Bikeliner Design Notes 2017-05

This is the state of design for the Astro Bikeliner from May 2017. This sentence will be replaced with a link to newer information when available.


The not-so-accurate-and-rough mock up of an Astro Bikeliner

Possibilities for bike placement

The Ultimate Dream™ (not pictured)

Driver is in the hood area and the back has 11 or 12 riders.

The Dream™

10 or 11 riders. Driver moved forward and upright.

Driver uses stock seat and placement

This one is not ideal, but keeps the driver area intact from the stock van for easier implementation.

Bare minimum for the short term

One row of five bikes. This would be the minimum configuration for Tour de Fat if needed, and not a long term plan in any way. Should work with the dash intact and the driver sitting in the stock driving position.

Design mentality

Leverage existing cheap used components to create a fun “pub bike” with minimal fabrication. Bonus points for silliness.


  • Stationary bikes now move… …sideways.
  • 3 Speed internal shifting gears (if used) have planetary gears. Who doesn’t want an Astro with planetary gears?
  • It’s a former automobile powered by about 10 people. C’mon!

Existing parts

  • Astro Van (QTY 1) : Has sufficient space between the rear wheel wells for two exercise bikes facing each other, a flat floor, rear wheel drive, and they made a lot of them that can be had for cheap in 2017.
  • Exercise Bikes (about 10) : Can be had for $10 on a good day with a good saddle. These are built to stand on a flat floor, so fabrication needs are greatly reduced.


Drivetrain is divided into three compartments:

  • Above Floor : This is the realm of exercise bikes and the people that ride them.
  • The Cloud : This is drive system that goes under the floor, taking the Power Take-Off (PTO) chain from the exercise bikes and connecting them to the Astro’s differential. Despite being below the floor, it’s called The Cloud.
  • Astro Van : The rear differential and wheels. The tires are 215/75R15 (27.7 inch diameter) and the rear end is a 3.73.

Above Floor

Exercise Bikes

Exercise bikes are non-standardized due to costs, time, and availability. A variety of frame designs, manufacturers, dimensions, and weights. They are all with the front dropout (formerly holding a wheel, weighted disc, or a fan).

The current thoughts:

  • Many (or all) exercise bikes will use their original chainring, crank, and chain to the hub in the dropout.
  • The front wheel/disc/fan will be replaced with a non-wheel hub with an added PTO gear to drive a chain to ”’The Cloud”’

Power-Take Off (PTO) Hub

The PTO hub has a freewheel mechanism for the chain coming off the chainring from the exercise bike. The hub also has a gear added on, way or another.

The current thoughts on possible PTO hubs:

3 speed hub (circa 1980)

  • They made a lot of these, they can be had cheap, and I can probably find 10 on them in a reasonable period of time. (good)
  • They want a shifter (added complexity + part count = bad)
  • They don’t have PTO gears. Have to add the PTO gear. (normal)
  • Possible 3 speed configurations:
    • 3 speed + added gear. A gear is welded on or otherwise to the center of the hub.
    • 3 speed + welded chainring bracket. A bracket is welded that allows a chainring to be attached to it. The PTO gear in this configuration can be changed/replaced.
    • 3 speed + mechanically fastened chainring bracket. By some miracle of awesomeness (as miracles tend to be) there’s a way to screw mount the chainring bracket to the 3 speed hub.

Single speed

Way more availability + options.
Possible single speed configurations:

  • Use of a commercially produced “flip flop” hub. They’re actually making lots of these more recently and on Walmart bikes sometimes no less, but there hasn’t been decades of common production as is the case with the three speeds.
    • You’re stuck with the (tiny) gear (bad?)
    • Built and done (good!)
    • Higher cost since there would be new parts utilized.
  • Add a single gear mechanically or by weld.
  • Add a 7ish gear rear cassette to the hub somehow (added gear options built in + possibility for derailleur shifting to The Cloud)

The Cloud

The Cloud is below the floor and takes the drive from the chains leaving the exercise bikes and turns a driveshaft connected to the Astro Van’s rear differential.

Astro Van

The Astro Van is the frame, floor, steering, and braking platform for the project, or in other words, the Astro Van is the platform.

  • The four 215/75R15 tires are 27.7 inches in diameter and are in nice shape.
  • Rear differential is a 3.73.

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