Rear-Axle Bias Control
Designed to support stable trail braking, corner entry behavior, and rear brake balance without overpowering the front axle.
Shipping Estimate
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Ships within 48 hours · Estimated delivery Jul 8 - Jul 13
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Description
Circuit Racing TR49 Rear Wheel 4-Piston Big Brake KitRacing Series Circuit Rear Axle 4 Piston TR49 Circuit Racing Rear 4 Piston Big Brake Kit The Circuit Racing TR49 is a rear axle 4 piston big brake kit built for circuit work, time attack, and endurance use. A monoblock forged caliper, two piece floating rotors, and racing pad compounds deliver consistent pedal feel and thermal repeatability lap after lap. Why Builders Choose the TR49 Rear brake balance is what keeps a chassis stable under trail
Racing Series · Circuit · Rear Axle · 4-Piston
TR49 Circuit Racing Rear 4-Piston Big Brake Kit
The Circuit Racing TR49 is a rear-axle 4-piston big brake kit built for circuit work, time attack, and endurance use. A monoblock forged caliper, two-piece floating rotors, and racing pad compounds deliver consistent pedal feel and thermal repeatability lap after lap.
Why Builders Choose the TR49
Rear brake balance is what keeps a chassis stable under trail braking and corner entry. The TR49 pairs 28 mm and 34 mm staggered pistons with a 30.80 cm² total piston area to give a controllable rear bias without overpowering the front. Combined with a 355 or 380 mm rotor, it lets you dial in proportioning for slicks, R-comps, or street tires.
Monoblock Forged Caliper
Monoblock forged aluminum caliper, 2.40 kg per side, built for stiffness and repeatable pedal response.
Staggered 4-Piston Bore
28 mm × 2 and 34 mm × 2 piston layout supports even pad wear and progressive bite.
Racing Piston Package
Racing pistons without dust boots are designed for high-temperature service and fast race-weekend inspection.
Two-Piece Rotor Platform
Ø355 or Ø380 mm × 32 mm two-piece internally vented rotors with directional vanes.
Race-Weekend Serviceability
Replaceable iron rings, top-access pad changes, open-back pistons, and accessible bleeders support real pit workflow.
Technical Specifications & Kit Options
| Brake Caliper | ||
|---|---|---|
| Series | Racing Series — Circuit | |
| Model / Application | TR49 | |
| Axle Position | Rear | |
| Piston Count | 4-piston | |
| Piston Type | Racing pistons without dust boots | |
| Piston Diameter | 28 mm × 2 / 34 mm × 2 | |
| Caliper Dimensions | 258.8 mm × 157.7 mm × 75.2 mm | |
| Total Piston Area | 30.80 cm² per caliper | |
| Manufacturing Process | Monoblock forged aluminum body | |
| Net Weight | 2.40 kg per caliper, without pads | |
| Surface Finish | Nickel-plated | |
| Custom Color | Not available on this caliper | |
| 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 | Rear | Rear |
| 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, by size and application | Fixed or floating, by size and application |
| Directional Design | Yes — left/right specific | Yes — left/right specific |
| Rotor Face Pattern | Curved slotted / Grain Slot / Wave Slot / Drilled and slotted | Wave Slot |
| Brake Pad Options | ||
| Pad Option | Standard | Option B Racing |
| Compatible Rotor Material | Iron / steel rotors only | Iron / steel rotors only |
| Operating Temperature Range | 0–600 °C | 0–750 °C |
| Average Friction Coefficient | μ ≈ 0.38, varies with temp, pressure, rotor | μ ≈ 0.45, varies with temp, pressure, rotor |
| Best Use | HPDE, autocross, aggressive street use | Sustained circuit and endurance sessions where heat soak is the limiting factor |
| Lines, Brackets & Service | ||
| Brake Line Construction | Three-layer reinforced | |
| Brake Line Material | PTFE inner liner / SUS304 stainless braid / PVC outer sheath | |
| Caliper Mounting Type | Radial mount with vehicle-specific caliper brackets | |
| Caliper Brackets | Vehicle-specific caliper brackets | |
| Brake Line Fitting Type | Vehicle-specific; caliper-side and chassis-side fittings vary by application | |
| Bedding-In Procedure | Required before track use | |
Rear pad selection should typically run a half-step softer or cooler than the front to maintain stable rotation under brake. Match Option B rear pads with similar or higher-temp front pads to keep the car balanced.
Package List
Calipers ×2
2 × TR49 rear monoblock forged 4-piston calipers with nickel-plated finish.
Brake Pads
Brake pads for both rear calipers, selected from 0–600 °C standard compound or 0–750 °C Option B racing compound.
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
Three-layer stainless-steel braided rear brake lines with PTFE inner liner, SUS304 braid, and PVC outer sheath.
