Help Your Muscle-Era Machine Handle The Corners With Detroit Speed A-Arms

10 min read

Help Your Muscle-Era Machine Handle The Corners With Detroit Speed A-Arms

10 min read

When you ponder aftermarket A-arms, is the biggest benefit a bit more overall strength or perhaps good old-fashioned cool looks? Maybe for some those are primary reasons to swap A-arms, but the reality is, not all A-arms are created equal. Some, such as the Detroit Speed examples shown here offer all sorts of other advantages. We’ll get into those advantages down the page, but first, let’s take a short trip back in time:

During the “musclecar era”, the stock front suspension hardware items that rolled off the Detroit assembly line were not (and some are still are not) exactly optimized for burning through corners, drag racing or other stressed performance applications. Sure the performance variants of those cars (for example, a SS396 or a GTO) usually came equipped with a front stabilizer bar, stiffer springs and perhaps revised shock absorber valving, but the basic vehicle architecture, including the A-arms was no different than the more pedestrian “family” members. Those vintage cars were typically manufactured with little caster. One reason for this was pretty simple: It allowed for easy steering at low speeds. This also meant Uncle Fred and Aunt Matilda could park their six-cylinder car easily without power steering. There was a pretty big trade off though: That same car isn’t exactly stable at high speeds (of course, Uncle Fred wasn’t going there anyway – and most likely, neither was Aunt Matilda).

Camber is another issue for vintage production line control arms: It changes dramatically as the front end goes through its travel (a good example is a drag car during a wheel stand). It doesn’t take a sage to see how goofy the front wheels look on some drag cars as they dangle in the air. With some of these combinations, as the car comes down to earth, the drama can unfold rather quickly. You can certainly feel it in the steering wheel, but more important, it manifests itself as hairline cracks on stock A-arms (been there, done that and we’re quite certain a few of you have witnessed it too).

In the days of old, the “fix” for the front suspension on a stock suspension door race car included cutting, pasting and otherwise tweaking the A-arms so that you could somehow find some much needed caster (which is the tilt of spindle) and at the same to reduce the camber change (as the suspension went through its travel) in the front end. Those “fixes” provided varying degrees of success, but none were perfect, simply because it wasn’t 100% possible when using modified A-arms.

But things have changed: You really don’t need to bend, slice and weld the front end components in order to mend the geometry. Today there are plenty of different a-arm examples out there. Some good. Some not so good. Fair enough, but were do you begin? When shopping for aftermarket A-arms, some companies build road race or “handling” style hardware while others, are dedicated to drag racing. Some, such as the Detroit Speed examples shown here work rather well in both applications. They’re incredibly strong, light, fit perfectly and they’re extremely easy to adjust. Paired off with Detroit Speed sway bars and coil overs (or better, together as part of Detroit Speed's Speed Kits), and dramatically improved handling and ride is as simple as a weekend spinning wrenches and a fresh alignment afterwards. This isn't just for cars that spend weekend after weekend racing around cones, either...even a daily driver can benefit from the broader range of suspension geometry that is offered by the Detroit Speed A-arms. There’s more too and we’ll get into that in detail in the accompanying photos. We’ll also show you the Detroit Speed A-arms installed, but for most cars, that’s as easy as removing and installing a few bolts. Check it out:

Detroit Speed A-arm photo 1

Each a-arm from Detroit Speed is carefully assembled in multiple fixtures and then TIG welded. Many aftermarket A-arms are constructed from mild steel, however some of the drag race only jobs are built from chrome moly (4130) steel. Some of the A-arms available have large diameter tubing and many are wire welded. By the way, thin wall chrome moly tubing doesn’t really work well when subjected to pot holes or curb rash. The laser-cut gussets and cross-braces increase strength and ride quality.

Detroit Speed A-Arm Photo 3

With welding operations finished the Detroit Speed A-arms are detailed and then high gloss black powder coated. Depending upon the application along with the configuration, you can cut 15 or so pounds off the nose of your car with tubular a-arm systems. Equally important, a good chunk of that weight loss is unsprung. That translates into a performance benefit because there is less mass for the spring to control.

Detroit Speed A-Arm positive caster

When an a-arm is constructed from scratch, it provides a company such as Detroit Speed the opportunity to design in more positive caster. Why is positive caster so important? It allows the car to track straight and true while at speed. Detroit Speed advises you should aim for 3-4-degrees of positive caster during the final wheel alignment process (by the way, these A-arms actually allow for a maximum of 6 or more-degrees of positive caster).

