DBA Brakes for the Subaru WRX STI: Which Parts Fit

By Core Brake Parts Tech Team — Circleville, OH warehouse

DBA makes rotors and pads for every Subaru WRX STI from 2004 through 2021, but which part fits depends on which Brembo system your car has. The 2004 to 2017 STI uses a four-piston front and two-piston rear Brembo setup, while the 2018 to 2021 STI moved to monoblock six-piston fronts with larger rotors. Match the part to your generation first, then pick the series (Street, 4000 or 5000) and pad compound for how you drive.

The Three STI Brake Generations You Need to Know

Every US-market STI came with Brembo calipers, but the parts that bolt to them changed twice. Getting the generation right is the single most important step when you order rotors or pads.

Subaru's own announcement of the 2018 STI describes the change as stronger monoblock six-piston front calipers, monoblock two-piston rears, larger drilled rotors all around, and new pads with significantly greater surface area. That last detail is why a pad or rotor listed for a 2017 STI is not a match for a 2018: the friction surface itself changed. The 2018 update also brought the STI's first 19-inch wheels, and the larger calipers need a big wheel to clear them.

The quickest way to confirm your generation is to look through the front wheel. A six-piston caliper is noticeably longer and wraps more of the rotor than the four-piston unit. If you have swapped calipers from a newer car, order parts for the calipers that are on the car, not the model year on the title.

DBA Rotor Series Explained: Street, 4000 and 5000

DBA sells several rotor families, and the names describe construction and intended use more than price.

Street Series

DBA positions Street Series rotors as OE-level replacements for daily drivers. They use the brand's Kangaroo Paw vane design, a baked-on zinc and aluminium EnShield coating for corrosion resistance, and are offered in a T2 slotted pattern with bi-symmetrical CNC-machined slots that give pad dust and gases an exit path. For a 2018 to 2021 STI that is driven on the street, the DBA Street Series T2 slotted front rotor for the six-piston Brembo STI is the straightforward choice.

4000 Series

The 4000 Series is a one-piece direct-replacement rotor cast from high-carbon alloyed iron and put through what DBA calls Thermal Stability Profiling, a heat-treatment cycle meant to improve stability and durability. It uses Kangaroo Paw ventilation, which DBA describes as 144 diamond and teardrop pillars giving up to 30 percent more surface area and 20 percent better cooling than a straight-vane rotor. Thermographic paint on the rotor changes colour at set temperatures so you can see how hot your brakes actually got after a hard session. Finishes include HD (plain), T3 slotted, and drilled versions; DBA itself notes that drilled patterns are not recommended for track days. For a 2008 to 2017 STI, the DBA 4000 Series HD plain rear rotor is a strong upgrade over a plain replacement disc.

5000 Series

The 5000 Series takes the same ring technology and bolts it to an anodised 6061-T6 aluminium hat with aerospace-standard bolts and crimp nuts. The two-piece design cuts unsprung weight and lets the iron ring expand evenly as it heats. The practical advantage for a track car is that the rings wear out and the hats do not: DBA sells replacement rings and hats separately. If you already run a 5000 Series front setup on a 2004 to 2017 car, the DBA 5000 Series front replacement rotor hat lets you rebuild the assembly without buying complete rotors. Because the 2004 car uses a different bolt pattern than the 2005 to 2017 cars, confirm the hat's bolt pattern against your hub before ordering.

Pad Choices: Street Compound or Race Compound

The pad matters as much as the rotor, and this is where most STI owners get it wrong. DBA's RP (Race Performance) pads are a carbon-fibre-reinforced race compound built for circuit use, where DBA says brake temperatures run above 350 degrees C (662 degrees F). DBA states plainly that the RP range is not suitable for road use: a race pad needs heat to work, and on a cold street stop it can feel grabby, noisy, or weak, and it will wear rotors faster.

• Track and time-attack cars: the DBA RP front race pad set DB1845RP (2015-2021) and the DBA RP rear race pads DB15007RP (2018-2021). DBA recommends pairing RP pads with its 5000 Series T3 slotted rotors.
• Dual-duty cars driven to the track: most owners run a street or performance-street pad day to day and swap to race pads at the circuit. Swapping pads between compounds without re-bedding, or without cleaning the rotor, is a common cause of vibration.
• Daily drivers: stay with a street compound. Browse brake pads by vehicle or the ceramic brake pad range for a quiet, low-dust option.

