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 Jul 5 - Jul 10
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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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★★★★★ 5
delightful read
Format: Kindle
What a delightful read. The characters are awesome, the plot was so good, I loved it. I was intrigued and it kept me wanting more. Told in multiple pov, the book sucks you in and doesn’t let go. I cannot wait to read the next book.
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Reviewed in the United States on January 30, 2025
★★★★★ 4
not bad
Format: Kindle
I loved the plot of this book. The characters just didn’t have a lot of depth. The connections and “love” just weren’t communicated very well in the writing. The author didn’t write the sweet psycho trope very well at all either. Lachlan was just a mess of a character.
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Reviewed in the United States on November 17, 2023
★★★★★ 5
A Beta Worth Rooting For
Format: Kindle
In Spare, Violet Fox flips the omegaverse on its head, giving us a Beta heroine determined to make her mark. Joining the Beta Trials to support her sick father, she's thrown into a pack that doesn't want her, especially the possessive Alphas.
But here's the twist: their sweet Omega turns out to be her scent match. Cue the angst, forbidden tension, and a slow-burn romance that will make your heart ache in the best way.
Violet Fox delivers an emotional, refreshing take on the genre, proving Betas aren't "spares." They're stars.
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Reviewed in the United States on January 10, 2025
★★★★★ 5
Beta, Alpha, Omega oh my!
Format: Kindle
Omegas are precious and given to Alphas & their packs... but the Betas want in too. To this end, the Beta government is rolling out its trial of assigning a Beta to each Alpha-Omega pack. But forcing a Beta into a pack where they are not wanted will not end well... Of course, no one expected the Omega to fall for the assigned Beta. Great read and cliffhanger
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Reviewed in the United States on February 15, 2025
★★★★★ 3
A familiar story, just with…..less.
Format: Kindle
So, as other reviewers make clear, this is very similar to Pack Darling and The Beta. It’s much closer aligned with The Beta, in plot and maybe more like Pack Darling with characters.
That being said, I don’t hate this…..but it wasn’t great either. It’s both books mentioned but just….less. Less angst, less emotion, less feeling. The plot feels very half fleshed out, and the “bad guy” feels underwhelming. I didn’t really feel any real emotions from and of the male leads, except maybe Oliver. The others fell sorta flat for me. And Mika makes herself out to be this big bad ass straight outta training and then we never see it from here again with the one fitting room incident as the exception.
SPOILER:
The whole, “Oh, I’m actually probably an Omega, but I don’t wanna be but I do actually wanna be but no one can ever know my secret that I do nothing to hide “ thing fell so flat. She never commutes to believing she was secretly an omega, but also mentions her “secret” a lot. It just felt so manufactured.
I’m intrigued enough to read part 2 and see how the author closes everything out, but this is not one I’ll recommend or ever come back to.
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Reviewed in the United States on February 13, 2024