Rear-Axle Bias Control
Designed to pair with a larger front BBK and help set rear brake bias on track, time-attack, drift, or endurance builds.
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Ships within 48 hours · Estimated delivery Aug 16 - Aug 21
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Description
Circuit Racing TR61 Rear Wheel 6-Piston Big Brake KitRacing Series Circuit Rear Axle 6 Piston TR61 Circuit Racing Rear 6 Piston Big Brake Kit The TR61 Rear 6 Piston Big Brake Kit is a Racing Series Circuit caliper engineered for track, time attack, and endurance use. Monoblock forged aluminum body, six racing pistons without dust boots, and a two piece directional rotor package built for thermal repeatability and predictable rear brake balance. Why Builders Choose the TR61 The TR61 is a rear axle race
Racing Series · Circuit · Rear Axle · 6-Piston
TR61 Circuit Racing Rear 6-Piston Big Brake Kit
The TR61 Rear 6-Piston Big Brake Kit is a Racing Series — Circuit caliper engineered for track, time-attack, and endurance use. Monoblock forged aluminum body, six racing pistons without dust boots, and a two-piece directional rotor package built for thermal repeatability and predictable rear brake balance.
Why Builders Choose the TR61
The TR61 is a rear-axle race caliper designed to pair with a larger front BBK and give you a tunable rear brake bias. The 6-piston layout uses a staggered bore configuration, 27 / 28.5 / 32 mm, to load the pad evenly across its length, reducing taper wear and extending pad life under repeat heavy braking. Piston seals run open, no dust boots, for faster heat rejection and easier service between sessions.
Monoblock Forged Caliper
Monoblock forged aluminum body delivers high stiffness and low flex under load.
Staggered 6-Piston Bore
27 mm × 2 / 28.5 mm × 2 / 32 mm × 2 piston layout helps load the pad evenly for consistent pedal feel.
Two-Piece Directional Rotors
Ø355 or Ø380 mm × 32 mm two-piece directional rotors, internally vented, fixed or floating depending on rotor size and application.
Standard or Racing Package
Standard 0–600 °C pad and rotor package for club days and HPDE, or Option B 0–750 °C package for time-attack, endurance, and sustained heat cycles.
Race-Service Hardware
Stainless braided lines, radial brackets, open racing pistons, and required bedding instructions support a real track workflow.
Technical Specifications & Kit Options
| Brake Caliper | ||
|---|---|---|
| Series | Racing Series — Circuit | |
| Model / Application | TR61 | |
| Axle Position | Rear | |
| Piston Count | 6-piston | |
| Piston Type | Racing pistons, no dust boots | |
| Piston Diameter | 27 mm × 2 / 28.5 mm × 2 / 32 mm × 2 | |
| Caliper Dimensions | 277.8 mm × 167.4 mm × 80.3 mm | |
| Total Piston Area | 40.28 cm² per caliper, all pistons combined | |
| Construction | Monoblock forged aluminum | |
| Net Weight | 2.90 kg per caliper, without pads | |
| Surface Finish | Nickel-plated | |
| Custom Color | Not available on this model | |
| Recommended Wheel Size | 18 in or larger | |
| Recommended Rotor Size | Ø355–380 mm × 32 mm | |
| Brake Rotor Options | ||
| Rotor Option | Standard Race | Option B — Endurance |
| Rotor Material | Heat-treated high-carbon cast iron | Racing-grade heat-treated high-carbon cast iron |
| Rotor Dimensions | Ø355 or Ø380 mm × 32 mm | Ø355 or Ø380 mm × 32 mm |
| Construction | Two-piece, internally vented | Two-piece, internally vented |
| Rotor Hats | Application-specific alloy rotor hats | Application-specific alloy rotor hats |
| Mounting | Fixed or floating, depending on rotor size and application | Fixed or floating, depending on rotor size and application |
| Directional Design | Yes — left/right specific | Yes — left/right specific |
| Rotor Face Pattern | Curved slot / Grain Slot / Wave Slot / Drilled & slotted | Wave Slot |
| Best Use | HPDE, autocross, club racing | Time-attack, endurance, sustained heat cycles |
| Brake Pad Options | ||
| Pad Option | Standard Race | Option B — Endurance |
| Compatible Rotors | Iron / steel rotors only | Iron / steel rotors only |
| Operating Temperature Range | 0–600 °C | 0–750 °C |
| Average Friction Coefficient | μ ≈ 0.38 | μ ≈ 0.45 |
| Recommended Use | Club days, HPDE, mixed street / track | Endurance, time-attack, back-to-back race sessions |
| Lines, Brackets & Service | ||
| Brake Line Construction | Three-layer reinforced | |
| Brake Line Material | PTFE inner / SUS304 stainless braid / PVC outer | |
| Caliper Mounting | Radial mount with vehicle-specific caliper brackets | |
| Caliper Brackets | Vehicle-specific radial brackets | |
| Brake Line Fittings | Vehicle-specific, caliper-side and chassis-side | |
| Bedding-In Procedure | Required before track use | |
Nickel-plated finish is fixed — chrome and color changes are not available on this model. Rotor diameter and pad compound should be selected according to front BBK setup, rear brake bias target, wheel clearance, and event format.
