Rear-Axle Bias Control
Designed to support stable trail braking, corner entry behavior, and rear brake balance without overpowering the front axle.
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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
4.3 ★★★★★
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Product Reviews
★★★★★ 5
helped treat my sore neck
Color: White-cooling Basic, Size: Camping Pillow(Pack of 1)
This pillow — after dialing in the right amount of shredded foam — has greatly helped my sore neck. Initially, I had to remove some foam. Then I gradually added foam until it reached optimum comfort and support.
It is also CPAP-friendly — especially when I position my head near the pillow's edge. (I am a left-side sleeper.)
I like the travel size because I use a bulky hugging pillow to ease stress on my shoulder and elbow. That makes my side of the bed feel cramped if using a larger head pillow. A smaller pillow is easy to flip end-to-end in the middle of the night.
I have spent lots of money on pillows over the years, but this is the best I've ever had for relieving [1] neck pain and [2] CPAP mask seal problems. Very comfortable, supportive, and affordable.
I did not notice any unpleasant smell — and I am usually sensitive to that kind of thing.
Would highly recommend.
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Reviewed in the United States on May 7, 2026
★★★★★ 5
Love them!
Color: White-cooling Basic, Size: Queen(Pack of 2)
Love them! After 10 years with our MyPillows, they finally lost their fluff. The reviews I read of the MyPillows of today were not good; they didn’t have as much filling as they used to. These pillows remind me of how fluffy our new MyPillows were 10 years ago!! You sink right into them and can mush them however and they stay. These are way cheaper than the Coop and it’s the same concept; add or remove the filling as needed. The cooling side is a huge plus too! You won’t be disappointed with these pillows!
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Reviewed in the United States on May 22, 2026
★★★★★ 5
super smooth, silky, stays comfortable feeling. DO NOT DRY or wash with heat
Color: Blue, Size: Queen (U.S. Standard), Set name: Stretchy and Soft, Color: Blue, Size: Queen (U.S. Standard), Set name: Stretchy and Soft
I'm impressed. I have used cooling pillow cases before, and found them effective, but the cooling material have always been on just one side. These are 100% cooling material. The material is super smooth and silky feeling. It is great feeling against hair and skin (even better than my old polyester satin I was using before cooling pillowcases). The material is cool, and does not seem to get hot hot. The pillow cases are super stretchy with a small hidden zipper. They grab onto the pillow and dont loosen up. Makes my pillow look neat and clean, not sloppy from loose material. I can even have two pillows stacked and somehow despite being a smooth material, the pillows dont just slide off each other.
The cooling aspect works by not trapping heat, not allowing heat to get to the pillow and hold it there. So yeh, the pillow case will feel warm eventually but if you have a fan, or AC, or flip the pillow, then it is is truly cool. Otherwise in my experience when I use a pillow without this, the pillow just gets hot, stays hot, and even with flipping it feels hot.. because the pillow itself has trapped the heat for remainder of night. Yuck.
One thing to know and this is very important-- as I learned the hard way-- DO NOT DRY IN DRYER. DO NOT WASH IN HOT WATER. Heat will destroy the material ability to feel and stay cool. Do you want a regular heat trapping pillow case? Then go ahead and dry these in the dryer a few times and you will have a regular pillow case. HOw do I know? I bought these to replace another set (different brand, same idea, same instructions that I failed to remember). I always dried them in the dryer, and one night after having gloriously cool pillows, I noticed that my pillow was HOT night after night. It was then when looking for another set of pillow cases that I learned that they cant be exposed to heat like that. SO PLEASE, just AIR DRY.
And so, after I got these and put them on my pillows, I had a much better nights rest. I remember thinking that I wasnt waking to rearrange my pillows. They were just comfortable all night long. Sure, I'd love an even colder pillow, but our room is on the warm side. But at least I wasnt noting the hot hot pillows anymore.
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Reviewed in the United States on June 6, 2021
★★★★★ 5
A must try for hot sleepers!
