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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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
4.1 ★★★★★
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★★★★★ 5
oh wow
Format: Kindle
I just knew there was something about Cooper! I’m wondering if he’s about to be included but damn I’m glad he’s at least not a rapist and creepy guy, he just got called on assignment and had to go! This should be interesting! She’s gonna run and then what’s his face is gonna grab her. I’m worried! Wow that was a great book and cliffhanger! Loving this!
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Reviewed in the United States on December 27, 2025
★★★★★ 5
ABSOLUTELY A MUST for Omegaverse Girls!!!
I ABSOLUTELY LOVE Jillian West and her books!!! I’m so happy I already bought book two and now I have to buy the others for the Assurance Security series!!
Not gonna lie Val kind of annoyed me at the beginning but she grew on me!! Her men are chef’s kisses!!! Holt annoys me some but I can let it slide. I already bought part two so I’m going to be reading that in between work phone calls!!!! DON’T TELL MY BOSS 😂😂😂😂
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Reviewed in the United States on September 30, 2025
★★★★★ 4
Baby bumps and bodyguards
Format: Kindle
Dark, emotional, and unexpectedly tender, Not Ready is an omegaverse romance that delivers found family feels, fierce protectiveness, and a very pregnant heroine who refuses to break. Vale’s on the run from a stalker, but lands in the arms of three private security alphas, cue the swoony tension, fake marriage twist, and slow-burn heat.
It’s a little gritty, a little soft, and a whole lot addictive. If you love protective alphas, high stakes, and heroines with quiet strength, this one’s a must-read.
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Reviewed in the United States on December 18, 2025
★★★★★ 5
Strong Omegaverse Comfort and a Attention Grabbing Plot
Format: Kindle
Jillian West never misses when it comes to Omegaverse, and Not Ready is no exception. This story was the perfect blend of cozy comfort and emotional depth while still delivering a strong plot.
Vale is such a powerful heroine, she is strong, capable, and determined but I love that she still allows her pack to love and take care of her. It’s that balance of independence and vulnerability that makes her so relatable.
The relationship dynamics were amazing: Bishop is steadfast and completely head over heels, Mercy is skeptical but protective in his own way, and Holt is the hesitant one whose slow fall is so satisfying to watch unfold.
The romance hits that sweet spot between insta-love and cautious build, keeping me hooked the entire way through. And that ending. Oh my god, the cliffhanger! I need the next book in this duet immediately.
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Reviewed in the United States on August 28, 2025
★★★★★ 5
Interesting
Format: Kindle
So I will say I enjoyed the story, for sure had its moments where it dragged but it was a great story. I really liked that omegas picked their alphas/make the pack. Normally the Alphas make it and the omega fits in with them which is great but I enjoyed this new version where all the power basically went to the omega. It was a nice change of pace. I can admit some of the weird bedroom stuff with her being pregnant was odd, it’s really not hard to do stuff when pregnant (I know I’ve had two and it’s normal and even encouraged at the end especially if you want the baby out). But I like the story as a whole and will read the second, I do hope the next one isn’t dragged bc it stopped being action or tense after she met her alphas and I don’t think it was brought up or properly done when they tried to do it. More sweet after she left.
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Reviewed in the United States on November 11, 2024