BC Racing Coilovers: Custom Fits and Swift Spring Upgrades
Every car has its own suspension geometry. That is why a BC Racing coilover kit is built for the exact cars it goes on. Damper lengths, spring rates, top mounts and bearings are all chosen for that chassis, so the kit replaces the factory suspension directly. There are no universal parts and no guesswork.
Most customers never need to go past the standard build. For the ones who do, BC Racing Swift spring upgrades, custom spring rates and extreme-low setups are on the menu. Below we explain how that works, what the Swift option actually gets you, and how the BC Racing custom build fee fits in.
How BC Racing Coilovers Fit Out of the Box
BC Racing puts real work into fitment. Its catalog covers more than 800 fitments, and it splits body styles and drivetrains into separate kits when the chassis changes. Each coilover kit ships assembled to its fitment spec and ready to install. That baseline gives you three things right out of the box.
Correct ride height and damper travel. The damper is specified for your chassis, so the car can sit at a usable drop without running out of shock stroke. Ride height is set at the lower mount, and the spring perch sets preload.
Car-specific top hats and bearings. The upper mounts are built for the exact car, not a universal part. Camber-adjustable upper mounts come on most applications.
Confidence in fit and function. Bolt-on installation on most applications, with no cutting, welding or trimming.
This is the baseline on BC Racing BR Series coilovers, the series that sells the most in the BC Racing catalog. It comes with 30-click simultaneous compression and rebound. It is also where most owners should start before deciding whether they need anything custom. Our BC Racing coilovers overview covers the full series ladder.
When the Standard Setup Is Not Enough
Enthusiasts and racers sometimes want more than the standard build. BC Racing has done customization for years. Most requests fall into three groups.
Custom spring rates. 8 kg, 10 kg, 12 kg or higher. Matching the spring rate to the car's weight, tires and use is how a good setup becomes a fast one.
Swift spring upgrades. Swift Springs SPEC-R springs are an upgrade option on most BC Racing fitments. They ship standard on HM and ZR Series kits on most fitments.
Extreme-low setups. BC Extreme Low coilovers are set up for aggressive ride height targets. Ask us what that does to bump travel on your car before you order.
Custom work is a small share of BC Racing orders. Most owners are well served by the standard kit. When custom work is needed, it takes skilled hands and extra time.
BC Racing Swift Spring Upgrades: What You Get
Who Makes Swift Springs
Swift says it was founded in Tokyo in 1997 as the motorsport spring brand of Tokyo Hatsujo (Tohatsu), a spring maker dating to 1924. Its springs use an alloy Swift calls HS5.TW, along with its own winding process. SPEC-R is the Swift product name you will see on BC Racing upgrades. Swift is a spring brand, not a coilover brand. BC Racing is the main coilover brand where Swift springs come up.
How Swift Springs Help on Track
A lighter spring trims unsprung weight. Unsprung weight is the mass the springs do not carry. Part of a coilover spring's own mass moves with the wheel, so a lighter spring helps a little. Swift markets its springs as light for their rate.
More usable stroke before coil bind. Coil bind is geometric. It happens when the coils touch. Swift says its spring design gives more working travel before that point, which helps on rough roads and big compressions. Our guide to spring physics explains coil bind and sag.
Resistance to sag. When a spring sags, it loses free length and the car sits lower. The rate itself barely changes. Swift says it designs its springs for durability against loss of spring height. That means your ride height stays where you set it.
Swift springs are an option on BC Racing kits and on Fortune Auto custom builds. Yes, the upgrade costs more than standard springs. For a serious build, many owners find it worth it.
Who Swift Makes Sense For
Track, time attack, autocross and dedicated drift builds where spring behavior over time matters. See our guide to drift coilovers for that use. For a mild street drop on a daily driver, standard BC Racing springs do the job, and most customers do not need the extra spend.
The BC Racing Custom Build Fee
BC Racing North America introduced a custom build fee, effective June 30, 2025, on coilover kits that need customization before they ship. That covers work like Swift spring swaps, custom spring rates and Extreme Low builds.
The reason is simple. Custom work takes technician time that a standard kit does not. A separate fee keeps that cost on the custom order instead of folding it into every base kit.
What the Fee Actually Covers
A custom build is more than pulling a different box off the shelf. Here is what happens when you order a customized BC Racing coilover kit.
Disassembly. The coilover comes out of inventory and goes to the assembly bench.
Spring swap or rate change. Standard springs come off and Swift units or a different rate go on.
Setup changes. Ride height setup and Extreme Low parts as requested.
Reassembly. The kit is put back together to spec, packed and prepared to ship.
That is skilled technician time and parts tracking. It is not free labor.
