Bolt Lenghts / Specifications
Always Consult Factory Manuals Bicycle brake systems are critical safety components. Before selecting or installing any mounting hardware, you must always refer to the specific factory service manuals provided by both the brake manufacturer (e.g., Shimano, SRAM, Magura) and your bicycle’s frame or fork manufacturer. Specifications for bolt lengths, spacing adapters, and mounting interfaces vary significantly between brands, models, and frame designs.
The Danger of Incorrect Bolt Length Using the wrong length bolt can result in a catastrophic loss of braking control, leading to severe injury or death.
- Bolts that are too short: Will not achieve adequate thread engagement. Under the intense force of hard braking, insufficient threads can strip out of your frame, fork, or adapter entirely, causing the brake caliper to detach while riding. (As a general rule, a minimum thread engagement equal to the bolt diameter—typically 5mm to 6mm—is required, but you must verify the exact minimum required by your specific components).
- Bolts that are too long: Will bottom out inside the mounting hole before the caliper is completely clamped down. This leaves the caliper loose, allowing it to move or jam into the brake rotor/wheel rim. Furthermore, on carbon fiber frames or forks, over-length bolts can break through the internal walls of the mounting boss, permanently destroying the frame or fork structure.
Torque and Fastener Security
- Never Guess Torque Values: Always use a calibrated torque wrench to tighten caliper mounting bolts to the exact Newton-meter (Nm) specification listed in your component manuals. Under-torquing can allow the caliper to shift under load, while over-torquing can crush carbon mounting tabs or strip metal threads.
- Thread-Locking Compound: Brake hardware is subjected to severe, repetitive vibrations. Never install caliper bolts without an appropriate medium-strength thread-locking compound (such as blue Loctite) or the manufacturer-specified locking washers. Check bolts regularly to ensure they have not backed out.
Professional Installation Recommended Proper brake setup requires precise alignment, specific tools, and mechanical expertise. If you are unsure about bolt length calculation, spacer configurations (such as CPS washers or flat-mount spacers), or thread compatibility, do not attempt to install these parts yourself. Take your bicycle and components to a certified professional bicycle mechanic for proper installation and inspection.
Rear Brake Bolt Lengths
| Front | Rear | |
| Flaanimal 3.0 follows 5.0 | 13-15mm | 22mm ^^ |
| Flaanimal 4.X follows 5.0 | 13-15mm | 22mm ^^ |
| Flaanimal 5.0 SRAM | 15mm * | 22mm ^^ |
| Flaanimal 5.0 Shimano | 13mm ** | 22mm ^^ |
| Flaanimal 5.0 Ti SRAM | 15mm * | 22mm ^^ |
| Flaanimal 5.0 Ti Shimano | 13mm ** | 22mm ^^ |
| Flaanimal 6.0 SRAM | 15mm * | 27mm * |
| Flaanimal 6.0 Shimano | 13mm ** | 27mm * |
| Traildonkey 4.0 SRAM | 15mm * | 22mm ^ |
| Traildonkey 4.0 Shimano | 13mm ** | 22mm ^ |
| Traildonkey 4.2 SRAM | 15mm * | 27mm * |
| Traildonkey 4.2 Shimano | 13mm ** | 27mm * |
| * – Use SRAM washer (1mm) | ||
| ** – Shimano Bolts incl washer | ||
| ^ – No washer needed | ||
| ^^ – Use 2x SRAM washer | ||
| Front brake caliper bolts | Supplied with calipers. Typically 13-15mm |
Spork 1.2 bolts:
Crown hole is not threaded, use a through bolt as follows.
- Crown Bolt Thread Size: M5
- Crown Bolt Female End Length: 45mm (ideally fully threaded)
- Crown Bolt Male End Length: At least 35mm (ideally fully threaded)
- Crown Accessory Mounting: You can use a longer male end for thicker items (like dynamo lights or racks), but you may need to add washers depending on the thickness of the mount.
Mid Leg eyelets use M5 x 15mm bolts.
Use nylon washers between bolt and cage / rack and also between the cage / rack and fork to prevent marring your paint finish.
Fork-end eyelets use M5 x 10-13mm bolts.
Grease bolts well, torque to 5 nm.
Spork 2.x to 3.x bolts:
For the Rodeo Spork 3.0, the specific crown bolt length depends on what you are mounting:
- For fenders: Use an M6 x 60mm bolt, plus the threaded thickness of your nut.
- For a dynamo light or rack: Use a longer M6 bolt (usually 60mm to 70mm, depending on the thickness of the mount).
Important Installation Guidelines:
- Washer usage: Always use nylon washers between metal bolts/nuts/mounts and the carbon fork crown to prevent scarring and structural damage to the carbon.
- Torque limit: Do not exceed a maximum of 5 nm of torque when mounting to the fork crown.
- Hardware: The fork cannot accommodate recessed brake nuts, so you must use a standard nut and bolt setup.
Mid Leg eyelets use M5 x 20 mm bolts.
Use nylon washers between bolt and cage / rack and also between the cage / rack and fork to prevent marring your paint finish.
Fork-end eyelets use M5 x 10-13mm bolts.
Grease bolts well, torque to 5 nm.
Spork 4 bolts
For the Rodeo Spork 4.0, the specific crown bolt length depends on what you are mounting:
- For fenders: Use an M6 x 70mm bolt, plus the threaded thickness of your nut.
- For a dynamo light or rack: Use a longer M6 bolt (usually 70mm to 80mm, depending on the thickness of the mount).
Important Installation Guidelines:
- Washer usage: Always use nylon washers between metal bolts/nuts/mounts and the carbon fork crown to prevent scarring and structural damage to the carbon.
- Torque limit: Do not exceed a maximum of 5 nm of torque when mounting to the fork crown.
- Hardware: The fork cannot accommodate recessed brake nuts, so you must use a standard nut and bolt setup.
Mid Leg eyelets use M5 x 15 mm bolts.
Use nylon washers between bolt and cage / rack and also between the cage / rack and fork to prevent marring your paint finish.