Detroit Speed A-Arm caster adjustment

Adjusting caster in the Detroit Speed upper A-arms for caster is simple. You remove the nut on the cross shaft stud and either flip or swap the caster tuner slug located in the billet cross shaft. The upper A-arms are provided with a pair of slug sets, allowing for a range of caster between (approximately) zero to 6 or more degrees. The shims you see are only used to set camber.

Detroit Speed A-Arm caster slugs

This is a set of caster slugs. It’s possible to reverse them (install with the hole forward or the hole backward), or you can use the second set for even more (or less) caster angle.

Detroit Speed A-Arm one-piece camber shims

(Photo: Detroit Speed) While the writer’s Nova uses stock style shims, Detroit Speed offers these uber-cool one piece camber shims. You can purchase them in three different thicknesses (1/16-inch, 1/8-inch, ¼-inch), either individually or in a kit.

Detroit Speed A-Arm camber issues

Here’s what happens when a car has camber issues. You see this all the time in NHRA Stock and Super Stock categories that mandate stock A-arms. Imagine what happens next (when the car comes back down to earth).

Detroit Speed A-Arm Delrin bushings

When it comes to replacement A-arms on today’s marketplace, most incorporate OEM-style attachment points to the frame. Some are fitted with OEM-style bushings. Other examples incorporate urethane bushings in one form or another. Some drag race examples make use of rod ends. Detroit Speed A-arms are manufactured with more sophisticated Delrin bushings, top and bottom (and they’re pre-installed). Note the zerk fitting...what you can't see are the CNC grooves built-in that allow the grease to travel the complete 360 degrees around the bushing. They’re included for all upper and lower A-arm bushing locations.

Detroit Speed A-Arm Delrin 2

Here’s another look at the Delrin bushings – this time on the bottom a-arm. The reason for using Delrin is because it eliminates “stiction” within the bushing. When you have “stiction”, the offending material (such as urethane) more or less freezes up the suspension component, rendering the shock (and more important, the shock adjustment) useless. Bottom line here is “stiction” isn’t helpful.

Detroit Speed A-Arm spring pocket layout

It’s possible to source aftermarket A-arms for three different spring formats – coil over and conventional springs along with hybrid tapered coil overs. Coil over setups allow you to play with ride height and offer plenty of spring tuning capability. This setup from Detroit Speed easily allows for either conventional springs or hybrid tapered coils.

Detroit Speed A-Arm coil fit

In this photo, you can see the car is in the process of being fitted with conventional coil springs. While a bit off topic, conventional springs provide for more suspension travel, which can prove beneficial in lowered powered street-strip cars.

Detroit Speed A-Arm steering stops

Steering stops such as these on the Detroit Speed A-arms are rather important. This is the point where the steering arm comes to a stop on the A-arm when the steering is at full lock.

Detroit Speed A-Arm ball joints

One criteria that should be really when shopping for A-arms the capability of being serviced in the field. A good example is if a ball joint goes bad (and all do eventually). How much trouble is it to replace? With the Detroit Speed setup, the bolt-in upper ball joint is a stock OEM piece. The same with the press-in lower ball joint. That means replacement components are as close as your local auto parts store. The ball joint pocket is CNC-milled steel.

Detroit Speed A-Arm suspension limiter

Note the suspension limiter. The limiter prevents the upper A-arm from crashing into frame rail at full suspension droop.

Detroit Speed A-Arm lower control arm bumper

Here’s the location for the lower control arm bumper on the Detroit Speed A-arm. A bumper is used to prevent the A-arm from contacting the frame at full lift. Since this lower A-arm is designed to fit a wide range of Camaros and Novas, the bumper can be positioned on the leading or the trailing end of the A-arm.

Detroit Speed A-Arm lower control arm bumper 2

The bumper is a simple device that screws into place. As noted earlier, the Detroit Speed A-arms are built with both leading and rear trailing bumper mounts, so they can fit early or late Novas and Camaros.

Detroit Speed A-Arm Upper Arm Installation

Detroit Speed A-arm installation for something like a Camaro, Nova, Chevelle (or other similar cars) is extremely simple once you have the old hardware off. The top end bolts directly to the cross shaft studs. Also note the pinned nyloc nuts on the CNC'd stainless steel cross shaft, one additional layer of safety provided.

Detroit Speed A-Arm Lower Installation

Downstairs, the Detroit Speed lower A-arm bolts on with a pair of bolts and nuts on each side. For many GM products, you’ll find the leading fastener goes on opposite to what you might believe is correct. The front bolt faces forward as shown here while the rear bolt faces toward the back of the car.


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