Big Brake Kit
XYZ Racing Hollow Front Brake Kit — Mercedes Benz S CLASS W221 S 420 CDI (2005-2013)
SKU: XYZ-BRK-BKF-ME-071-FRONT
- IncludesFront axle pair (2 discs + 2 calipers)
- PositionFront
- Disc Ø330–444 mm
- Caliper pots6 / 8 / 12-pot
- Lead time10–15 working days
Fits Mercedes Benz S CLASS W221 S 420 CDI (2005-2013)
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Caliper render for this kit:
The W221 S 420 CDI moves over 2,100 kg at the command of a 4.0-litre V8 diesel generating 730 Nm from low in the rev range, placing a thermal and mechanical load on the standard front brakes that most owners underestimate. Push the car hard on a fast A-road or take it to a track day and the OEM caliper specification, calibrated for refinement rather than endurance stopping, begins to feel insufficiently matched to the mass it is slowing.
The XYZ Racing front big brake kit for the W221 S 420 CDI addresses that mismatch. A matched pair of left and right two-piece floating discs reduces rotating and unsprung mass at the front axle, and pad compound can be specified from Street, Sport, or Racing grades, so the kit covers everything from a quiet road default to sustained circuit use. A wide range of caliper finishes completes the configuration.
What this brake kit does for your 2005-2013 Mercedes Benz S CLASS W221 S 420 CDI
At the W221’s kerb weight, front brake performance under repeated hard stops is not an academic concern. The two-piece floating disc lets the friction ring expand without coning, the hollow-vane construction draws air through the disc to manage heat, and the reduced rotating mass eases the work the air suspension does to maintain front wheel contact through the transition from acceleration to braking. Street is the quiet, low-dust road default for owners who want an OEM-character feel with upgraded hardware behind them; Sport raises bite and the thermal threshold for drivers using the car’s performance regularly on fast public roads; Racing is the track compound, extending the operating window for circuit use where disc temperatures exceed what road-spec friction materials are rated for. Disc faces are offered drilled or slotted at the same price, and the calipers sit visibly through the W221’s large-diameter front wheels.
About the Front Brake Kit
The two-piece floating, hollow-vane disc reduces rotational inertia the front caliper assembly must arrest with each application while maintaining full swept-area dimensions. This is a big brake kit upgrade, not a like-for-like OEM replacement, supplying larger caliper units alongside the two-piece floating rotors. The caliper is hollow-bodied as standard, light and stiff to resist flex, with an optional Hollow Racing upgrade for sustained track sessions that deletes the dust cover, is rated to 1000C, and carries a two-year warranty. Braided lines firm the pedal, and centre bells can be upgraded to two-tone anodizing in five colours or titanium at checkout. The three pad compounds span the range from a road-priority default to a fully heat-soaked track item, and caliper finish runs from the included painted colours (Red, Yellow, Gold, Black, Anodized Black) at no extra cost, through a Custom Color in any Pantone for 150 pounds, to premium polished-forged and candy options. Installation uses standard workshop tooling; no hub modification or custom adapters are required for the W221 platform.
Fitment for the Mercedes Benz S CLASS W221 S 420 CDI (2005-2013)
This kit is built to the front hub geometry and caliper mounting of the W221 S-Class in S 420 CDI specification, covering the production run from 2005 to 2013 and supplied as a left-and-right front pair. Buyers should confirm their exact variant, as the W221 was offered across multiple engine configurations and brake architecture differs between the S 420 CDI, the petrol S 420, and the inline-six S 350 variants. Checking against the chassis plate or VIN-decoded spec sheet before ordering avoids any fitment uncertainty.
What buyers also search for
- Mercedes Benz W221 S420 CDI front brake upgrade for fast road and high-speed motorway use
- W221 S-Class big brake kit with selectable Street, Sport, and Racing pad compound
- Mercedes S Class W221 brake performance solution for sustained hard driving
- XYZ Racing two-piece floating front brake kit for Mercedes W221 S 420 CDI 2005-2013
- Mercedes W221 S420 CDI caliper colour options including Red, Yellow, Gold, Black, and Anodized Black
Choose your pad compound and caliper colour from the options above, then build yours.
What’s in the kit
Front axle kit — supplied as a complete bolt-on assembly.
- 2×Two-piece floating discs — 330–444 mm: you pick the exact diameter with the "Disc size" option
- 2×Lightweight aluminium centre bells
- 2×Forged aluminium calipers — 6 / 8 / 12-pot
- 2×High-stiffness mounting brackets
- 2×Braided stainless steel brake lines
- 4×High-performance brake pads (1 set)
- 1×Fitting hardware & tools pack
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 286–380mm (front). 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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