DESCRIPTION
The Thunder Frameset is made for riders who want more versatility, whether that means city streets, mixed pavement, or light gravel. With a TIG-welded, double-butted Reynolds 725 steel frame, clearance for wider tires, and mounts for fenders and racks, it gives you a solid foundation for a build that can take you far beyond smooth pavement.
Lightweight Steel Construction. The Thunder uses heat-treated, double-butted Reynolds 725 chromoly for a frame that feels both stable and lively. Oversized main tubes and slim stays help keep weight down while giving the bike the strength and responsiveness needed for a range of terrain.
Artisan Craft and Finish. Every frame is hand-built by skilled artisans with roots in Japanese frame-building traditions. You can see it in the alignment, the smooth welds, and the overall finish. The frame receives a traditional wet-paint application followed by a clear coat, giving each color a deep, polished look.
Versatility by Design. With room for wider tires and full rack and fender mounts, the Thunder is designed to expand your riding options. The frame and fork include eyelets and bosses for utility and adventure setups. Removable cantilever brake posts give you flexibility in brake choice, allowing options ranging from cantilevers to mini V-brakes or V-brakes, depending on your needs.
Crafted for Real Use. The Thunder features investment-cast dropouts, chromoly fork blades, and carefully finished TIG welds throughout. It is designed to hold up to everyday riding while maintaining a smooth, responsive feel that encourages longer and more varied routes.
TECH SPECS AND NOTES
- Includes: Frame, fork, complete headset, seat post clamp, and bottle bolts.
- Weight (55cm): 6.7 lbs
- Accepts 68mm English threaded bottom brackets.
- Threadless 1-1/8" steel steerer tube. Note: The steerer tube length is precut to match your frame size to allow 35-40mm of spacers between headset and stem.
- Wabi Pro headset included along with spacers, top cap and installed star nut.
- 100m front dropout spacing; 120mm rear dropout spacing
- 27.2mm seatpost compatible.
- Front and rear removable cantilever posts.
- Tire clearance up to 45mm (though some customers have made 50mm work).
- Accommodates certain track/messenger cranksets (tested to ~142mm Q factor). Note: Drive-side chainstay has a dimple to ensure crankarm spider and chainring clearance.
- Eyelets/bosses: Two rear dropout eyelets, two front fork eyelets, fork blade mount bosses for racks (bolts included) and seat stay mount bosses (bolts included)
- Integrated cable stops on top tube. We recommend cable clips for a rear brake install.
- Bottom bracket is not included.
Note: Rear brake bridge is part of the frame for cantilever brakes. Front brake hanger must be purchased separately for front cantilever brakes.
SIZING
We highly recommend reviewing our sizing page before purchasing. Look at both your height and your actual inseam / standover height. The guide below can also provide some general guidelines.
| RIDER HEIGHT | FRAME SIZE | STANDOVER HEIGHT |
| 5'4 - 5'7 | 49CM | 30.2IN |
| 5'7 - 5'10 | 52CM | 31.3IN |
| 5'10 - 6'1 | 55CM | 32.5IN |
| 6'1 - 6'3 | 58CM | 33.6IN |
| 6'3 - 6'6 | 60CM | 34.8IN |
Frame size is measured center-to-center of the seat tube. See more on our sizing page.
COMPONENT SIZING
The Classic is designed around a 170mm crankarm, a 24mm setback seatpost, and stem lengths that change with frame size and rider height. You can find our recommendations under 'Determining Bike Components Fit on the sizing page. Using different parts may change the fit.
IMPORTANT NOTE ON COMPATIBILITY
We can only guarantee compatibility with the parts used on our complete bikes. If you’re planning a custom build, feel free to reach out—we’re happy to share anything we know—but we can’t offer refunds for issues with third-party components.