Extention BB24 Trial Crank

Product code: 14190

External BB trial crank to fit a variety of frames and drive set-ups!
Supplied with sealed bearing, external BB.
Recommended for use with a fixed sprocket.

- New from Extention, the BB24 Trial Crank!
- As fitted to the Extention Rise 20 complete bike.
- Made from forged 7075 T6 aluminium for a balance of strength and light weight.
- Wide crank arm profile increases stiffness and rigidity with material removed from the rear of the crank arms to keep weight low.
- Steel 24mm spindle bonded into the drive side crank arm and features increased wall thickness at the bearing surfaces.
- 40 spline left-hand crank interface, similar to the Hollowtech Shimano design, uses a two bolt clamp and alloy preload bolt for secure fitting and easy BB preload adjustment.
- Standard 1.37" x 24tpi thread fits a wide range of fixed sprockets and freewheels.*
- Supplied with Extention, sealed bearing, external BB to fit 68 and 73mm frames. The crank is supplied with a selection of axle spacers to achieve the best fit for your frame and drive set up!**
- Supplied as a kit including crank arms, crank preload bolt, BB and crank spindle spacers.
- Crank spacing of 156mm, measured from the inside edge of the pedal thread to the opposite crank.
- Supplied in 165mm length only.
- Not recommended for street trial use.
- Weight: 727.20g (Complete kit including BB and all crank axle spacers).

* We recommend using this crank with a fixed sprocket, which gives more adjustment for chain line and frame / BB clearance. It can be used with a freewheel, (Extention's frames are designed for use with this crank, so there is more clearance for this) but it may require some experimentation with the crank axle spacers supplied to achieve adequate clearance of the freewheel from the RH BB cup. The crank axle MUST be inserted into the left-hand crank arm, so both pinch bolts overlap the splined end of the spindle. Not doing this may result in crank failure, which will not be covered under warranty. The preload bolt should be tightened to around 1Nm Max and the crank pinch bolts to 14Nm max.

** Axle spacers supplied will be required for 68 or 73mm BB shell equipped frames. The crank is spaced using these axle spacers to fit frames rather than spacers on the BB. As above, some experimentation may be needed to achieve a good fit, failure as a result of poor fitting will not be covered under warranty. If you need any advice, just get in touch!

Ensure that your pedals are tightened to at least 310 in-lbs (35 Nm) every 5 minutes for the first few rides. Before fitting, it's also a good idea to make sure your pedal axles are clean (a wire brush works well) then greased before installation.
Similarly, always check crank pinch bolt torque is at least 124 in-lbs (14Nm) every 5 minutes for the first few rides, then each and every ride after that.
Failure to keep your pedals or crank bolts tight as described above is likely damage your cranks and this will not be covered under warranty.