Sway bar passes through the bearing to engage a drive flange ( or selectable lockout if disconnecting the sway bar is desired).
Click to expand...
you mean like this?

 
mobil1syn said:
you are asking a lot from a 2.5” coilover with a 1.8 motion ratio
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Do you think so? It's a smaller rig (3rd gen 4runner). I know next to nothing about shock tuning and just leave the guys at Accutune to make it work so I don't know if it really is asking too much on those coilovers.
 
Team_Jake said:
Do you think so? It's a smaller rig (3rd gen 4runner). I know next to nothing about shock tuning and just leave the guys at Accutune to make it work so I don't know if it really is asking too much on those coilovers.
Click to expand...

yes. 4Runners are heavy pigs
 
Team_Jake said:
IowaOffRoad

Here's an animation
Click to expand...
Neat!
Now, do one showing one side elevated with the other side drooping:flipoff2:

I'm guessing that the spring rates are going to have to be higher due to the extra leverage needed to act on the axle movement? Or am I missing something? Probably 50% or more than 'normal', by my eye...
 
Team_Jake said:
For the last year, I've been designing a cantilever suspension system for my rig. After a ton of research, conversations with pros, and a lot of tinkering in Solidworks, I had most of the details design out, but after seeing the Reulsport vehicle from the Sway Bar Tech thread a couple days ago, my brain has been really captivated by the concept. So I quickly modeled up my own design.

It's like an upside down mezzanine arm, with the coilover mounted upside-down, mounted to the axle instead of the frame. Running with this idea I drew up some things in Solidworks and came up with some pretty consistent motion ratios throughout the travel (min 0.50 and max 0.52), producing ~14.5" of travel from a 2.5x8 coilover. Loading wise, I ran a static simulation on the arm at full bump, made from 1/4" plates it has a factor of safety of 3.5, and it all packages really nicely in the wheel well. My question is, is there any reason why this conecpt couldn't work? Minus the Reulsport vehicle, I've never seen a cantilever / mezzanine style suspension with the coilover mounted to the axle instead of the frame.

The Reulsport Vehicle:
suspension-cantilever-1024x585.jpg


My Design, Ride Height:
BellCrankCapture1.PNG
BellCrankCapture2.PNG
BellCrankCapture3.PNG


Full Droop:
BellCrankCapture4.PNG


Full Bump:
BellCrankCapture5.PNG


Full Articulation:
BellCrankCapture6.PNG



Animation:

Click to expand...
DISCLOSURE
nOOB observation/question:

This suspension kind of looks like a tank suspension.

Can the bar going across be a torque arm, like a tank suspension?
Thereby eliminating the coil spring?🤷‍♂️🤔

My HMMWV trailer is set up this way.
 
IowaOffRoad said:
Neat!
Now, do one showing one side elevated with the other side drooping:flipoff2:

I'm guessing that the spring rates are going to have to be higher due to the extra leverage needed to act on the axle movement? Or am I missing something? Probably 50% or more than 'normal', by my eye...
Click to expand...

with his motion ratio the 300lb rate he mentioned is in line with what i would expect.

you will over work the shock
 
CDA 455 II said:
DISCLOSURE
nOOB observation/question:

This suspension kind of looks like a tank suspension.

Can the bar going across be a torque arm, like a tank suspension?
Thereby eliminating the coil spring?🤷‍♂️🤔

My HMMWV trailer is set up this way.
Click to expand...
Sounds like your're describing L-shaped torsion bars underneath the Plymouth Volare.
 
So what's the big advantage of this over just using trailing arms? Last build I did we used goat built trailing arms on a YJ to avoid the dumb leaned back shock deal. Not near the ratio you're getting, I got ~16" from a 12" shock.
 
YotaAtieToo said:
So what's the big advantage of this over just using trailing arms? Last build I did we used goat built trailing arms on a YJ to avoid the dumb leaned back shock deal. Not near the ratio you're getting, I got ~16" from a 12" shock.
Click to expand...
Read the thread.

Packaging.
 
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