Falcon Forward Bite

So when you step on the gas and don’t really go anywhere, and the tires spin and make awesome slipping noises, throwing up gravel, smoke, and maybe the odd hypodermic from the side of the road, it basically means your suspension sucks.  Generally speaking, leaf springs suck; they twist in every direction possible, and do everything but actually try to make your vehicle move forward.  A suspension that works will plant the tires into the pavement, and shoot the car forward (grip, yes).

My first attempt at controlling this was the 5-leaf mid-eye spring.  It’s really pretty soft and doesn’t do shit for traction over a softer spring.  The next thing was the Panhard, which cancelled most lateral movement; this was definite progress, especially in terms of ramming my tires into the sides of the wheel wells and just losing lateral traction whenever possible.  In addition to this, I eventually added heavy duty shackles and Koni shocks.  These things did offer improvement, but it was really minimal under abusive dead-stop kind of situations (see autocross), or from low-speed corner launches.  I just spun, which is not so impressive after the eighth year of college…

After a bit of research, I came upon some circle track/stock car stuff, namely the pull bar.  This is what you do when you’re not allowed to commit to a real three-link (or four link, if that’s what you want).  The pull bar is like the top of a three-link, in that it’s one link bar that controls axle twist at the top of your axle housing.  When you go forward, the axle twist pulls on the bar; when you brake, it pushes.  It’s attached to the axle housing and a point forward in the chassis; for even more controlled control, you can make part of the link/bar a shock absorber, which adds a kind of timed release to the traction control.  I chose to use a biscuit bar, which contains a couple of polyurethane bushings (one push/one pull); it’s like old-school mountain bike suspension.

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There’s a lot to be said for adjustment relative to anti-squat (acceleration) and anti-dive (braking) that can be adjusted/tuned with the pull bar.  I installed the thing for a basic setting of about three degrees down; there are many points of adjustment front and back.  The rear mount is about 14 inches tall; I made it mostly out of a piece of 2×3 tubing I had lying around, in addition to some pieces of bracket I cut up (after ordering new).  The rear mount is welded directly to the top (almost center of the pumpkin, to the right) of my 8-inch (Ford) axle housing.

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The front mount was kind of blended into the main roll bar structure, beginning with a plate mount on top of the driveshaft tunnel (followed by the three round 1.25 or so inch tubes shown in the picture, plus a horizontal, which could theoretically be used for shoulder harnesses); for bike geeks, yes, I made the top part look like a stem/gooseneck, and there actually is a star-fangled nut in the top of the vertical tube for a cap (the paint is a combination of clear coat and black).

Overall, the set-up has been magical in terms of adding traction under both hard and part-throttle; it even works on a gravel road, going up hill (ask me how I know).  Eventually, it will probably become part of a legitimate three-link…

I can still spin the tires, but it’s way harder now.  Perhaps this will change a bit with the new X302…

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