Cruisers

2026BMW R18 Big Sister

21 fields on record

The 2026 BMW R18 Big Sister is a one-off custom show bike built by WOIDWERK alongside the R12 Little Sister for BMW Motorrad Days 2025's "Speed Sisters" project. Built on the big 1802cc air/oil-cooled boxer twin (91 HP, 158 Nm), it gets a raised and narrowed 30mm tank, a floating seat with a handcrafted Targa hoop, a 20mm-raised chassis on a Wilbers shock, and brakes borrowed from the R 1300 GS - a bespoke design study rather than a catalogued production variant.

Capacity: 1802.0 ccm
Engine: Boxer, four-stroke
Gearbox: 6-speed
Wet weight: 345.0 kg
Seat height: 719 mm
Power: 91.0 HP (67.9 kW) @ 4750 RPM

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How it rides

Editorial estimate from the spec sheet - not lab tested

Off-road & trail15%

Cornering45%

City riding45%

Daily riding50%

Touring45%

Two-up30%

Track20%

Best for: Built as a striking custom statement piece blending classic cruiser presence with upgraded braking hardware, meant for boulevard cruising and show appearances rather than outright performance riding.
Built for: A big-hearted, torque-rich air-cooled boxer-style twin cruiser with deep, unhurried power delivery and a commanding, sculpted custom presence.
Not ideal for: Not for riders seeking agile cornering, off-road capability, or a lightweight, track-focused machine.

Scores are derived from the spec sheet using the same model across every bike, so they compare like for like.

Will it fit you?

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Your height

Inseam (optional)

Units

At 719mm, a rider of 175cm with a 79cm (estimated) inseam will reach the ground with both feet flat on the 2026 BMW R18 Big Sister, with a cramped knee angle of around 80 degrees and an upright riding position.

Assumes about 30mm of suspension sag once seated. This is an approximation from category-typical geometry, not a measurement of this bike or of you - sit on one before you buy.

More bikes at 750 mm or under — Short Kings →

Find bikes that fit your height →

Full specifications

Engine

Capacity: 1802.0 ccm
Power: 91.0 HP (67.9 kW) @ 4750 RPM
Torque: 162.7 Nm (16.6 kgf-m) @ 3000 RPM
Engine type: Boxer, four-stroke
Power/weight ratio: 0.2638 HP/kg (wet)
Cooling system: Oil & air

Transmission

Gearbox: 6-speed
Transmission type: Manual

Dimensions & weight

Wheelbase: 1730 mm
Overall length: 2438 mm
Overall width: 947 mm
Overall height: 1125 mm
Seat height: 719 mm
Wet weight: 345.0 kg
Fuel capacity: 15.90 litres
Dry weight: Not on record - add it

Brakes & wheels

Front brakes: Radial calipers, 320 mm discs (BMW R 1300 GS-sourced).
Front brakes diameter: 300 mm
Rear brakes diameter: 300 mm

Other

Comments: One-off custom show bike built by [WOIDWERK] for BMW Motorrad Days 2025 ("Speed Sisters" project) - raised/narrowed tank (+30mm), floating seat with Targa hoop, raised chassis (+20mm), upgraded R1300GS-sourced radial brakes (documented). No
Comments: One-off custom show bike built by [WOIDWERK] for BMW Motorrad Days 2025 ("Speed Sisters" project) - raised/narrowed tank (+30mm), floating seat with Targa hoop, raised chassis (+20mm), upgraded R1300GS-sourced radial brakes (documented). No standalone spec sheet published; engine figures above are the unmodified base BMW R18 production specs.

Compiled from manufacturer documentation and user contributions, corrected on an ongoing basis. Spotted something wrong? Tell us.