Sitta Aluminium Rear Sprocket BMW M1000RR K66 (2021-2026) – 37-47T, 520 Pitch, Part 207Y

Crafted from aircraft-grade aluminium and available in eight distinctive anodised finishes, the Sitta 207Y rear sprocket is engineered specifically for the BMW M1000RR K66 — a machine that demands components as purposeful and refined as the chassis they serve. Whether you are chasing lap times or dialling in the perfect road setup, the 207Y gives you the precision, finish quality and heritage craftsmanship that Sitta has built its reputation on.

Key Features

• Premium aluminium construction delivers exceptional strength with minimal rotational mass — exactly what the high-revving M1000RR drivetrain deserves.
• Hard-anodised finish option provides significantly greater surface hardness and wear resistance than standard anodising, extending service life under sustained track use.
• Eight colour options — silver, black, hard-anodised, red, blue, orange, gold and green — allow precise aesthetic matching to your BMW's livery or personal style.
• Tooth range from 37 to 47 teeth lets you fine-tune gearing for your preferred circuit or riding discipline without changing the sprocket carrier.
• 520-pitch specification pairs with performance chain kits for reduced weight and friction compared to heavier OEM-equivalent pitches.
• Precise 5-bolt sprocket carrier interface (119 x 140 mm, 12.50 mm bolt holes) ensures a direct, play-free fit on the K66 carrier — no adaptation required.

Design, Finish and Heritage

Sitta has been producing high-quality drivetrain components for road and race use for decades, and the 207Y reflects that accumulated engineering knowledge. Every sprocket is machined to tight tolerances, and the anodised surface treatments are applied to exacting standards — not as an afterthought, but as an integral part of the product's durability story.

The hard-anodised variant deserves particular attention. Where standard anodising adds colour and a modest degree of corrosion resistance, hard anodising penetrates deeper into the aluminium substrate, creating a surface layer that resists abrasion and chain wear far more effectively. For riders who cover high mileages or who regularly use their M1000RR on track, the hard-anodised 207Y is the intelligent long-term choice.

For those where visual impact is equally important, the full palette of colours — from understated silver to vivid orange and gold — means the 207Y can complement every specification of the M1000RR, from stock to fully race-prepared.

Gearing and Performance

Selecting the right tooth count is one of the most cost-effective performance adjustments available to any M1000RR owner. The 207Y's 37-to-47-tooth range covers the full spectrum of road and track requirements.

A smaller sprocket in the 37-to-42-tooth range shortens the overall gearing, raising top speed and reducing engine rpm at motorway cruising speeds — ideal for high-speed circuits or long touring stints. Moving to a larger sprocket in the 43-to-47-tooth range increases overall gearing, sharpening acceleration response and improving drive out of tight corners, which suits technical circuits and aggressive street riding alike.

Fitment and Compatibility

The Sitta 207Y is designed exclusively for the following application:

• BMW M1000RR, model code K66, model years 2021 to 2026
• Compatible with 520-pitch chains only
• Sprocket carrier interface: 119 x 140 mm, 5-bolt pattern, bolt hole diameter 12.50 mm

Specifications