Almost as wierd is my "woodie" fixed-gear mountain bike; this is 1930's Hercules with a reversable hub. One side has an 18 tooth fixed cog, the other has a two-speed freewheel, 20 & 30 teeth. This bike has a Shimano 105 crankset, 42/52. The 52/18 gives me a fixed gear with a gain of 5.56 (75" / 6.00 m) , which I use most of the time. On the freewheel side, I have a choice between the 52/20 --5.01 (68" / 5.44) road gear and the 42/30 --2.70 (36" / 2.91 m) off-road gear. This bike has 559 mm mountain-bike wheels, usually with 1.5 semi-slicks, though sometimes I put on a front wheel with a knobby if I plan to go off-road. I've got a separate page about this bike
Most of the above bikes have 165 mm cranks for improved cornering clearance.
Then there is my beater, an early '50's Rudge, 531 main tubes. Originally equipped with a four speed Sturmey-Archer hub, this all-steel bike has mostly original equipment, except I replaced the rear hub with a vintage 40 hole steel fixed hub.
This is a rustbucket that lives outdoors behind my house, I never lock it. With a milk crate on the Pletscher rack, it is used for short-hop errands. This bike is deliberately uncomfortable and hard to ride, to deter thieves. It is a 21" frame, a couple inches too small for me, with a huge seatpost and the plastic base of a cheap ten-speed saddle with the cover and foam torn off.
The North Road handlebars are low and have been flipped upside down, so they are at least a foot lower than the saddle. Sharp steel rattrap pedals with no clips nor straps complete the instrument of torture. Anyone rash enough to try to ride this bike would have to have very long legs like me, and even then, a rider who was not accustomed to fixed gear riding would surely crash painfully if he or she tried to ride off on my Rudge. It has a gain ratio of 5.01 (68" / 5.44), and is comfortable enough for me for rides of a mile or two.