BC Racing Series Explained: BR, DS, ER, RM, HM, ZR, ZX and ASP
Which BC Racing series do you need? For most street cars and weekend track days, the BR Series coilover kit is the right start. Move to another series only when your car or your driving asks for it.
Spend ten minutes on forums and you will see eight names thrown around: BR, DS, ER, RM, HM, ZR, ZX and ASP. They are not eight versions of the same kit. Each one answers a different question about corrosion, heat, chassis layout, damping control or keeping the factory dampers. Here is how we walk customers through the choice at the counter.
What Every BC Racing Series Shares
Start with what does not change. Every BC Racing kit uses nitrogen-charged monotube dampers. BC Racing builds its kits in Taiwan. The catalog covers hundreds of fitments, and BC splits kits by body style and drivetrain when the chassis changes underneath.
Ride height is full-length on BC Racing kits. You set height at the lower mount, and the spring perch sets preload, so one adjustment does not fight the other. A locking collar holds each setting. BC Racing describes its lower locking ring as a patented concave design. Camber-adjustable upper mounts come on most applications.
Warranty terms come from BC Racing North America. BC Racing North America lists a two-year limited warranty on full kit orders, from the date of purchase, subject to its warranty terms. Coverage applies to the original purchaser only.
So the series choice is not about quality tiers. It is about which features your build needs. Our guide to BC Racing coilovers covers why the brand is so popular. This guide is the chooser.
BR and DS: Single-Knob Damping
BR Series
The BR Series is the volume seller across the catalog. It gives you 30-click simultaneous compression and rebound on a single knob. One knob means one decision: firmer or softer. For a street car that sees a few track days a year, that is all the damping control most drivers ever use.
If you are lowering a street car, the BR Series is where we start the conversation. You get height, damping and camber adjustment on most applications at a value-performance price point.
DS Series
The DS Series keeps the same 30-click simultaneous compression and rebound and the same single knob. The change is the shock body. DS uses stainless-steel shock bodies for corrosion resistance. If your car sees salted winter roads or lives near the coast, that is the reason to look at DS. The damping control itself is the same as BR. BC's series pages note that noise from DS kits is not covered by warranty.
ER, RM and HM: Heat and Chassis Layout
ER Series
The ER Series adds an external reservoir. Damping is still 30-click simultaneous compression and rebound. The reservoir holds extra oil and helps the damper shed heat under sustained track use. Hot oil thins out, and that is where damper fade starts. If your sessions run long and hard, ER is built for that problem.
RM Series
The RM Series uses an inverted monotube damper, front and rear, for cars with MacPherson strut suspension. It keeps 30-click simultaneous compression and rebound. Inverted struts are chosen for bending stiffness. The thicker tube sits where the strut takes its cornering load, which keeps it smooth and stiff when you lean on it.
One myth to clear up. An inverted strut is not a weight-loss part. Unsprung weight is the mass the springs do not carry: wheel, tire, hub, brakes, knuckle and part of the arms and damper. Lighter wheels and brakes cut it. Flipping the strut does not, on its own.
The Mustang is a good example. We list the RM Series for the 2005 to 2014 Mustang RWD and for the 2015 to 2021 S550. The S550 has separate listings for cars without MagneRide and with MagneRide. BC Racing also builds the RM Series for the 2024 and newer S650, with and without MagneRide, so call us to order one.
HM Series
The HM Series is for track builds on cars without MacPherson struts, such as double wishbone or multi-link layouts. It uses an inverted monotube where the application allows. You may see the older name HR in forum posts. BC Racing renamed HR to HM, and HM is the current name. Swift Springs ship standard on HM kits on most fitments.
ZR and ZX: The Three-Way Adjustable BC Racing Series
Up to this point, every series moves compression and rebound together. ZR and ZX split them apart. You get separate knobs for rebound, low-speed compression and high-speed compression. Low-speed compression handles body motion, like roll and pitch. High-speed compression handles sharp hits, like curbs and expansion joints.
ZR Series
30-click rebound, 15-click low-speed compression, 12-click high-speed compression. Three-way independently adjustable. Swift Springs ship standard on most fitments.
ZX Series
30-click rebound, 20-click low-speed compression, 12-click high-speed compression. Monotube, with track-oriented digressive damping. Rebuildable, with custom spring rates available. ZX has the most adjustment in the BC Racing lineup.
Three-way adjustment is only worth it if you will test and log changes. On a street car it mostly adds knobs. On a purpose-built track car with a driver who reads tire temps, it is the tool you want. ZX is a series option on some listings, such as the 2005 to 2014 Mustang. Check the Series options on your car's product page. Our guide to adjustable coilovers explains what each kind of adjuster does.