Note the year split on the pads above: the front RP set covers 2015 to 2021, but the rear set is listed for 2018 to 2021 only, because the 2018 rear monoblock caliper takes a different pad.

Other STI Parts in Our Catalog

DBA is not the only brand that makes STI-specific parts. For the 2018 and newer car, we also carry the EBC Bluestuff NDX rear pad set, the Hawk HP Plus rear pads, the Hawk DTC-30 rear race pads, and GiroDisc two-piece slotted rotors for the front and rear. Read the rear GiroDisc listing carefully: it requires trimmed rear pads, which is exactly the kind of fitment detail that decides whether a job goes smoothly.

What to Replace at the Same Time and How Hard the Job Is

Replace rotors and pads as a set per axle, and always bed new pads to new rotors following the pad maker's procedure. On a Brembo fixed caliper, pads come out once the retaining pins and anti-rattle spring are removed; the caliper stays on the car for a pad-only job. Rotor replacement means unbolting the caliper from the knuckle, so support it rather than letting it hang on the hose.

• Brake fluid: any car that sees track time should have fresh, high-boiling-point fluid. Use the fluid type specified in your owner's manual or on the reservoir cap.
• Hardware: inspect pad pins and springs and replace them if corroded. See brake hardware kits.
• Lines: braided brake lines firm up the pedal on an older car whose rubber hoses have aged.
• Torque: tighten caliper mounting bolts and wheel nuts to the values in the factory service manual; do not guess.

For someone with a jack, stands and a torque wrench, a pad swap is a manageable driveway job, and rotors add a little more work. The difficulty is not the wrenching; it is ordering the right generation of part the first time.

Frequently Asked Questions

Will 2017 STI rotors fit a 2018 STI?

No. The 2018 STI moved to six-piston front and monoblock two-piston rear Brembo calipers with larger rotors and bigger pads, so 2004 to 2017 rotors and pads are a different part. Order parts listed for 2018 to 2021.

Can I use DBA RP race pads on the street?

DBA says the Race Performance range is not suitable for road use. The compound is designed for track temperatures above 350 degrees C, so it does not work well cold. Use a street compound for daily driving.

Is the DBA 5000 Series worth it over the 4000 Series?

For a track car, often yes: the aluminium hat reduces unsprung weight and the iron ring can be replaced on its own when it wears. For a street car, a 4000 Series or Street Series one-piece rotor gives most of the benefit for less money.

What is the difference between T2 and T3 slots?

T2 is DBA's bi-symmetrical slot pattern used on the Street Series. T3 is a tri-symmetrical pattern with more slots and more exit points for pad dust and gas, aimed at harder performance driving.

Does a 2004 STI take the same parts as a 2005 STI?

Not always. The 2004 STI uses a 5x100 wheel bolt pattern and the 2005 and later cars use 5x114.3, which changes the rotor hat. Check the bolt pattern listed for any rotor or hat before ordering.

Should I drill or slot my STI rotors for track use?

Slotted or plain. DBA itself does not recommend its drilled rotor patterns for track day use; slotted T3 rotors are its pick for circuit driving.

Sources

1. Subaru U.S. Media Center: 2018 WRX and WRX STI - 2018 STI six-piston monoblock front and two-piston monoblock rear Brembo, larger drilled rotors, larger pads, 19-inch wheels
2. FastWRX: STI Brembo Brakes - 2004 STI four-piston front on 5x100; 2005 and later on 5x114.3
3. DBA: 4000 Series rotors - one-piece high-carbon iron, Thermal Stability Profiling, Kangaroo Paw 144 pillars, thermographic paint, drilled not for track
4. DBA: 5000 Series rotors - two-piece with 6061-T6 anodised aluminium hat, NAS bolts, replacement rings and hats
5. DBA: Street Series rotors - T2 bi-symmetrical slots, EnShield coating, daily-driver positioning
6. DBA: Race Performance brake pads - carbon-fibre race compound, above 350 degrees C, not for road use, pair with 5000 Series T3