How Coilovers.com Handles the Custom Build Fee
We pass the fee on without any markup. You pay the fee for the custom build work BC Racing performs on your coilover kit. We handle the order, help you pick options, check the specs and follow up while the kit is being built.
You pay the fee, and we do the rest. There are no hidden charges.
Check the Fee Before You Order
Fees and pricing can change. Before you finalize a custom BC Racing build, call us at 1-800-460-9106. We will confirm the current fee, current Swift pricing and the current lead time on your configuration.
Why a Separate Custom Build Fee Is Fair to Buyers
A separate fee does three things for the customer.
It keeps customization intentional. Buyers think twice before adding options they do not need for their use.
It keeps standard kits standard. Custom labor is tracked on the custom order, not mixed into the price of every BR Series kit.
It puts the cost where the work is. The customers who need custom work cover the cost of that work. The customers who do not are not paying for someone else's build.
The fee is honest about how custom suspension work has always gone. A skilled tech works on your coilover kit before it ships.
Where BC Racing Fits in the Brands We Carry
We are an authorized dealer for every brand we carry, and each one suits a different buyer. BC Racing's series range covers a lot of adjustment at a fair price. Custom rates and the Swift Springs upgrade are available across most fitments. After you buy, replacement parts can usually ship on their own, so you do not need to send the full kit out and wait.
BC Racing describes its lower locking ring as a patented concave design. Keep that locking collar and the threads clean, and the adjustment stays easy for years. BC Racing North America currently lists a two-year limited warranty on full kit orders, subject to its warranty terms.
KW is a German brand with TÜV certification on most kits. Fortune Auto builds every kit by hand with custom valving. Öhlins brings TTX twin-tube technology and decades of racing history. TEIN, Feal and Bilstein each have their own strengths. Tell us how you drive, and we will help you find the right kit.
Frequently Asked Questions
Are BC Racing coilovers car-specific?
Yes. Every BC Racing coilover kit is built for specific cars, and some kits cover more than one model. Damper lengths, spring rates and mounting hardware are matched to that chassis. You do not pick generic parts. You order the kit built for your car.
What are Swift springs and why do they cost more?
Swift says it was founded in Tokyo in 1997 as the motorsport spring brand of Tokyo Hatsujo (Tohatsu). Its springs use an alloy it calls HS5.TW. SPEC-R is the product name on BC Racing upgrades. Swift says it designs its springs for durability against loss of spring height. The price reflects that material and process.
Do I need Swift springs on a daily driver?
Usually not. Standard BC Racing springs work well for street use and give most daily drivers the handling and ride height range they need. BC coilovers with Swift springs make the most sense on track, time attack, autocross and serious drift builds.
What does the BC Racing custom build fee cover?
It covers the technician work in a custom build. That means disassembly, spring swaps or rate changes, Extreme Low setup, and reassembly to spec. Parts such as Swift springs are priced on their own. Call us for the current numbers.
Does Coilovers.com mark up the custom build fee?
No. You pay the fee BC Racing charges for the custom build work. We handle the rest of the order. Call 1-800-460-9106 before you order, and we will confirm the current fee and the lead time on your configuration.
How long does a custom BC Racing build take to ship?
It varies. Custom work adds build time on top of the standard kit. Uncommon spring rates or extreme-low setups can take longer. We confirm the current lead time when we place the order and keep you updated through production.
What coilovers fit my car?
Start with your exact year, make and model. Every BC Racing kit is built for specific cars, and the catalog splits body styles and drivetrains into separate kits. Search our site for your car. If your chassis is not listed, call 1-800-460-9106.
Can I buy Swift springs on their own?
Yes. We stock Swift springs for BC coilovers as a full set of four or a half kit of two. Standard BC Racing springs are also sold individually. Match the spring rate, length and inner diameter to your kit before you order.
Can I order custom coilovers with my own spring rates?
Yes, through a BC Racing custom build. You can request custom spring rates, Swift springs or an Extreme Low setup. The custom build fee covers the technician time, and we pass it on without markup.
Is a BC Racing Swift spring upgrade reversible?
Yes. Springs are removable parts of a BC Racing coilover kit. You can start with standard springs and move to Swift later, or the other way around. Reset ride height and preload after the swap, tighten every locking collar, then get an alignment.
Keep reading: Our guides to spring rates and BC Racing series.
Talk to Us About a BC Racing Kit
If you are still unsure, talk to someone who can help you choose the right kit for your car and how you drive it.
We carry BC Racing, KW, Fortune Auto, Öhlins, Feal and TEIN. We know these brands and the cars they fit. Call 1-800-460-9106 and tell us what you drive and what you are trying to do. We will point you to the right kit and give you a straight answer, with no upsell.
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