
XYZ Racing Hollow Rear Brake Kit — Audi S4 B5 (1997-2002)
SKU: XYZ-BRK-BKR-AU-020-REAR
- IncludesRear axle pair (2 discs + 2 calipers)
- PositionRear
- Disc Ø380–421 mm
- Caliper pots8-pot
- Lead time10–15 working days
Fits Audi S4 B5 (1997-2002)
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Caliper render for this kit:

The B5 S4 carries its 2.7-litre biturbo V6 slung out ahead of the front axle, and that nose-heavy quattro layout puts most of the braking workload on the front corners while the rears go cold and underused. This XYZ Racing hollow rear brake kit for the Audi S4 B5 exists to bring the back axle back into the conversation: more rear bite to settle the car on corner entry and to stop the fronts cooking on a long descent or a repeat-stop fast road run.
Built around a two-piece floating rotor to shed unsprung and rotating mass, the kit is offered with Street, Sport and Racing pad compounds so the rear axle can be matched to how the car is actually used. It is a rear-specific upgrade for a chassis that famously asks a lot of its brakes once the RS4 turbos, a remap and 350-plus horsepower enter the picture.
What this brake kit does for your 1997-2002 Audi S4 B5
Get the rear axle working harder and the whole car feels more composed under braking, with the B5’s tendency to wash wide into a turn easing when the back tyres are sharing the load. The two-piece floating rotor reduces rotating mass at the corner, which sharpens initial response and helps the brakes recover heat between stops. With three pad compounds, you can run a quiet, dust-friendly Street pad for the daily commute, a Sport compound for spirited B-road work, or step up to the Racing compound for track sessions where the standard S4 setup fades. Braided lines hold a firm pedal as temperatures climb. Caliper finish is yours to specify, from Red, Yellow, Gold, Black or Anodized Black at no extra cost through to a custom Pantone colour, so the upgrade reads as deliberate behind the wheels rather than an afterthought.
About the Hollow rear brake kit
The two-piece floating rotor is the defining feature here: the disc cuts weight without sacrificing the thermal mass needed to absorb the heat a 1.6-tonne quattro generates under hard use, and its hollow internal vanes route cooling air through the casting. The forged caliper is hollow-bodied as standard. Less rotating mass at the wheel means quicker spin-up and brake response, and lower unsprung weight that the suspension no longer has to fight. The pad compound options span Street for quiet, low-dust road duty, Sport for a firmer everyday bite with better fade resistance, and Racing for sustained high-temperature track work. Caliper colours run Red, Yellow, Gold, Black and Anodized Black, with a custom Pantone option. Braided lines are included, discs come drilled or slotted at the same price, and the centre bell can be upgraded to two-tone anodized in five colours or titanium. As a rear kit it is designed to pair with a front upgrade or to redress a front-biased, tuned S4 that has outgrown its factory rear discs.
Fitment for the Audi S4 B5 (1997-2002)
This kit is built for the Audi S4 B5 across the 1997 to 2002 model years, the 2.7T biturbo quattro generation. It is a rear-axle fitment, a pair of rear calipers and discs; confirm your build before ordering and choose pad compound and caliper colour to suit how you drive the car.
What buyers also search for
- Audi S4 B5 rear big brake kit for the tuned 2.7T quattro
- S4 B5 two-piece floating rotor upgrade to cut rotating and unsprung mass
- Audi S4 B5 rear brake pads in Sport and Racing compound options
- B5 S4 rear brake upgrade to balance a front-heavy quattro
- Audi S4 B5 caliper colour choices including custom Pantone finishes
Pick your pad compound and caliper colour and configure your S4 B5 rear kit using the options above when you order.
What’s in the kit
Rear axle kit — supplied as a complete bolt-on assembly.
- 2×Two-piece floating discs — 380–421 mm: you pick the exact diameter with the "Disc size" option
- 2×Lightweight aluminium centre bells
- 2×Forged aluminium calipers — 8-pot
- 2×High-stiffness mounting brackets
- 2×Braided stainless steel brake lines
- 4×High-performance brake pads (1 set)
- 1×Fitting hardware & tools pack
Parking brake: OE handbrake not retained — a hydraulic handbrake is required.
Choosing your spec
Every kit is built to order around the choices you make above. Here is what each option actually changes, so you can spec yours with confidence.
Brake pads — Street, Sport or Racing
Every kit ships with a full set of high-performance pads; the compound is your call.
Street is the right default for fast-road driving — a strong, progressive cold bite with low noise, low dust and long disc life. Sport raises the working temperature and adds bite and fade resistance for hard road use and the occasional track day, while still behaving on a cold morning. Racing is a track compound built for sustained abuse: huge fade resistance and bite once heat is in it, at the cost of more noise and dust when cold. Match the pad to how hard you actually use the brakes — there is no benefit to a race pad that never gets up to temperature.
Caliper grade — Hollow vs Hollow Racing
Hollow is the standard caliper on every kit: a hollow-body forged caliper, lighter than a solid one, fitted with a dust cover and backed by a 5-year oil-leak warranty. For most fast-road and spirited track use it is all the caliper you need.
Hollow Racing is the track-grade upgrade. It runs the same hollow body but without a dust cover (so there is nothing to melt at sustained high temperature), uses a twin-metal piston that isolates heat travelling from the disc to the oil seal, and is rated to 1000°C. Available 330–356mm (rear). Warranty is 2 years on oil leaks and 10 years on appearance. Built for professional racing and repeated track days.

Caliper colour & finish
Painted colours (Red, Yellow, Gold, Black, Anodized Black) are included at no cost. Want an exact match to your car? Custom Color (+£150) paints the calipers to any Pantone code you supply (15–20 day lead time).
Polished Forged finishes are the flagship: a forged caliper given a mirror-polished surface treatment that shifts colour with the viewing angle. Beyond the looks, the polished surface dissipates heat better, resists rust and stands up to the weather. Choose Titanium (neochrome, +£350), Polished Gold (+£300) or Polished Silver (+£250). They look their best paired with a titanium centre bell. Care: clean only with a dilute neutral cleaner or water.
Candy colours (+£200) use a deep candy-paint and polishing process for a mirror-reflection, boutique finish — pick Teal, Blue, Red or Orange (shown below right).


Centre bells
The centre bell is the CNC-machined aluminium hat that joins the disc to the hub. The standard anodized centre bell is included. The Two-tone bell (+£200) adds an anodized accent ring — choose Red, Yellow, Orange, Purple or Silver right here at checkout. The Titanium centre bell (+£500) is a forged titanium bell (bolts not included) that finishes off the polished-forged look.

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