Dimension 27.5

The Ridgeback Dimension 27.5 is designed to bridge the gap between children's bikes and full-sized adult machines, offering an ultra-lightweight hybrid platform tailored for growing riders aged 11 and up (144cm to 162cm tall). Built around a 6061 aluminium frame and matching rigid aluminium fork, it weighs in at just 10.7 kg (23.6 lbs), making it significantly easier to pedal, steer, and manoeuvre than typical heavy youth bikes. Available in vibrant finishes like "Bengal Blue" or "Greenwich Green", the low-standover frame gives developing cyclists instant confidence when mounting, dismounting, and navigating daily rides.

Spec’d specifically around youth ergonomics, the Dimension 27.5 incorporates narrow 19mm grip diameters for smaller hands, short-reach adjustable Promax brake levers, and a low Q-factor 140mm alloy crankset for natural pedaling efficiency. Powering the ride is Shimano’s modern 8-speed Shimano Essa drivetrain featuring a wide-range 11-45T cassette, ensuring young cyclists can spin easily up steep hills and keep pace on family adventures. Rolling on full-size 27.5x1.95" Nutrak Speedster tires complete with flat-resistant belts and reflective sidewalls, this versatile machine is built for school commutes, park paths, and light gravel exploration.

Specifications Breakdown

Frameset & Cockpit

• Frame: Lightweight 6061 Aluminium, Low Standover, Internal Routing.

• Fork: Lightweight Rigid Aluminium, 1 1/8" Steerer.

• Handlebar: Alloy, 640mm width, 40mm rise, 10° sweep, scaled 19.0mm grip diameter.

• Stem: Alloy, 40mm extension, 10° rise, 25.4mm clamp.

• Grips: Velo Kraton Rubber, 19.0mm ID with locking collar.

• Headset: Upper ZS44/28.6, Lower ZS44/30.

• Seatpost: All-Aluminium, 27.2 x 350mm.

• Saddle: Madison Soft PU Foam Youth Saddle.

Drivetrain & Brakes

• Rear Derailleur: Shimano Essa RD-U2000-8 SG, 8-Speed (includes derailleur guard).

• Shifter: Shimano SL-M315 Trigger Shifter, 8-Speed.

• Brakes: Aluminium Linear-Pull V-Brakes with Jagwire LEX-SL cable housing.

• Brake Levers: Promax BL367-AL, Reach-Adjustable Aluminium Levers.

• Crankset: Forged Aluminium Low Q-Factor, 36T Chainring, 140mm Crank Arm Length.

• Cassette: Shimano CS-HG400, 11-45T, 8-Speed.

• Bottom Bracket: Thun Sealed Bearings, CrMo 119mm Axle.

• Chain: KMC 8-Speed.

Wheels & Tires

• Rims: Aluminium Double-Wall, Machined Sidewall with Wear Indicators, 32H.

• Hubs: Aluminium Front (M6 Bolted) / Shimano FH-N300 Freehub Rear (Nutted Axle).

• Tires: Nutrak by Vee Speedster, 27.5 x 1.95", Puncture-Resistant Belt, Reflective Sidewalls.

• Pedals: Compact Nylon Resin Platform with Ball Bearings.

• Approx. Weight: 10.7 kg / 23.58 lbs.

Key Highlights

• Ultra-Lightweight 10.7 kg Build: By utilizing an aluminium frame and rigid aluminium fork instead of heavy steel components or cheap coil suspension, the Dimension 27.5 drops significant mass compared to standard youth bikes, making handling effortless.

• Shimano Essa 1x8 Wide-Range Gearing: The 36T single chainring up front is paired with a wide 11-45T 8-speed cassette. This massive gear range removes front derailleur complexity while providing a low crawler gear for climbing steep hills.

• Youth-Proportioned Contact Points: Features scaled-down 19mm diameter handlebar grips to give smaller hands a secure hold, short 140mm crank arms to keep pedaling hips aligned, and reach-adjustable Promax brake levers.

• Nutrak Speedster Multi-Surface Rubber: High-volume 1.95" Speedster tires roll fast on asphalt while offering micro-tread grip on hardpack dirt and canal paths. Integrated flat-resistant belts prevent punctures, and reflective sidewalls boost low-light safety.

• Bridge to Adult Bikes: Sized for cyclists aged 11+ (144cm to 162cm tall), the bike utilizes full-size 27.5-inch wheels to deliver higher rollover efficiency, maintaining speed over bumps while getting growing riders accustomed to adult wheel standards.