The Bespoke Engineering Process
Every TR49 rear circuit racing system is engineered around the vehicle’s rear knuckle, hub location, rotor hat offset, wheel barrel, spoke clearance, brake line routing, parking brake provision, and front-to-rear brake balance 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 trail braking, corner entry, and long-session heat.
1. Technical Consultation
We review the chassis, rear suspension and knuckle setup, competition use, target rear brake behavior, front brake pairing, wheel package, tire compound, ABS / proportioning strategy, parking brake requirement, and whether the car uses OEM or custom rear uprights.
2. Data Submission
For OEM knuckles, provide the vehicle information, wheel specs, wheel offset, and spoke clearance data. For custom knuckles, motorsport hub conversions, or non-OE rotor offsets, provide CAD files, drawings, hub-face data, rotor mounting dimensions, or accurate bracket mounting-point measurements.
3. Engineering Review & Approval
TTSPORT reviews the submitted data, confirms caliper clearance, vehicle-specific caliper bracket geometry, rotor hat offset, parking brake approach, and brake line routing before production begins.
If you are unsure whether your wheel, rear knuckle, rotor offset, parking brake layout, or brake line routing is suitable, Contact us before ordering so the engineering team can review the build details.
Installation & Break-In
- Every TR49 rear kit ships with vehicle-specific caliper brackets and brake lines.
- Two-piece rotors allow iron ring replacement without buying new hats.
- Pads change from the top with a single retainer pin.
- Open-back pistons allow fast inspection and seal service.
- Standard race fluid bleeders are accessible with the caliper on the car.
- Confirm wheel offset, spoke profile, hub specs, rotor offset, and line routing before production.
- A proper bedding procedure is required to transfer pad material evenly to the rotor face before track use.
Frequently Asked Questions
Will the TR49 rear kit clear my wheels?
The kit requires an 18-inch or larger wheel. Clearance also depends on wheel offset and spoke profile. Send your wheel specs with your order and we'll confirm before shipping.
Should I match this with a TTSPORT front BBK?
Yes. Rear-only upgrades can shift bias rearward and cause instability. Pair the TR49 with a matching front kit sized for your vehicle to keep brake balance correct.
Which rotor size should I choose, 355 or 380 mm?
Ø355 mm is the lighter, more wheel-friendly option and works for most rear setups. Ø380 mm adds thermal capacity for endurance and heavier cars where the rears do more work.
Do I need to bed the pads in?
Yes. A proper bedding procedure is required to transfer pad material evenly to the rotor face. Skipping it causes judder, uneven deposits, and reduced pad life.
Can the calipers be color-customized?
The TR49 ships in nickel-plated finish. Custom color/anodizing is not available on this caliper.
Does the kit include parking brake provision?
The TR49 is a service-brake caliper. Vehicles with integrated rear parking brakes typically retain the OEM e-brake setup via drum-in-hat rotors or a separate e-brake caliper, depending on application. Confirm with our team for your specific car.
Build Your TR49 Rear Kit
Send your vehicle and wheel details and we'll spec the right rotor size, pad compound, rotor hat offset, and bracket package for your program.
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
Great usability
I prefer this version over the non-foldable stick, as this one I can fit into my bag and carry it out easily. Great size and has a locking feature to prevent it from folding up when throwing. Highly recommend, my dogs love fetch and it is hard to chew if they get their hands on it.
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Reviewed in the United States on September 13, 2025
★★★★★ 5
Holds up! Good thrower!
Good quality! Throws far! Love this brand!
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Reviewed in the United States on April 10, 2026
★★★★★ 4
Almost Perfect
If you’ve ever seen these things, the foldable ones are just as good as the standard ones. I just wish when you folded it up there was a way to lock it into that position. When you unfold it to play, you lock it into place with the orange locking slide so it doesn’t fold up on you. But when you’re done playing and fold it up, there’s no way to lock it into that position, it can keep unfolding if you carry it around with you, plus the orange locking slide keeps sliding up and down. It’s not a huge deal, but they could’ve made it better.
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Reviewed in the United States on April 29, 2026
★★★★★ 5
Helpful
I’ve used Chuckit ball launchers, this one is foldable, great for my back pack when camping with my dog
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Reviewed in the United States on February 27, 2026
★★★★★ 5
Great to keep your dog entertained
Color: Blue
Great toy my 13 month old cane corso absolutely loved it and it kept her entertained forever except she has an extremely strong bite so she was figuring out a way to split it apart so I had to take it away -it’s extremely strong, but not strong enough for the bite of a cane corso but any other dog would love it. I just wish my dog didn’t have such a strong bite and would be able to keep enjoying it since it is a little expensive the only problem with it is that I thought the remote shuts it off, but then her bites were making it come back on, so I don’t know if it was my dog or the toy just doesn’t stay off until you turn it on.
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Reviewed in the United States on March 1, 2026