The different types of road bike crank axles,

Road bike cranks have shorter axles than MTB cranks. This is why road bike cranks cannot be fitted to MTBs. An exception to this are the DUB Road Wide cranks. These are also compatible with MTB frames featuring 135/142 rear dropouts.

The BB30 cranks are available in two short-spindle versions. These are only compatible with BB30 bottom bracket shells with a width of 68 mm. The BB30 long-spindle and BB386 cranks have the longer 30 mm axle and can be fitted into almost all bottom bracket shells.

For the other axle systems, there are virtually no compatibility restrictions. Although Shimano offers only a few bottom brackets compatible with the Hollowtech II system, there are many suitable alternatives from other manufacturers, such as Wheels MFG.

• Shimano Road Hollowtech II, axle diameter 24 mm, axle length 110 mm
• Sram Road GXP, axle diameter 24/22 mm, axle length 106 mm
• BB30 Road Short Spindle, axle diameter 30 mm, axle length 95 mm, with 110 mm spacer
• BB30 Road Long Spindle, axle diameter 30 mm, axle length 110 mm with 115 mm spacer
• BB386 EVO Road, axle diameter 30 mm, axle length 105 mm
• Sram DUB Road axle diameter 28.99 mm, axle length 107.5 mm
• Sram DUB Road Wide, axle diameter 28.99 mm, axle length 105 mm, with adjustment ring 108 mm