AST 5100 Monotube Coilover Struts and Shocks BMW E46 M3
The 5000 Series damper stands as AST's full race setup. It is available in one, two and three way adjustments. 5000 Series coilovers are fully streetable but utilize the full race components like inverted struts, teflon flat bearings and spherical bearing mounts. 5000 Series coilovers are great for competitors with points based rules or rule-free damper requirements. The 5100 gives the customer the ability to have the highest end components without running reservoirs. 5200 models use remote reservoirs or "piggyback" reservoirs to control low speed compression. 5300 models use remote reservoirs or "piggyback" reservoirs to control low and high speed compression.
One key feature on the 5000 series shocks is modularity, which makes them easily upgradeable. This provides an upgrade path for customers on a tight budget that want an adjustable, high performance, race-ready shock but can't quite afford the double adjustable 5200 or triple adjustable 5300. Simply purchase 5100s, and when you're ready, send your ASTs to an authorized rebuild center to upgrade them to 5200s or 5300s with remote reservoirs. Rest easy knowing that your shock absorber investment will perform today and in the future, as your budget and needs grow.Parts Included in the basic AST 5000 kit:
Also note: the rear shock in this kit is made to work with a spring in the OEM location ("true coilover" rear shock conversion kits are available for BMWs on all 5000 series rear shocks, which come with externally threaded aluminum rear shock bodies). Please call for more details.
REAR SHOCK MOUNTS : Optional Rear Shock Mounts include AST-USA Spherical design or Heavy Duty rubber E46 M3 style. We recommend the spherical RSMs for most users that see any competition use, such as autocross or track events. If the car is a daily driven vehicle only and/or the user is worried about bad roads and any additional NVH transmitted through a rear spherical mount, then choose the HD rubber style instead. Our HD rubber RSMs will be machined to fit the 12mm rear pins on the current 4100s and the 4150s at no additional charge. The advantage to spherical RSMs is their ability to transmit reactions to shock forces instantly and direct - something that shows up on a shock dyno plot.
RSM REINFORCEMENT KIT : Many BMW models are prone to cracks near the rear, upper shock mount bolt holes from both street/track use with higher cornering loads (and higher damper forces) as well as normal street use over extended time periods. Bolt these steel reinforcement plates on top of the rear shock tower sheet metal to strengthen this known weak area and prevent these cracks. Can be used with OEM style rubber RSMs or spherical RSMs. Can be bolted or welded in place. To install just place above the shock tower, underneath the RSM top nuts, as shown below - takes mere minutes to install.
SPRING RATES : While AST-USA provides you with the shocks only, Lang Racing Develoment offers the unique option for racers to pick their own front and rear spring rates at a reduced cost. These options will included new Hypercoil or Swift springs depending on the rates you request, AST rear ride height adjusters, and nylon rear spring alignment platforms. We know that every application is different so we let you tell us what rates you need, or just select "custom" and we can discuss with you your specific spring needs and find the best solution for you.
HELPER SPRINGS : We have found that certain applications benefit greatly from helper springs. When lowering the rear of an E46 the shock travel is usually longer than the short spring required in the stock location which can sometimes make the spring fall out when jacking up the car. A nightmare when the car needs to be serviced or even when changing a tire. To solve this we use a helper spring which keeps the spring in location when uncompressed but acts as a flat spacer when compressed, allowing the linear spring to do all the work. This can also be beneficial on a coil over shock that has a lot of travel like in rally applications.