Repeatable Lap-After-Lap Braking
Built for circuit, time-attack, drift, and rally use where pedal consistency matters from out-lap to checker.
Pay in installments of $221.25 with
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Shipping Estimate
USA
- USA
- CAN
- USA
- CAN
Ships within 48 hours · Estimated delivery Aug 14 - Aug 19
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For Your Every Summer RSVP, with Code: SUMMER15
Description
Circuit Racing TR48 Front Wheel 4-Piston Big Brake KitRacing Series Circuit Front Axle 4 Piston TR48 Front 4 Piston Big Brake Kit A front axle 4 piston monoblock BBK engineered for circuit, time attack, drift, and rally use. Forged caliper, two piece directional rotors, and a wide pad window deliver thermal repeatability and a consistent pedal from out lap to checker. Monoblock forged aluminum 4 piston, 38 41 mm 355 or 380 mm 32 mm Two piece rotors Pads to 750 C, Option B SS braided lines Why Builders
Racing Series · Circuit · Front Axle · 4-Piston
TR48 Front 4-Piston Big Brake Kit
A front-axle 4-piston monoblock BBK engineered for circuit, time-attack, drift, and rally use. Forged caliper, two-piece directional rotors, and a wide pad window deliver thermal repeatability and a consistent pedal from out-lap to checker.
Monoblock forged aluminum
4-piston, 38 / 41 mm
Ø355 or Ø380 mm × 32 mm
Two-piece rotors
Pads to 750 °C, Option B
SS braided lines
Why Builders Choose the TR48
The TR48 caliper body is forged from a single aluminum billet for stiffness under sustained line pressure. Four pistons, 38 mm × 2 and 41 mm × 2, generate 49.36 cm² of total clamp area per caliper, with a staggered bore layout that promotes even pad pressure distribution and a more linear bite as pad temperature climbs. Racing-spec pistons run without dust boots to clear hot brake gases on track.
Monoblock Forged Caliper
Forged from a single aluminum billet for stiffness under sustained line pressure.
49.36 cm² Piston Area
38 mm × 2 and 41 mm × 2 pistons generate 49.36 cm² total piston area per caliper.
Two-Piece Directional Rotors
Ø355 or Ø380 mm × 32 mm two-piece rotors with internal ventilation and left/right specific directional vanes.
Wide Pad Window
Standard 0–600 °C pads for sprint and HPDE, or Option B 0–750 °C pads for endurance heat loads and aggressive circuit work.
Race-Service Hardware
Stainless braided lines, vehicle-specific brackets, rotor hats, and required bedding instructions support a real track workflow.
Technical Specifications & Kit Options
| Brake Caliper | ||
|---|---|---|
| Series | Racing Series — Circuit | |
| Model / Application | TR48 | |
| Axle Position | Front | |
| Piston Count | 4-piston | |
| Piston Type | Racing pistons without dust boots | |
| Piston Diameter | 38 mm × 2 / 41 mm × 2 | |
| Caliper Dimensions | 258.8 mm × 157.7 mm × 75.2 mm | |
| Total Piston Area | 49.36 cm² per caliper | |
| Manufacturing Process | Monoblock forged aluminum body | |
| Net Weight | 2.36 kg per caliper, without pads | |
| Surface Finish | Nickel-plated | |
| Recommended Wheel Size | 18 in or larger | |
| Recommended Rotor Size | Ø355–380 mm × 32 mm | |
| Brake Rotor Options | ||
| Rotor Option | Standard | Option B Racing |
| Rotor Material | Heat-treated high-carbon cast iron | Racing-grade heat-treated high-carbon cast iron |
| Axle Position | Front | Front |
| Rotor Dimensions | Ø355 / 380 mm × 32 mm | Ø355 / 380 mm × 32 mm |
| Construction | Two-piece rotor assembly | Two-piece rotor assembly |
| Ventilation | Internally vented | Internally vented |
| Rotor Hats | Application-specific alloy rotor hats | Application-specific alloy rotor hats |
| Rotor Mounting | Fixed or floating, depending on rotor size and vehicle application | Fixed or floating, depending on rotor size and vehicle application |
| Directional Design | Yes — left/right specific | Yes — left/right specific |
