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Building a PennyFakeThing

Parts required
Tools






Take one conventional Cycle               Starting bike

Remove bits                                          Bits removed

Front Assembly
The Geometry


Rear wheel and backbone


Frame alignment

Completed Frame
Completed frame

Now for something to sit on

The Seat


Aim to get your centre of gravity between the wheel centres .
Check your inside leg measurement.
This gives the dimension from the seat to the pedal in it's lowest position.

The foot peg can be welded on above the rear fork. High enough to easily slip onto the seat.
Seat
If you want to give the girlfriend or other half a lift then fit a peg both sides.

It was clear that if the quick release on the front wheel came loose there would be unfortunate consequences. The front wheel would abruptly stop, pitching the rider over the handlebars.
So the following solution was constructed.
keeper
Keeper2
keeper fitted

I added a couple of gussets for reinforcement to the top of the backbone and between the joins on the forks.

Finished Result
Finished PennyFakeThing

Some tips on riding.

The weight on the seat greatly reduces the risk of pitching over the front. The weight is kept between the axles. Remember also it is front wheel drive.

1.    So ALWAYS keep your weight on the saddle. Even going up hill.

2.    Getting on. Step up. SIT DOWN. Then pedal. This is very important. Leaping for the pedals will put your weight ahead of the front axle. (bad)

3.   Getting off. Stop pedalling. (These bikes due to high centre of gravity are very stable so can be ridden slowly. You don't need to rush getting off. You have plenty of time). Allow to coast, reaching back for the mounting peg. When almost stopped put your weight on the peg and brake if necessary. Step down.






Additional Notes:

The wheelbase was made short deliberately in this case as it has the advantage of improving maneuverablity, particularly at low speeds (it makes turning circle smaller)
The bike will be safer at speed with a longer wheelbase. This can be achieved by moving the rear wheel further away from the front.
Avoid the temptation to rake the forks forward. While this may appear to improve matters, it causes two serious problems.
  1. It greatly increases the cantilever bending moment applied by the backbone to the headset. This can result in the backbone bending or breaking at this point.
  2. It greatly increases the trail (castor effect) of the steering making it heavy and prone to 'Tramlining' (follows the undulations in the road. Have a look at safety cycles with a steep head angle. They have the forks bent forward to reduce the trail. Safeties can get away with this as they have a triangulated frame which can withstand the extra stresses on the headset. Penny Farthings can't. (see point one above)
One can achieve greater flexibility in design by starting with a smaller wheel than the one used. For example a 24" or 20".