Sources: www.acsbmx.com, www.bmxstunts.com, BMX Action april 1982, Bicross magazine, Go october 1990, ...
If you want to add any info, please contact buissonrouge@23mag.com.
ACS stands for American Cycle System

www.acsbmx.com: Before there was "dirt", "flatland", "vert, "street" there was ACS. Over 30 years ago aerospace engineers Charles Stephens and Robert Hanson founded ACS and developed, designed, and manufactured some of the first high-end BMX components. ACS alloy hubs ruled BMX in the 70's, and ACS mags were featured on popular selling bikes.

When freestyle started in the 80's, ACS pioneered  specialty components the pros needed like the ACS Rotor, RL Hub, 100psi tires, and BOA Brakes. ACS also designed and manufactured 5 models of skateboard trucks at that time, catering to all specialty disciplines. In the 1990's Keith Stephens joined his father and Robert at ACS. After being an early test rider for ACS, Keith rounded out his resume with several years experience in bicycle manufacturing and retailing.  
1975 Ad in Bicycle Motocross News may 1975.
1978 1978 ad
1982 ACS ad, BMX Action april 1982: ACS introduces the Stoker Stem and Stoker Seat Post Clamp. Both have new features that reinforce vital stress points. And there's no danger of ruining either part by stripping or breaking a bolt, because neither has internal threading in their melt forged alloy clamps. The seat post clamp bolt is secured with a steel sleeve. The stem has four clamp bolts held with high tension steel nuts. Other special features of the Stoker Stem are a 4130 chrome moly shaft and a knurled inner clamp surface to help prevent handlebar slippage. acs 82
1983 Ad in BMX Action february 1983: When Mike Buff flies off the ramp during a show he doesn't worry about his landing gear. He chooses ACS components because they're lightweight, durable and built for the demands of today's BMX action. Whether you're a pro or lust practicing, you'll find reliable and innovative equipment in the ACS lineup. Now available in 3 sizes, ACS Z RIMS' proven durability and resilience serve all your biking requirements. The new CANTILEVER BRAKE ADAPTERS AND LEVERS are a simple and inexpensive way to add stopping power to your bike. STOKER PEDALS are studded so that your feet can't slip on the parallelogram platforms, letting you concentrate on the big push. The ACS STEM'S inner knurling grips the handle bars, so you can grab and go with no slips. New Z HUBS with the small flange keep you rolling. STOKER SEAT, SEAT POST CLAMP AND SEAT POST let you sit down-lightly. For BMX excitement, the best part is ACS. acs 83
1984 ACS Z-RIMS.
Ad in BMX Action june 1984.
ACS ad, february 1985: Track or tricks? Up to now you had to flip tor it. Nylon mag wheels are great for freestyle but they sure weigh a lot. Alloy rims are super light - but you can't thrash them. ACS Z Rims are the answer. Super tough Z rims and matching Z hubs combine all the strength of solid mag wheels with the weight advantage of plain alloy rims. Now you don't have to chose between weight and strength- At the track, in the air or on the street, lightweight ACS Z Rims will never let you down. Thanks to the unbreakable DuPont Zytel material, ACS Z Rims are virtually indestructible. And that's a promise: ACS will replace Z Rims and other ACS components If broken during normal use. Send damaged part only for free replacement. ACS Z Rims are available in white, black, red, yellow and blue, individual rims or complete wheels with ACS Z Hubs - they're at your dealer now.
?: ACS Z-Wheels were a popular type of wheel for the professionals. All colors with matching hubs. There was a rumor that if you placed them in the Freezer they would straighten out. From the experiences of my friends this didn't really work. But they did make nice decorations to the pile of old broken bike parts in my garage. Unfortunately they faded away quickly. Brakes wouldn't work well with them.
www.mauricemeyer.com: ACS blew doors when they introduced a rim made of Duponts Zytel plastic. Able to take some flex and snap right back to true with some minimal spoke tightening from time to time, they made bent rims a thing of the past. The only drawback was that they lacked the braking ability of a chrome plated rim. Made eternally famous for the rumor that you could put them in the freezer and they would straighten on thier own.
acs z rims 85
RC Alderman - Z rims
A guy nobody has ever heard of, Dale Cooper, invents a little machined aluminum thing that attaches to your stem and allows for tangle free rearbrakes. ACS markets this as THE ROTOR.
Matt Beringer, www.facebook.com, january 2013: I was racing when rotors came out... I was 7 and amazed that people spun their bars without the cable gettin' tangled up. What cable? This was back in a time when bicycles had "brakes" and they used them for a thing called "freestyle"
www.mauricemeyer.com: ACS Potts mod and Rotor; This is the set up that changed freestyle forever. No more tangled cables! A clean design that was friendly to your knees, but without the upper bearing cup guide that was introduced later the lower cable tended to break alot. Access to the lower cables anchor point wasn't exactly convienent.