| Rotor Face Pattern | Curved slot / Grain slot / Wave slot / Drilled and slotted | Wave slot |
| Recommended Use | Sprint sessions, HPDE, dual-purpose street / track cars driven to events | Sustained high-temperature work, time attack, endurance racing |
| Brake Pad Options | ||
| Pad Option | Standard | Option B Racing |
| Compatible Rotor Material | Iron / steel rotors only | Iron / steel rotors only |
| Operating Temperature | 0–600 °C | 0–750 °C |
| Average Friction Coefficient | μ ≈ 0.38 | μ ≈ 0.45 |
| Recommended Use | Strong sprint and HPDE compound | Built for endurance heat loads and aggressive circuit work |
| Lines, Brackets & Service | ||
| Brake Line Construction | Three-layer reinforced | |
| Brake Line Material | PTFE inner liner / SUS304 braid / PVC outer sheath | |
| Caliper Mounting | Radial mount with vehicle-specific caliper brackets | |
| Caliper Brackets | Vehicle-specific caliper brackets | |
| Brake Line Fittings | Vehicle-specific, caliper-side and chassis-side vary | |
| Wheel Clearance | Minimum 18 in wheels; final clearance depends on wheel barrel, spoke geometry, rotor size, and bracket package | |
| Bedding-In Procedure | Required | |
Friction values vary with temperature, line pressure, and rotor condition. Choose the compound that matches your session length and chassis weight. Pads on this platform are designed for iron / steel rotor faces only. Do not use carbon-ceramic-only compounds.
Package List
Calipers ×2
2 × TR48 front monoblock forged 4-piston calipers with nickel-plated finish.
Brake Pads
Brake pads for both front calipers, selected from standard 0–600 °C or Option B 0–750 °C pad window.
Brake Rotors ×2
2 × two-piece internally vented front rotors, Ø355 or Ø380 mm × 32 mm, left/right specific.
Caliper Brackets ×2
Vehicle-specific radial caliper brackets for correct front caliper alignment.
Rotor Hats ×2
Application-specific alloy rotor hats matched to front hub location and rotor offset.
Brake Hoses ×2
Stainless braided front brake lines with PTFE inner liner, SUS304 braid, and PVC outer sheath.
The Bespoke Engineering Process
Every TR48 front circuit racing system is engineered around the vehicle’s front knuckle, hub location, rotor hat offset, wheel barrel, spoke clearance, brake line routing, front brake bias target, and intended motorsport use. The goal is not a generic universal fit; the goal is a front brake package that works with your chassis geometry and gives the driver repeatable pedal behavior from out-lap to checker.
1. Technical Consultation
We review the chassis, front suspension and knuckle setup, motorsport use, target front brake behavior, wheel package, tire compound, rear brake pairing, ABS / proportioning strategy, and whether the car uses OEM or custom front uprights.
2. Data Submission
For OEM knuckles, provide year, make, model, trim, current wheel size, intended use, and detailed wheel specifications. For custom uprights, motorsport hub conversions, or non-OE rotor offsets, provide CAD files, technical drawings, hub-face data, rotor mounting dimensions, or accurate bracket mounting-point measurements.
3. Engineering Review & Approval
TTSPORT confirms rotor size, caliper clearance, vehicle-specific caliper bracket geometry, rotor hat offset, brake line fittings, pad compound, and required fitment details before production begins.
If you are unsure whether your wheel, front knuckle, rotor offset, brake balance target, or brake line routing is suitable, Contact us before ordering so the engineering team can review the build details.
Installation & Break-In
- TR48 uses radial-mount, vehicle-specific caliper brackets and vehicle-specific brake line fittings.
- Choose Ø355 mm × 32 mm for lighter chassis, tight tracks, 18 in wheels, and lower thermal demand.
- Choose Ø380 mm × 32 mm for heavier chassis, fast circuits, endurance use, and higher thermal headroom.
