Cantilever VS Swing Arm VS 4 link

[7uptruckracer]

Can someone tell me the difference in design and application between the Cantilever and Swing arm or are they the same? Curious why no one uses a Cantilever? Just trying to brainstorm a way to be able to solve some of the issues with a 4 link. We all want a way to hike without excessive roll steer but also control indexing right? I mean isn't that what Rumley did? His device looks like a new school cantilever concept but now we can't separate the stuff

[Lizardracing]

Rules and packaging decide most of it however beyond that I don't think it really matters as long as you get the desired wheel loading on the track.

Cantilevers are more complicated and the mud and dust make all the moving parts require more maintenance.
Swing arms are always pushing the tire into the ground but lack the roll steer dynamics the floated four link offer.

Again, rules, packaging, ease of adjustment, over all dynamics of axle movement, front end design, driver preferences, etc all play a part into what most guys are running.

Running stuff on dirt is fun and invotive with in the means but in the overall grand scheme of technology its about 50 years old. The game changer I think is knowing how to apply what we now know and didn't then as far as math and geometries.
Live axles, carbs, 2 speed transmissions, etc....

[7uptruckracer]

Well can you explain how the cantilever is different from the swing arm? From what i saw the rumely device was like a cantilever but In idiots terms a cantilever escapes me right now. What are its goals as a design the 4 link I get completely and i understand its pros and cons. From what ive read the cantilever can give you interesting results in wheel loading as far as how it becomes progressive in its travel and how it used shock stroke compared to suspension travel, but what controls its the axles fore and aft movement?

[MasterSbilt_Racer]

Can someone tell me the difference in design and application between the Cantilever and Swing arm or are they the same? Curious why no one uses a Cantilever? Just trying to brainstorm a way to be able to solve some of the issues with a 4 link. We all want a way to hike without excessive roll steer but also control indexing right? I mean isn't that what Rumley did? His device looks like a new school cantilever concept but now we can't separate the stuff

The coilovers were parallel to the ground on the cantilever and partially a sprung mass.

[7uptruckracer]

How do you control roll steer?

[Lizardracing]

I think if you were to google it, you'll find there is about 100.000 different designs and the pictures will tell you everything.

[MasterSbilt_Racer]

I think if you were to google it, you'll find there is about 100.000 different designs and the pictures will tell you everything.

But, there are only two configurations that I know of ever being used on dirt late models

[Lizardracing]

Perhaps... but I read the OP wishing he understood the dynamics better and I was trying to make a point that a bizzilion different ways to accomplish it. Maybe i was off target.

I think if they were allowed by rules guys could come up with some wild looking stuff that worked.

[Stede Bonnet]

Canti-Levers Rock!

Well can you explain how the cantilever is different from the swing arm? From what i saw the rumely device was like a cantilever but In idiots terms a cantilever escapes me right now. What are its goals as a design the 4 link I get completely and i understand its pros and cons. From what ive read the cantilever can give you interesting results in wheel loading as far as how it becomes progressive in its travel and how it used shock stroke compared to suspension travel, but what controls its the axles fore and aft movement?

The cantilever is the predecessor to the swing arm. Canti-levers came in 2 types, forward & reverse. Most Rayburn's used what is known as forward cantilever. Imagine the lower arm on a swing arm car, but make it into a 90 degree forward facing triangle. Now instead of mounting the shock/spring on the swing arm running vertical to the ground, mount it at the top of the forward facing triangle running horizontal to ground and angle it down towards the frame rail, this is forward canti-lever. Custom Chassis, JigALo and some Rayburn's used reverse cantilever, same setup as above only the triangle is rearward facing and now mounted as the rear trailing arm, from the bottom of the birdcage. The shock/spring are still mounted at the top of the triangle only the shock/spring run to the back of the car and tend to be more horizontal instead of angling downward. Also Canti-levers aren't 50 years old, only about 30 and Randy Boggs won his World 100 with one and Clint Smith won his Hav-A-Tampa Championship with one in the early 90's. I have a friend who built a new one about 5 years ago and had good success with it before he retired. Your only limited by your imagination and the evil idiots at WRG/WoO.

Swing arm is the simplification of canti-lever. The Canti-lever designs on dirt cars were conceived by D!ck Anderson of Carrera Shocks, I have some of the early blueprints he gave me. The Rumley device may have incorporated some canti-lever aspects, but was a completely different suspension system and merely a modified 4 bar.

[old fan]

unified chassis rules for most sanctioned racing now , swing arm is on its way out

[Lizardracing]

Sucks too cause I think it's hard to beat a swing arm on the rough.

Fun Fact....Cantilever suspension used in cars started about 1910 on the horseless carriage made by the french.

[Stede Bonnet]

Sucks too cause I think it's hard to beat a swing arm on the rough.

Fun Fact....Cantilever suspension used in cars started about 1910 on the horseless carriage made by the french.

So was the "Mono-tube" shock.

unified chassis rules for most sanctioned racing now , swing arm is on its way out

I doubt that since only WoO has those rules and Lucas and many other series have opted NOT to adopt the, "Unified Rules". The unified rules also allow for swing arm, but you have to read it carefully.

[old fan]

Yes swing arm on older cars when was the last time a swing arm car ie rayburn win and that would be lucas woo ump and all its sub series mars mlra and if you are going to run the big races it will be one thoses sanctions

[LM14]

Cantilever we built in the late 90's. Worked great, just need to understand what is happening with them.

[old fan]

so was the "mono-tube" shock.i doubt that since only woo has those rules and lucas and many other series have opted not to adopt the, "unified rules". The unified rules also allow for swing arm, but you have to read it carefully.

world racing groups runs ump and its sub series mars is part of it and many guys run both mars mlra cornbelt aslso