Color: Blue, Size: Queen (U.S. Standard), Set name: Silky, Color: Blue, Size: Queen (U.S. Standard), Set name: Silky
If you are a hot sleeper these pillowcases are for you! Not only are they silky and beautiful, but they are cool to the touch!The Arc-Chill fabric absorbs heat and instantly cools your skin! If you are prone to insomnia, night sweats, give these a try! They come in a 2 pack and have a few different colors to try out. Highly recommend.
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Reviewed in the United States on May 27, 2026
★★★★★ 5
Freezing !
Color: Gray, Size: Queen (U.S. Standard), Set name: Stretchy and Soft
### Product Review: Avolare 2 Pack Cooling Pillow Cases
#### Overview
The Avolare 2 Pack Cooling Pillow Cases are designed to provide a cooler and more comfortable sleeping experience, especially for hot sleepers. Made with Arc-Chill fabric, these pillowcases promise to offer a cooling effect, protect hair and skin, and add a touch of luxury with their soft and silky texture. The pillowcases come in a standard gray color, suitable for standard and queen-size pillows.
#### Material and Design
**Rating: ★★★★★**
The Avolare Cooling Pillow Cases are crafted from Arc-Chill fabric, known for its high Q-max value (>0.5), indicating excellent cooling properties. The material feels incredibly soft and silky to the touch, providing a luxurious feel that enhances sleep quality. The gray color is neutral and versatile, fitting seamlessly with various bedding styles.
The design includes a hidden zipper, ensuring that the pillowcase stays securely on the pillow while maintaining a smooth and sleek appearance. The zipper is discreet and doesn’t interfere with comfort, which is a thoughtful addition to the overall design.
#### Cooling Effect
**Rating: ★★★★★**
One of the standout features of these pillowcases is their cooling effect. The Arc-Chill fabric effectively wicks away heat and moisture, making them ideal for hot sleepers or those living in warmer climates. Users have reported a noticeable difference in temperature, which contributes to a more restful and comfortable night’s sleep. This cooling property is particularly beneficial during the summer months or for individuals who tend to overheat while sleeping.
#### Hair and Skin Benefits
**Rating: ★★★★☆**
In addition to their cooling properties, the Avolare pillowcases are also beneficial for hair and skin. The smooth and silky texture reduces friction, helping to prevent hair breakage and skin irritation. This can be particularly advantageous for individuals with sensitive skin or those prone to hair damage. While the pillowcases are not a cure-all for skin and hair issues, they do contribute positively by creating a gentler surface.
#### Durability and Care
**Rating: ★★★★☆**
The Avolare Cooling Pillow Cases are easy to care for, maintaining their cooling properties and softness even after multiple washes. They are machine washable, which adds to their convenience. However, it is recommended to follow the care instructions carefully to ensure the longevity of the cooling effect and fabric quality.
#### Versatility
**Rating: ★★★★☆**
These pillowcases are designed to fit both standard and queen-size pillows, adding to their versatility. They are perfect for use in any bedroom setting, from master bedrooms to guest rooms, and can be paired with various pillow types and fillings.
#### Pros and Cons
**Pros:**
- Excellent cooling properties ideal for hot sleepers.
- Soft and silky texture is gentle on hair and skin.
- Hidden zipper design for a secure fit.
- Machine washable and easy to care for.
- Versatile fit for standard and queen-size pillows.
**Cons:**
- Cooling effect may diminish slightly with frequent washing.
- Limited color options (only available in gray).
#### Final Verdict
**Overall Rating: ★★★★☆**
The Avolare 2 Pack Cooling Pillow Cases are an excellent choice for anyone looking to enhance their sleeping experience, particularly hot sleepers. The cooling properties of the Arc-Chill fabric, combined with the soft and silky texture, provide a comfortable and luxurious feel. The hidden zipper design adds practicality without sacrificing aesthetics.
While there are minor drawbacks, such as potential diminishing of the cooling effect with frequent washing and limited color options, the overall benefits make these pillowcases a worthwhile investment. If you’re seeking to improve your sleep quality and enjoy a cooler, more comfortable night’s rest, the Avolare Cooling Pillow Cases are definitely worth considering.
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Reviewed in the United States on June 1, 2024
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