Brother Cycles Kepler Steel Frameset
Brother Cycles Kepler Steel Frameset
- 4.9 from 782 Google reviews
- Independent Bike Dealer of the Year 2025, BikeBiz Awards
- UK delivery from £4.99, or free collection from our Bow shop at E3 3XS.
- Checked by our team before it leaves us
Collecting instead? Email us or message us on WhatsApp before you visit, so we can have it ready for you.
The steel all-rounder that has carried riders from the daily commute to multi-day bikepacking races for over ten years.
The Kepler is the frame Brother Cycles built their name on. The geometry has stayed the same because it works: stable when loaded, relaxed enough for long days, and quick enough to enjoy on the way to work. The latest version adds a lugged steel fork with dynamo routing, internal routing for the rear brake, a brazed seat collar and a metal Oak Leaf head badge.
It runs 700c or 650b wheels, with room for 700 x 45c or 650b x 48 tyres, and has every mount you need for racks, mudguards and three bottles. Double butted 4130 chromoly with an ED coating under the paint keeps it riding sweetly and protects it from the inside out.
Why we chose this for our customers:
- One frame, many bikes: build it as a commuter, a tourer, a gravel bike or a bikepacking rig
- Two wheel sizes: 700c up to 45c, or 650b up to 48mm for more grip and comfort
- Loaded and ready: front and rear rack mounts, mudguard eyelets, three bottle positions and triple cage mounts on each fork leg
- Made to last: 4130 chromoly steel, ED coated against corrosion, tested to ISO 4210
- Threaded and standard: 68mm threaded bottom bracket and 1 1/8 inch steerer, so it is easy to service for years
Specification
- Frame: 4130 chromoly, double butted main triangle, ED coated
- Fork: 4130 chromoly lugged fork, 300mm steerer, 12x100mm thru axle included, dynamo routing
- Rear: 12x142mm thru axle included
- Brakes: flat mount disc, 160mm max rotor
- Tyre clearance: 700 x 45c or 650b x 48mm
- Seatpost: 27.2mm
- Headset: 1 1/8 inch threadless (not included)
- Bottom bracket: 68mm ISO threaded
- Front derailleur clamp: 28.6mm
- Chainrings: up to 52-39-30t triple, 50-34t double, 48t single
- Weight: 2.25kg frame (56cm), 1.2kg fork uncut
- Tested to ISO 4210, three year frame guarantee from Brother Cycles
Geometry
| Size | 50cm | 52cm | 54cm | 56cm | 58cm | 60cm |
|---|---|---|---|---|---|---|
| Seat tube (C-C) | 485 | 505 | 525 | 545 | 565 | 585 |
| Top tube | 520 | 530 | 545 | 560 | 575 | 595 |
| Head tube | 95 | 95 | 105 | 124 | 142 | 161 |
| Head angle | 71 | 71 | 71.5 | 72 | 72 | 72 |
| Seat angle | 74.5 | 74 | 73.5 | 73 | 72.5 | 72 |
| Chainstay | 430 | 430 | 430 | 435 | 435 | 435 |
| Stack | 530 | 530 | 543 | 562 | 580 | 598 |
| Reach | 372 | 378 | 384 | 387 | 392 | 401 |
| Wheelbase | 1009 | 1014 | 1014 | 1025 | 1035 | 1049 |
All measurements in mm and degrees.
Ideal for: riders who want one steel bike for commuting in the week and touring or bikepacking at the weekend.
Brother design their frames in London and we build them up on the bench in Bow, a few miles across East London. Bring us a parts list, a pile of components you already own, or just an idea, and we will spec, build and fit it for you. See the full Brother Cycles range, our other framesets, or book a build through our workshop.