     
Adjustable Control Arms Our adjustable front control arms, shown here with rod ends and ball joints...
...and here is a lower control arm, mounted on a late CMC chassis. For some reason, I left the AN6 bolt out of the photo, the bolt which holds the rear arm to the forward arm. That bolt is included with the control arm assemblies or kits (as are its washers and nylock nut), as is similar hardware in the upper control arms, though rod ends and ball joints are not--we offer rod ends in a variety of styles, and ball joints to fit a variety of spindles. Note the 1/8" hole in the shock mount bracket above. Also note that the shock mount bracket isn't yet welded in place. Since there is quite a bit of variety in shock installations, we leave welding that bracket to you. To make that job easier, once you've decided where the bracket should be, use that hole as a guide to drill a 1/8" (or #30) hole through the plate and pop rivet the bracket in place. If you decided wrong, it's a heck of a lot easier to replace a pop rivet than a weld. Once you're sure it's where you want it, weld the bracket and remove the rivet. We also offer these control arms as a weld-it-yourself kit; they're 25 bucks off per control arm so that'll save you $100 on the complete set of four (two upper, two lower). With these kits, the steel tubes come longer than you need--you trim them to your own specs and weld in the bungs, plates and tabs. And for folks who would like to fabricate these parts themselves, we have a page full of front suspension drawings. Here's what comes in an upper control arm kit...
...except you may want us to send that swaged aluminum radius arm (the tube on the right side of the photo) in a second shipment, so you can do some test fitting first with our New Improved PVC Suspension Simulator.
What's improved about this simulator? For one thing, it's so cheap for us to make that we throw it in free when you buy two upper control arm kits...and presuming your car has two sides, you'll want two control arms, right? The simulator is two PVC tubes; a long tube with 1/2-20L threads in one end and a shorter tube with 1/2-20L threads in one end and 1/2-20R threads in the other. After you've welded the clevis mount tab to the bung, you can use the long PVC tube in place of the 3/4" steel tube (wrap tape or paper around the PVC first 'cause it isn't a full 3/4" in diameter) and cut the unthreaded end to fit. You can cut both ends of the short tube to simulate the radius arm in the length you need--and once you're done test fitting with the PVC bits, tell us what length you want and we'll get your pair of aluminum radius arms out to you. These radius arms come in 1/2" increments, but they can be trimmed up to 1/2" on each end once you've got them. There's a $5 charge for sending the radius arms in a second shipment, but it'll save you time and money compared to ordering the wrong size and sending them back and ordering another set. Read the front suspension drawings before you start welding the parts together. The following installation photos are courtesy of Nathan Engdahl, from his Miata-based build log on LocostUSA.com. His car has a number of interesting innovations, but all we're going to look at here is the front suspension.
The upper front shock mounts are on a tube that doesn't exist in The Book. It's a good addition for a couple of reasons. It extends the shock upper attachment point outward, which makes the angle of the shock (in reference to the lower control arm) less acute, and allows the lower shock bracket to be placed closer to the lower ball joint.
Why are these Good Things? Because they both increase the amount of shock travel relative to wheel travel (which improves damping and allows a lower spring rate) and because moving the lower shoch mount outboard reduces the beam load on the lower control arm. If you cruise the suspension strings on Locos forums, you'll find a number of cars with front lower shock mounts further inboard than these, with the control arms bent at the shock mount point. You don't want that.
Another benefit of mounting the upper shock mounts on a seperate tube is, you can do a lot of adjusting and experimenting before you commit to welding the tube to the frame. In fact, you don't ever have to commit to welding them to the frame--you can make that tube a bolt-in, which gives you the option of changing shock geometry when and if you change shocks.
Here's an example. Nate moved his upper shock mounts inboard from his first guess, to soften the suspension a bit. He's using QA-1 large body shocks (I don't know the spring diameter but it's significantly bigger than the usual GAZ shocks we see on most Locosts). they're still more than an inch outboard of the 'book'l bracket-under-the-frame-rail upper shock mount.
A further benefit is, by tying the shock upper ends together and thus attaching each shock to both upper frame rails, frame flex is reduced. This, too, is a Good Thing.
You may have noted that Nathan's chassis doesn't use standard suspension brackets. These two piece angle brackets were developed to deal with a rare but challenging problem. Sometimes frames are built to the book, with intent to use bushings at the suspension pickup points, but before the brackets are welded on, the builder decides that rod end control arms are the better way to go. 'Scuse me if I've mentioned this before, but rod ends are much stiffer and stronger if loaded radially than axially (typically 7 to 10 times stronger) so it's good to avoid side loads when you can. Nowadays, most US-made Locosts have the suspension mounting tubes (LA and B, FU1 and 2) angled to face the rod ends, but if yours was made without that feature, these two piece brackets will angle the mounting bolt for alignment with the rod end, with no need for high misalignment washers. The dark side(s) of the brackets are 1) The have to be accurately aligned or the 1/2" bolt won't go through them. The easy way to align them is, bolt a rod end (with spacers/washers) between them before tacking them to the chassis. Note we put a 1/8" alignment hole in them (as we do on the lower shock mount brackets; see commentary near the top of this page) to further simplify the task. 2) They cost more to make than the standard suspension brackets. They're laser cut, since we don't have the quantities necessary to make punching them practical, and they require their own bending fixture and there are twice as many parts to bend. Bottom line is, they're about 50% pricier than the one piece bracket. (re dark side #1: there was some discussion of this on LocostUSA.com, with one guy saying these brackets "...look like a nightmare to install." Dave Hempy, who used these brackets in his build, responded... "The two-piece brackets are no trouble to install. Just stack the two sides, two spacers and the rod end together, then bolt the assembly solid. Carry that whole assembly over to the car, side it on the chassis tube, and it will pretty much hold itself in place. Add a C-clamp when you get it where you want it and tack weld. No problem. Possibly easier than a regular bracket, since it is easy to clamp in place with a rod end in place." Sounds good to me.
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