BC Racing ER Series — Independent Compression and Rebound Control
The BC Racing ER Series is built for the driver who wants to fine-tune a setup rather than settle for a single combined adjustment. It pairs large external reservoirs, front and rear, with a twin-piston design that separates rebound and compression tuning into two independent 30-way dials. The reservoirs carry more oil than a conventional coilover and house the secondary piston that controls compression, so the damper resists heat and holds its behavior lap after lap. For anyone chasing the last few percent of control on the street or at the track, the ER Series gives you the range to dial it in.
Why External Reservoirs Matter
Coilovers generate heat as they work, and heat thins the damper oil, which is what causes fade under sustained hard use. The ER Series moves more oil into large external reservoirs so the unit runs cooler and stays consistent far longer than a conventional single-tube design. Those same reservoirs house the secondary piston that makes independent compression adjustment possible, so the extra capacity does double duty. The result is a coilover that keeps performing when the pace picks up and the miles add up.
Separate 30-Way Compression and Rebound Tuning
Most coilovers combine compression and rebound into one adjustment, which means every change is a compromise. The ER Series splits them, giving you a dedicated 30-way rebound dial and a dedicated 30-way compression dial. You can firm up body control without punishing ride quality, or soften compression over rough surfaces while keeping rebound tight, tailoring the car to your driving and your roads. It is the natural choice when a single combined adjustment no longer gives you enough control.
Fitment, Support, and the Springrates Guarantee
The ER Series is available across a wide range of chassis, and each kit is built specifically for its application, so enter your vehicle on the listing to confirm the correct fitment. Every BC Racing coilover is a fully rebuildable monotube design backed by a two-year warranty handled through BC Racing North America, and custom spring rates are available at no extra cost with Swift Spring upgrades offered on request.
At Springrates, we've been an authorized BC Racing retailer since 2005. If you're deciding between series, our coilover comparison guide breaks down every option, and our team is here to help. We'll give you a straight answer.