Shaft Drive Klunker bike

[BartRidesEternal]

Hey Ratters,

I'm working towards my first completely scratch built bike.
And I thought; Lets share the whole process!

At the moment I am working on setting up and arranging my workshop, since I'm slowly working towards building frames for customers.

Regarding this bike I had in mind: I have five brand new shaft drives in boxes. Three 'singlespeeds' or 'three speeds' and two with an threaded rear sprocket.

Two types: Right is for regular hubs like the Shimano CB-E110 or Nexus 3.

At the moment I am doing lots of inquiry! Measuring, calculating and looking for good mountainbiking geometries.

The shaft drives 'chainstay length' is fixed, so that is why I can't build a long chainstay (belly mounted BB) cruiser with this.

Right now I am figuring out the measurements of this shaft and how I build a durable frame with this.

Unfortunately VERY fat tires won't fit, probably a maximum of 2 inches, depending on wheelsize.... which is dependant on the internal gear ratio....

Measuring the dropout width.

BB shell.

My sketch of the bike.
A looptail, shaft driven klunker bike

I intend to use CroMo tubing.

 

[BartRidesEternal]

Little update:

I checked the intended dropout width in multiple ways: In my alignment jig and by assembling/adjusting the rear hub.

Shimano CB-E110 hub.

I also checked the Ratio: 1:2
1x crank turn = 2x wheel turning.

Tire clearance is meh. We'll see what we can do with that.

 

[Pondo]

Pretty cool! This will be a fun project.

 

[BartRidesEternal]

Bottom bracket shell is machined. Only a section to be removed that has to be milled:

This is how the bottombracket shell looks in the BRIK bikes (a Dutch brand that sells bikes with shafts).

Youtube video link

Since the 'open section' of the bottom bracket, especially in the corners, has a higher level of stress and tension, I decided to thicken the ends and have that part a lot stiffer.
I purposely designed the open section with a radius, so that tensions do not concentrate too much in a 90 degree sharp angle.

The bottom bracket is a 51,2 inner diameter (almost the same as a US BB) and 57mm outer diameter on the thinner section. The ends are 60mm. So a central wall thickness of 2,9mm

I don't think this will be a light bike, but then you have more energy downhill

 

[ifitsfreeitsforme]

Neat. I've wanted a shaft drive bike for twenty plus years.

Are you designing with Creo?