Steve Potts has come up with a new brainwave. It's a neat little button on the lever that you press down to keep the brake locked on. ACS are making a new lever incorporating the new idea.
acs rotor bmx 1985
Inspired and tested to its perfection by R.L. Osborn, The R.L. Edge is a completely new rear wheel with some very real and exclusive freestyle advantages. The unique R.L. Hub by ACS has a Newly Designed Anti-Backpedal Freewheel built right into it. So your pedals stay set, right where you left them, no matter how awesome your fakie or long your infinity roll. Plus the R.L. Hub uses Standard Suntour or Bendix Clip-On Sprockets that weigh less and come in more sizes than do regular freewheels. 48 Stainless Steel Spokes pair the hub to a very new and impressive R.L. Alloy Rim. Designed Concave not to be différent but to be Stronger than the rest. The R.L. Rim also features Special Spoke Nipple Seats to keep the spokes running tighter and lasting longer. You can buy the R.L. Hub or Rim separately but together they are THE R.L. EDGE, Freestyle Innovation that'Il keep you ahead of the compétition.

Bicross Magazine, janvier 1987: ACS vient de faire un grand bon pour l'humanité en créant une petite révolution technologique: le « free coaster » Explications: c'est le mixage d'un moyeu avec une roue libre et d'un rétropédalage. Il vous suffit de tourner un petit bouton grand comme un remontoir de montre pour changer une option à l'autre, et le tour est joué.
www.bmxstunts.com : ACS (Chuck Stephens and Dale Cooper) was inventing what was the first freecoaster hub. You could change your back hub from Freewheel to Coaster Brake in about 2 seconds. All you had to do was twist a little screw on the hub and it switched. Coaster for Flatland and Freewheel for ramps. The great thing about it was it gave you the ability to roll back without the pedals moving when set to the freewheel mode. This was a creative design, but extremely heavy. The hubs would not last long either for a typical rider.
acs rl edge
1987 45 STEM.
ACS came out with the ACS 45 stem. It angled down to compensate for the added height the Rotor added.Your stem was still raised up, but your bars were lowered. This was a great idea, but didn't last. Rotors became phased out with the polularity of the Gyro so there was no need for them. They were also weak. Many were breaking from doing simple flatland tricks.
www.mauricemeyer.com: ACS came out with a stem that was specifically designed to work in conjuction with the Rotor. A drilled hole through the clamping area provided a barrel adjuster to thread in and the Rotor cable to be routed out of the way from knees and shins. Endorsed by Brett Downs for it's strength, this stem started a production trend that lasted for years.

www.mauricemeyer.com: ACS took thier 36 hole wonder rim a step further and introduced the 48 spoke hole model soon after the first had proven it's sucess. More spokes = less flex. A brillant evolution with the original versions atvantages of lightweight and tweakable demeanor.
logo 1987
1988 R.L. TIRE.
ACS R.L. tire rated 100 psi. Higher pressure rating available at the time.

www.mauricemeyer.com: ACS updated the ever popular 45 stem and solved what became a problem with Rotor. The stem had to be raised considerably to allow the Rotor to operate correctly. This stem lowered the handlebars without losing the stem shaft height required to run the Rotor. Unfortunetly, these also became famous for the hairline cracks that would appear in the clamp bolt holes where the stem slants downwards.
1990 ACS BOA.
Ball bearing brakes.
ACS en arrêtera la production fin 1994.
Go october 1990: No slop. That's what ACS states on their press release about their Boa BMX/Freestyle model caliper brakes. Cold forged aluminium and loose ball bearings comprise the meat of these unique front and rear calipers, which are sealed to prevent unwanted foreign matter from creeping in. Available in silver or black at your favorite bike house.
acs boa bmx brakes
Ad in BMX Plus! april 1992: You Get Less With A Wedgelok. Less Adjustment. Less Hassle. Less Mess. One bolt does it in the new Wedgelok stem by ACS.
Unique twin-wedge construction offers a powerful mechanical advantage, so that one bolt takes the place of the traditional four. The result is a rigid grip on the handlebar, as well as a smooth top surface free of bolts and holes. The forged light ioy top section is supported by a down tube with hollow wedge bolt, both of Cro-Moly. The Wedgelok is adaptable to Rotors and other detanglers. When you're looking for a little more in a stem, ask for Wedgelok, the them with a little less.
American Cycle Systems, Post Office Box 2597, City of Industry, California 91746.
acs bmx stem 1992
1994 ACS have released a 48 hole coaster brake hub.
2004 ACS BMX is the new exclusive importer for Ares Bykes products for the USA and Canada. ACS will distribute a full line of ARES bicycles, frames and components for flatland freestyle. The first new products will be available in March 2004.

ACS and Ares agree that the flatland market is underserved in the USA. ACS will initiate new advertising for Ares in the USA and sponsor Terry Adams and Stephen Cerra.