Widening the bits

Having no brakes is not that safe.  I think I may get some.

Well, truth be told, the scooter does have brakes, they are just very, very (very) poor.  When I purchased the original kick scooter and (attempted) to kick it home from work on the day it was delivered, the brakes had no stopping power even then.  Now it is 25kg heavier and 25km/h faster.

So I ordered an e-bike disk brake from the manufacturers of the motor in China.  Only took a week to arrive, which is great!  I now have a shiny new disk brake set-up with nice grippy cable-driven callipers.  And they don’t fit.

The problem is two-fold.

  1. There is no mount for the disk/rotor on the motor
  2. There is no room between the rear forks for the brake installation

The following part of the post is mostly for the benefit of Father, who is a former fitter and turner (engineer).  He’s going to make sure my plans to widen the rear forks are solid, and then hopefully do it for me 🙂  Go Dad!

This is the current rear of the frame.  The forks need to be widened slightly (perhaps 60mm) and lengthened (although, not strictly necessary, so even 50mm will do).

This is the current rear frame

These are the measurements of the rear assembly:

Rear assembly with measurements

And here is my plan to widen and lengthen the forks:

  • Hacksaw off part of the existing tube, including the axle mounts.
  • Take some tube the same diameter as the current frame (28.7mm) and weld it along the outside of the current tubes.
  • Make some new axle mounts (or carefully re-purpose the old ones) and weld them to the new tubes
  • This will give an extra 50mm of length, and extra 57.4mm of width, and removing the end of the existing tube will give extra room for the brake assembly.

Plan for the modified rear end

What do you think dad?  No bending required, and hopefully not that much fabrication.  But will it have the requisite strength?

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