Brother Cycles Kepler frameset

The Kepler has been a staple of the Brother Cycles range for over ten years and has been continuously developed to become the stylish and versatile steel frame it is today. The popular Kepler geometry remains unchanged, but functional and visual updates bring the model up to date with modern, durable all-road and bikepacking frames.

Size: 50,52,54,56,58,60

Colour:green metallic

blue metalic

Technical specifications

Frame material:

• 4130 chromoly steel
• Double butted main triangle
• ED-coated

Brake mount:

• Flat mount
• Max. Rotor size: 160 mm

Rear triangle:

• 12×142 mm thru axle (included)

Seatpost:

• 27.2 mm

Headset:

• 1 1/8" Ahead (not included)

Front derailleur clamp:

• 28.6 mm

Chainring compatibility:

• 52-39-30 (Triple)
• 50-34 (Compact)
• 48T (Single)

Bottom bracket:

• 68 mm BSA / ISO thread

Tyre clearance:

• up to 700×45c
• up to 650b×48c

Fork:

• 4130 chromoly, brazed
• 300 mm steerer tube
• 12×100 mm thru axle (included)

Weight:

• Frame (56 cm): 2.25 kg
• Fork (uncut): 1.2 kg

Certification:

• ISO 4210 tested

Recent updates:

• Brazed steel fork with dynamo cable routing and triple mounts
• Internal cable routing for the rear brake
• Brazed-on seat clamp
• Three positions for bottle cage
• Metal head tube badge "Oak Leaf"
• Revised hand-drawn branding for 2026

The Kepler can be ridden with both 700c and 650b wheels and offers tyre clearance up to 700×45c and 650b×48c respectively - ideal for demanding surfaces. The frame is made of double-butted 4130 chromoly steel, which perfectly combines comfort, stability and durability. An ED coating under the paint provides additional protection against corrosion.

The frame is fully equipped for adventure: compatible with front and rear pannier racks, mudguards, three bottle cages and triple cage mounts on both fork blades - perfect for bikepacking.

Since its launch, the Kepler has been ridden all over the world - from the Australian outback to the hills of California and the Highlands of Scotland. Whether it's a multi-day bikepacking race or a daily commute, the Kepler will get you to your destination reliably and in style.