- Standard 0–600 °C pads suit sprint sessions, HPDE, and dual-purpose street / track cars driven to events.
- Option B 0–750 °C pads suit sustained high-temperature work, time attack, and endurance racing.
- A proper bed-in cycle transfers an even layer of pad material onto the rotor face, sets initial friction, and prevents uneven deposits, vibration, and judder.
- Complete the included bedding procedure before your first hard session.
Frequently Asked Questions
What is the TR48 designed for?
The TR48 is a front-axle 4-piston monoblock big brake kit built for circuit, time-attack, drift, and rally use. It targets thermal repeatability lap after lap, a stable pedal under load, and predictable brake balance when paired with a matched rear setup.
Which rotor size and pad compound should I choose?
Choose Ø355 mm × 32 mm for lighter cars, tight tracks, and 18 in wheels, or Ø380 mm × 32 mm for heavier chassis, fast circuits, and endurance heat loads. The standard pad runs 0–600 °C with avg μ 0.38; the racing-steel option runs 0–750 °C with avg μ 0.45 for sustained high-temp work.
What wheel clearance does the kit need?
Minimum 18 in wheels are required. Caliper envelope is 258.8 mm × 157.7 mm × 75.2 mm. Wheel barrel and spoke geometry vary, so confirm clearance against the caliper profile before ordering, especially with 380 mm rotors.
Are the rotors two-piece, and are they directional?
Yes. Rotors are two-piece assemblies, internally vented, with left/right specific directional vanes. Mounting is fixed or floating depending on rotor size and vehicle application. Face options include curved slot, grain slot, wave slot, and drilled-and-slotted; the racing-steel option ships wave slot.
Is a bedding-in procedure required?
Yes. A proper bed-in cycle is required to transfer pad material evenly to the rotor face, set initial friction, and prevent uneven deposits or judder. Follow the included procedure before any hard track sessions.
Can I get this kit for my specific vehicle?
Yes. The TR48 uses radial-mount, vehicle-specific caliper brackets and vehicle-specific brake line fittings. Send your year, make, model, trim, and wheel spec through our contact page and we will confirm the correct bracket, rotor size, and line kit.
Spec your TR48 build
Send your year, make, model, trim, current wheel size, and intended use. We will confirm rotor size, bracket geometry, line fittings, and pad compound for your application.
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.1 ★★★★★
Based on 23 reviews
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Product Reviews
★★★★★ 5
Chromed out looks good
The price was a beatable installment easy
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on September 11, 2021
★★★★★ 1
Does not fit
Fitment is horrible, don’t waste your money. Tabs are already broken upon receiving. Does not hold on to hood.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on November 14, 2025
★★★★★ 3
Fit is ok
They are a definite improvement from my original 22 year old grills but they have some clear differences in quality of the chroming, if you compare oem to these side by side the oem grills look smoother. also they don't fit great at least not on my car, albeit with a bit of nudging they fit pretty close to the originals. Overall not bad for something that is a quarter of the price of the oem part
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Reviewed in the United States on July 9, 2022
★★★★★ 5
smoke free
i like it . is nice
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Reviewed in the United States on July 17, 2021
★★★★★ 4
Looks terrific - great price
I needed to replace just one, but ended up using both the left and right so that they matched. In the closeup picture you can see that the original part is chrome with black on the inside edges of the fins, where the replacement is all chrome. This is only obvious up close if you're looking for it. There is also a slight gap in the fit at the lower inside corner - so not perfect, but also not noticable at any reasonable distance. Wide shots shows both replacement parts installed.
As others have mentioned, this is not the same quality as the original BMW part - but at 1/4 of the price, it is a darn good value and has restored the look of my car.
FOR 2003 CONVERTIBLE OWNERS: This part fits the "pre-facelift" model manufactured through March 2003. I learned this the hard way, because I didn't know about the facelift that came half a year later for cabriolets than it did for hard top models. Make sure you know which side of that manufacturing date your 2003 convertible is on before ordering.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on July 24, 2023
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