Monthly Archives: May 2020

Rear Wheel Repair on a Chain-less Bike

The iconic bicycle chain is but one variant of the many ways of propelling your steed. Having experienced quite a few of these alternatives, Re-Cycle Engineering (RCE) we weren’t surprised (nor perturbed) when asked to carry out a repair this bike:

A modern chain-less bicycle.

Note (1) the electric motor operating the front wheel. Present British law only allows for pedal-assist bikes (i.e. you must be pedaling for the electric motor to be operational). Note (2) the lack of a chain. So, how does it work?

Let’s have a look at the chain-set:

A chain-set without a chairing or chain – what gives?.

Back story: RCE helped out the owner a few weeks earlier. The cyclist had accidentally damaged the right-hand pedal crank and needed it to be replaced. For those of you unknowledged, a right pedal has a right-handed thread on it (clockwise to tighten) and the left on has a left-handed thread on it (anti-clockwise to tighten). Of course we could have sold him a expensive crank arm for a right pedal which would have delayed his return to cycling. Alternatively we could have fitted a left-hand crank with a left pedal (not ideal – meaning that he would be permanently having to buy 2 sets of pedals at a time). To get the cyclist back on his saddle the same day, we agreed upon fitting a spare, pre-used right-hand crank (quick and cheap).

Still, we haven’t answered the question of how the bike is propelled? Let’s take a gander at the rear of the bike:

No chain and no cogs.

Looks a bit weird. Let’s take of the hub’s gear-changing ‘click-box’ and the cover off where the chain should be:

Does this explain anything?

Now we see a strange-looking gear on the wheel’s hub. Let’s take off the rear wheel and look at what that gear interacts with:

Any the wiser?

Maybe these to pictures will help:

A) straight-cut bevel gears (often seen on canal lock).
B) Spiral-cut bevel gears (often seen in tricycles and cars differentials).

The wonderful 1898 book, “The Modern Bicycle and Its Accessories by Alex Schwalbach and Julius Wilcox” devotes the second chapter to shaft-driven bevel-geared bikes (and other alternatives).

Back to the repairing the rear wheel:

A closer look at the gear on the right-hand side.
Shimano’s Roller Brake on the left-hand side.
Flip side of the Roller Brake.
Oh dear!
14 (out of 36) spokes damaged.
At least the remaining 22 spokes were OK.
Spokes replaced and tensioned.
Rear wheel, brake, bevel cover and click-box installed and set.
Ready to go
(after the saddle & seat-post are installed.


Brought a tear to our eyes: ‘Sea You’, A Touching Animated Short That Tells the Story of Profound Loss Told In Reverse Order.

Best Friends and puddles.

A scandal that stains the history of the grand old city of Leeds.

Cycling is bad for the economy…

A journey through the fragmented unconscious of our modern times:

Click pic to view (or HERE if removed).

… and, to finish with, bit of young blues:

See you all soon and be well.