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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Ships within 48 hours · Estimated delivery Aug 14 - Aug 19
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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
4.6 ★★★★★
Based on 6 reviews
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Product Reviews
★★★★★ 5
Bounces good
Size: Large (Pack of 1), Color: Multi, Size: Large (Pack of 1), Color: Multi
My dog loves this ball ,,the ball is a thick rubber ,and is flexible that even my little dog can carry it in his mouth, it does bounce really good , I recommend this ball if your dog likes chasing after balls. If you have a fenced in yard I do not recommend bouncing it hard because it might go over the fence.
UPDATE I have had this ball a few days now and my dog likes to chew on his toys and tear them apart, one time he had a tennis ball and he managed to tear it apart but this ball he has yet to tear apart,
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 5, 2026
★★★★★ 5
Chuck It Balls!! Best Loved Fetch ball by my Dog!!
Size: Large (Pack of 1), Color: Multi, Size: Large (Pack of 1), Color: Multi
Chuck It large Whistle balls,
Absolutely love these great rubber balls, I think there is at least 20-25 balls all over my house, yard and in my boys toy box.
At least one is trapped until fall on our ravine hill side, they do bounce high and off his snout for more travel time.!! (Over the fence and into ravine)
I subscribe and save getting usually 1 or 2 a month, Really… makes it easy to find one, when they are everywhere!!😜
They are usually blue in color, once in awhile I get an orange one (which I prefer, easier to find in the grass/bushes)
These do have a light whistle sound when throwing and my dog will change direction hearing where they are headed. These balls are very durable and last a very very long time. Actually I don’t think one has worn out.. lost yes….
Definitely get the large size, perfect for a med to large dog to play fetch forever!!
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 15, 2025
★★★★★ 5
Love this ball!
Size: Large (Pack of 1), Color: Multi
My doberman and her dog friends love this large high bounce rubber fetch ball! She loves to chew it endlessly between throws and her Rottweiler buddy loves to do the same because it has a hole through it. I definitely recommend the large 3 inch ball for larger dogs.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on November 15, 2025
★★★★★ 4
The orange ones are perfect!
Size: Medium (Pack of 2), Color: Assorted
I wish I could give 4 1/2 stars but it isn't possible.
The reason why I don't give 5 stars is because no one sells these in a 2 pack of just orange balls. I was able to find blue only but not orange only. I have a pitbull and so does my good friend. We take our dogs out all the time and they absolutely love chasing these balls.... The orange ones to be exact. They will not play with or bring the blue balls back. They are a waste. I had to buy 2 packs to keep the oranges. I'm taking the blue ones to the local dog park and just dropping them off.
Now to the reason these balls deserve 5 stars: They are super easy to throw and they also make a slight whistling noise when you throw them because of the holes. They are real easy to wash due to the material. Also, they are pretty indestructible. The only reason I'm ordering more is due to them being lost. Our dogs have never torn them apart. I'm sure they could if we let them, but we use these for chase, not as chew toys. My friend also tied a rope through one of the balls to throw and retrieve with the rope. He uses this as a fun indoor toy.
These do not float in water but I buy other chuckit balls for that purpose. They have the orange balls with the blue stripe which work great in pools.
The balls are awesome and I keep coming back for more. Hopefully your dogs like the blue balls.
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Reviewed in the United States on December 8, 2015
★★★★★ 5
Worth the money
Size: Medium (Pack of 2), Color: Assorted
I've had several sizes of Chuck-It ball launchers for years but had resisted buying the balls to go with them because I had about 50 tennis balls already that cost only pennies apiece and these were quite a bit more expensive. But, I got tired of the dogs chewing up the tennis balls. I'd start a ball throwing session with a brand new ball and for the first few throws it would sail through the air and the dogs would have to work to retrieve it. However on the way back, their jaws would work it, chomp-chomp-chomp. And when they returned to me, they'd want to stand there and chomp some more, despite my command to "Drop it!" Within 30 minutes, the brand new ball would have a hole in it and then instead of sailing several football fields through the air, then bouncing over a couple of trees, I'd throw it and it would piddle unenthusiastically to the end of the driveway before falling to the ground with a sulky thud, not even bothering to bounce.
So - I finally grew tired of going through a ball every time I play with the dogs - which is everyday - and ordered these chuck-it balls. They are the same size as a tennis ball but made of a rubber-like material (not silicone) and after several months of use, have no wear and tear on them at all. The dogs can exercise their gums on them all the way back to me - throw after throw - and the ball still flies the same distance each time, and bounces satisfyingly upon contact with the ground.
The description says "colors may vary" but the first packet I ordered were blue and orange as pictured. Unfortunately my dog lost the orange one the first time we used it. She got thirsty and ran down to our pond for a drink, dropped the ball in the pond and it hasn't been seen since. It is dense enough it doesn't float as a tennis ball might, and by now is probably so covered in mud and slime that I wouldn't recognize it if I tripped over it. Lesson learned: we don't throw the ball in the pond pasture any more.
After losing the orange ball, I ordered a second packet of the balls so that I would always have a spare. The second packet is also blue and orange. So while colors may vary, in my experience so far, they haven't (which doesn't matter to me or the dogs).
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Reviewed in the United States on March 1, 2015
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