BC Racing has become one of the most popular performance coilover brands in the world — and with good reason. Their kits offer 30-way damping adjustment, independent ride height adjustment, monotube damper construction, and fitments for nearly every modified platform on the road. They've earned a reputation as the value-leader of the premium coilover market.
But BC Racing makes seven distinct coilover series — BR, DS, ER, HM, RM, ZR, and ZX. The naming isn't intuitive, and the differences aren't always obvious. As one of the largest BC Racing authorized retailers in North America, the question we hear most often is simple: which series is right for my build?
This guide breaks down every BC Racing series, what makes each one unique, and who should buy which. By the end, you'll know exactly which kit fits your goals.
BC Racing Coilover Series at a Glance
- BR Series — The best-selling all-rounder. Daily driving, stance, and weekend canyon runs.
- DS Series — Digressive valving for sharper response and stiffer street feel.
- ER Series — External reservoir dampers for serious track use.
- HM Series — Higher-spec internals built for aggressive performance driving.
- RM Series — Inverted monotube design for premium feel and durability.
- ZR Series — Track-spec coilovers for dedicated motorsport applications.
- ZX Series — Specialized fitments for select chassis with unique requirements.
BC Racing BR Series — The Best-Seller
The BR Series is the coilover that built BC Racing's reputation. It's also the one we sell more of than every other BC series combined.
The BR is engineered as a true do-it-all kit. Daily drivers get a noticeably better ride than most "budget" coilovers, stance enthusiasts get massive height adjustment range, and weekend canyon drivers get enough adjustability to dial in a sharper setup when they want it. It features a 30-click damping adjustment, independent ride height and preload adjustment, monotube damper construction, and vehicle-specific spring rates engineered by BC Racing for each application.
Best for: Daily-driven street cars, stance builds, show cars, weekend spirited drivers, and anyone wanting the most proven all-rounder in the BC lineup.
Not for: Dedicated track cars that need external reservoir cooling or extreme spring rates.
BC Racing DS Series — Sharper Response
The DS Series shares the BR's architecture but swaps in digressive piston valving. In plain terms: digressive dampers resist low-speed shock movement (body roll, dive, squat) while staying compliant over high-speed inputs (bumps, expansion joints).
The result is a coilover that feels tighter and more responsive in cornering without becoming punishing on rough pavement. Steering response improves, mid-corner stability improves, and the car feels more connected at the limit. Compared to the BR, the DS feels stiffer in transitions but doesn't necessarily ride worse on the street.
Best for: Performance-focused street drivers, autocross competitors, owners who track their car occasionally, and anyone who wants a sharper-feeling setup than the BR delivers.
Not for: Buyers prioritizing maximum comfort or those who don't drive hard enough to feel the difference.
BC Racing ER Series — External Reservoir Performance
The ER Series steps into serious performance territory. ER stands for external reservoir — these dampers feature a remote oil reservoir connected to the strut body via a high-pressure line.
Why does it matter? External reservoirs increase oil capacity and improve heat dissipation, which keeps damping consistent during sustained hard driving. On a regular twin-tube or non-reservoir monotube, repeated hard inputs heat the damper oil and cause fade — the suspension progressively gets softer and less controlled. External reservoirs eliminate this. ER dampers also typically use independently adjustable rebound and compression damping for finer tuning control.
Best for: Track day enthusiasts, time attack drivers, road racers, and anyone whose driving consistently overworks a standard damper.
Not for: Daily drivers who never see a track — the extra capability is overkill and the reservoir mounting can be inconvenient on a street car.
BC Racing HM Series — Higher Spec Internals
The HM Series sits between the BR/DS street coilovers and the ER/ZR track coilovers. HM kits use higher-specification internals — better seals, upgraded valving, and tighter manufacturing tolerances — without going to an external reservoir.
Think of the HM as a premium street-and-light-track coilover. It offers better long-term durability than the BR, sharper performance than the DS, but doesn't require the reservoir setup of the ER. It's the right choice when you want a meaningful upgrade from the BR but don't need a dedicated motorsport kit.
Best for: Enthusiasts who want a clear step up from the BR but don't need external reservoirs, drivers who do occasional HPDE or autocross events, and owners building a high-end street car.
BC Racing RM Series — Inverted Monotube
The RM Series features an inverted monotube design. In an inverted damper, the shock body sits at the top and the piston rod points downward — the opposite of a conventional damper.
The benefit: inverted dampers place the heavier components closer to the chassis and the lighter components closer to the wheel, reducing unsprung weight. This improves wheel control over bumps and gives a more refined feel. Inverted designs are also typically more rigid, which improves precision under hard cornering loads. This is the construction style you'll find on factory dampers from manufacturers like Porsche and BMW M.
Best for: Premium street builds, drivers who want OE-quality damper feel, and owners chasing the best ride quality and feel BC offers in a non-reservoir kit.
BC Racing ZR Series — Track-Spec Motorsport
The ZR Series is BC Racing's dedicated track and motorsport coilover. ZR kits feature aggressive spring rates, high-end valving, and construction spec'd specifically for the demands of road racing, time attack, and competitive motorsport.
Best for: Dedicated track cars and motorsport applications where street comfort is not a consideration.
Not for: Street use. The ride quality and spring rates are tuned for grip, not comfort.
BC Racing ZX Series — Specialized Fitments
The ZX Series covers specialized applications and select chassis with unique suspension requirements that fall outside the standard BR/DS/ER/HM lineup. ZX kits are typically engineered for specific vehicles where standard fitments wouldn't deliver the right characteristics.
Best for: Owners of supported chassis where the ZX is the recommended fitment. Check your specific vehicle for availability.
How to Choose: A Quick Decision Framework
Cut through the series naming and answer four questions:
- Will the car see the track? If yes, frequently — look at ER or ZR. If occasionally — HM or DS. If never — BR or RM.
- Is comfort or sharpness the priority? Comfort first — BR or RM. Sharpness first — DS or HM.
- What's your budget? The BR is the most affordable, with each step up adding capability and cost.
- How important is feel and refinement? If you want premium damper feel on the street, the RM's inverted design is the standout.
For 80% of buyers, the answer is the BR Series. That's not a sales pitch — it's the reason the BR exists. It does almost everything well, fits nearly every modified chassis, and the price-to-performance ratio is unmatched in the segment.
Swift Springs Upgrades
Every BC Racing coilover can be upgraded with Swift Springs — premium Japanese coilover springs made from a proprietary steel alloy. Swift springs are lighter, more responsive, and hold their rate more consistently than the standard springs that come on BC kits. Whether you're upgrading a BR for the street or building an ER setup for the track, swapping to Swift is the single most impactful upgrade you can make to any BC coilover.
Why Buy BC Racing Coilovers From SPRINGRATES®
SPRINGRATES® is one of the largest BC Racing authorized retailers in North America. We've sold thousands of BC kits across every series in the lineup, and our team can help you choose the right series, spring rates, and configuration for your specific vehicle and driving goals. We verify fitment on every order, offer custom spring rate options on most kits, and back every purchase with our Low-Price Guarantee.
Free shipping on orders over $250. 0% APR financing available. Shop the full BC Racing lineup or contact us to talk through your build with a suspension specialist.
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