ASP and Cars With Factory Electronic Damping
ASP is a parallel option, not a step on the ladder. BC Racing describes it as an adjustable spring perch kit with car-specific springs. It is for owners who want their factory electronic dampers to keep working. It keeps the OEM dampers and adds ride height adjustment. We do not list ASP on our site, so call us to check your car.
BC Racing also lists full coilover kits for some cars with factory electronic damping, and the title names it. Examples are the 2015 to 2021 Mustang RWD "With Magneride" and the 2007 to 2013 M3 "Originally with EDC" (E92 and E90). Others are F80 M3 and F82 M4 kits marked "EDC", Giulia kits marked "W/ DDC" and MINI Cooper kits marked "With DDC". Where a title says "Excl. Magneride" or "W/O EDC", that kit is not for a car with those dampers. Ordering for the wrong damping system is an easy mistake, and a costly one to undo.
Swift Springs, Custom Rates and Custom Builds
Every BC Racing kit ships with a spring rate chosen for your car. If you want something different, BC Racing builds kits with custom spring rates. Swift Springs SPEC-R springs are the upgrade spring option on most BC Racing fitments. They ship standard on HM and ZR kits on most fitments.
Some listings limit Swift. Our listing for the 2015 to 2021 Mustang GT without MagneRide says Swift Front Only in the title, for example. Swift says it was founded in Tokyo in 1997 as the motorsport spring brand of Tokyo Hatsujo. Our guide to BC Racing and Swift Springs goes deeper on that pairing.
Swift springs, custom spring rates and Extreme Low builds are ordered through the custom build option for BC coilovers. BC Racing North America introduced a custom build fee effective June 30, 2025. We pass it on without markup. We also list Swift springs for BC coilovers on their own, as a full set of four.
How to Choose Your BC Racing Series
Street car, occasional track day. BR Series. Add Swift springs if you want them.
Street car in a salt-belt state. DS Series for the stainless-steel shock bodies.
Long, hot track sessions. ER Series for the external reservoir.
Track build on a MacPherson strut car. RM Series.
Track build without MacPherson struts. HM Series.
Dedicated track car, driver who tests. ZR Series, or ZX where your product page lists it as an option.
Factory electronic damping. Use the listing that names your car's damping system, or call us.
Not every series is built for every car. The product page for your car shows what we list for it. Confirm fitment on the product page, or call 1-800-460-9106 with your VIN and we will check it for you.
BC Racing is one part of the performance suspension brands we carry. KW brings German engineering, with KW V3 for independent compression and rebound on a twin-tube design. Fortune Auto hand-builds custom-valved kits in Virginia. TEIN brings deep Japanese-platform coverage, and Öhlins brings its racing pedigree with DFV on Road & Track kits. If BC Racing is not the fit, one of those may be.
Frequently Asked Questions
What is the difference between BC Racing BR and DS?
Both have 30-click simultaneous compression and rebound on a single knob. The DS Series uses stainless-steel shock bodies for corrosion resistance. Pick DS if your car sees road salt or coastal air. Pick BR if it does not.
Is the BC Racing BR Series good for track days?
Yes, for street cars that see occasional track days. It is the volume kit for that use. If your sessions run long and the dampers start to fade, the ER Series adds an external reservoir for heat. Dedicated track cars often move to RM, HM, ZR or ZX.
What is the difference between BC Racing ZR and ZX?
Both are three-way adjustable. ZR has 30-click rebound, 15-click low-speed compression and 12-click high-speed compression. ZX has 30-click rebound, 20-click low-speed compression and 12-click high-speed compression. ZX is a series option on some listings, so check the Series options on your car's product page.
Is BC Racing HR the same as HM?
Yes. BC Racing renamed the HR Series to HM some years ago. HM is the current name. It is built for track use on cars without MacPherson strut suspension, and Swift Springs ship standard on most HM fitments.
Do BC Racing coilovers come with Swift springs?
Swift Springs ship standard on HM and ZR kits on most fitments. On other series, Swift is an upgrade through a custom build. A few listings say Swift Front Only or Swift Rear Only in the title, so check your car's listing.
Which BC Racing series works with MagneRide or EDC?
Some BC Racing listings are built for cars with factory electronic damping. Examples are the 2015 to 2021 Mustang with MagneRide and the E90/E92 M3 originally with EDC. Others are for cars without it. BC Racing also makes ASP for selected cars. Call 1-800-460-9106 with your VIN so we can match the right listing.
Does the BC Racing warranty change by series?
BC Racing North America lists a two-year limited warranty on full kit orders, from the date of purchase, subject to its warranty terms. BC's series pages note that noise from the DS, RM, ER, HM, ZR and ZX kits is not covered by warranty.
Not Sure Which Series Fits?
Tell us what you drive, how you drive it and where you live. That narrows the choice to one or two kits fast.
Call 1-800-460-9106 with your VIN and we will confirm fitment, series and any Swift or custom spring options for your car. Free shipping across Canada on most kits.
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