Package List
Calipers ×2
2 × TR61 rear monoblock forged 6-piston calipers with nickel-plated finish.
Brake Pads
Brake pads for both rear calipers, selected from Standard Race 0–600 °C or Option B Endurance 0–750 °C package.
Brake Rotors ×2
2 × two-piece internally vented rear rotors, Ø355 or Ø380 mm × 32 mm, left/right specific.
Caliper Brackets ×2
Vehicle-specific radial caliper brackets for correct rear caliper alignment.
Rotor Hats ×2
Application-specific alloy rotor hats matched to rear hub location and rotor offset.
Brake Hoses ×2
Stainless braided rear brake lines with PTFE inner, SUS304 stainless braid, and PVC outer sheath.
The Bespoke Engineering Process
Every TR61 rear circuit racing system is engineered around the vehicle’s rear knuckle, hub location, rotor hat offset, wheel barrel, spoke clearance, front BBK setup, brake line routing, and rear brake bias target. The goal is not a generic universal fit; the goal is a rear brake package that works with your chassis geometry and gives the driver repeatable pedal behavior under sustained track heat.
1. Technical Consultation
We review the chassis, rear suspension and knuckle setup, motorsport use, target rear brake behavior, front BBK setup, wheel package, tire compound, ABS / proportioning strategy, and whether the car uses OEM or custom rear uprights.
2. Data Submission
For OEM knuckles, provide chassis details, wheel specs, front brake setup, and rear hub information. For custom knuckles, 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, vehicle-specific caliper bracket geometry, rotor hat offset, brake line routing, front/rear bias target, and bedding requirements before production, bench-fit, and shipment.
If you are unsure whether your wheel, rear knuckle, rotor offset, front BBK setup, or brake line routing is suitable, Contact us before ordering so the engineering team can review the build details.
Installation & Break-In
- Every TR61 rear kit ships with vehicle-specific radial brackets and braided lines cut to length.
- Rotor diameter, Ø355 or Ø380 mm, is confirmed during the engineering review.
- Standard or Option B pad and rotor package should be matched to your event profile and front BBK setup.
- Minimum wheel size is 18 in, but spoke profile and offset still affect final clearance.
- Racing pistons without dust boots are intended for motorsport and track use, with regular inspection between sessions.
- Proper bed-in is required before hard use to transfer pad material and stabilize the friction surface.
- Instructions ship with the kit and must be followed before first hot session.
Frequently Asked Questions
Is the TR61 a front or rear caliper?
Rear axle. The TR61 is designed to pair with a larger front BBK to set rear brake bias on a track or drift build.
What rotor size should I run?
Ø355 × 32 mm or Ø380 × 32 mm, both in two-piece floating or fixed construction depending on the application. We confirm sizing during the fitment review.
What's the difference between Standard and Option B?
Standard uses high-carbon iron rotors with a 0–600 °C pad window and μ 0.38. Option B uses racing-grade iron rotors with Wave Slot face and a 0–750 °C pad window with μ 0.45 for endurance and sustained heat.
Will it clear my wheels?
Minimum 18-inch wheels. Wheel spoke profile and offset still matter — send wheel specs and we'll confirm clearance before production.
Are these calipers street legal?
The TR61 uses racing pistons without dust boots and race pad compounds. It's intended for motorsport and track use. For street/track dual-use, ask about pad compound options.
Is bedding-in required?
Yes. Proper bed-in is required before hard use to transfer pad material and stabilize the friction surface. Instructions ship with the kit.
Spec Your TR61 Rear Kit
Talk to our brake engineers about rotor size, pad compound, rotor hat offset, caliper bracket geometry, and front/rear bias matching for your build.
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
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★★★★★ 3
Nice, but ultimately unusable
Size: One Size, Color: Brown
The credit card slots are too deep leaving very little of the card sticking out. If you use all of the credit card slots, the thing gets so tight. It is fierce difficult to get the cards out.
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Reviewed in the United States on February 2, 2025
★★★★★ 5
Great front pocket wallet/money clip
Size: One Size, Color: Brown
This was for my husband’s birthday. He loved it. He’s also a bit picky with his front pocket wallet/money clips. He doesn’t like the money clips with the magnet. This very good and holds a good wad of cash or a few bills without it being loose or him afraid he’s going to loose something. Also has the window for his license. Holds plenty of cards as well.
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Reviewed in the United States on October 14, 2025
★★★★★ 5
Gift for dad
Color: Vintage Cognac TF02
This leather trifold wallet is both stylish and functional. The leather feels high-quality and softens nicely with use, giving it a classic, worn-in look over time. It has plenty of compartments for cards, cash, and IDs, keeping everything organized without feeling bulky in my pocket. The stitching is solid, and the wallet feels durable enough to last for years. Overall, it’s a practical, elegant choice for anyone who wants a reliable wallet that combines functionality with timeless style.
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Reviewed in the United States on December 4, 2025
★★★★★ 5
well made wallet
Color: Cognac Vintage TF03
seems to be a good solid product for the money
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Reviewed in the United States on May 6, 2026
★★★★★ 5
I love it!!!!
Color: Vintage Cognac TF02
This is a really nice wallet. Leather looks and feels very high quality, and you can't beat the price.
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Reviewed in the United States on April 9, 2026