Via Ride the Machine.

There are at least four different approaches to getting the power from 2 pairs of legs to the rear wheels.

The crossover front (seems to have been popular with French constructeurs):

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The crossover rear (most common):

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And then the 2 reasons for this post…

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The single side rear (a single side front would be crazy – which means it’s been done somewhere). I found the Paketa V2r by googling racing tandem bicycle; after seeing the bike that ends this post, I was curious about what the current road racing state of the art might look like. I’m not surprised that the timing chain (the link between the captain and the stoker) isn’t a chain at all – belts are popping up in applications where the chainline doesn’t vary – singlespeeds and hub-geared bikes, especially. The biggest advantage that single side rigs have over crossovers has to do with cranksets. On a normal crankset, the left pedal/crankarm is reverse threaded. If it were threaded normally, rotational forces would tend to loosen things up. Since 3 of the crankarms on a crossover drive are on the ‘wrong’ side (both in front and the left on the rear on a crossover rear, for example), you need to purchase special tandem cranksets to get the threading right. On a single-side, the cranks are set up just as they’d be on a solo bike; thus, one can use a super light state-of-the-racing-art set of cranks. You give up the ability to use a triple chainwheel setup, but if racing is the goal, one presumably doesn’t need a super low gear. The folks who make the bike shown below make some other claims about their single side setup regarding torque and bearing stress that I have some trouble getting my head around. It seems to me that the stresses would just switch sides, not somehow balance out. That aside – still a pretty dang cool bicycle.

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Finally, the bike that started me thinking about drivetrains in the first place. This tweet led to this photograph:

Which led to me learning about daVinci Design’s drivetrain. I’ll quote their website (I like the sound of jackshaft rather than intermediate shaft – feel free to substitute as you read):

The main component of da Vinci Designs’ ICS is an intermediate drive shaft six inches in front of the rear bottom bracket. The intermediate shaft has two single-speed freewheels on the left side that are independently driven by the cranks at twice the rotating speed and half the torque. On the right side of the shaft, four Hyperglide™ cogs drive the bike. The chain rings are half the size as those on a conventional tandem because of the double rotation of the intermediate shaft. The combination of 12-, 18-, 24-, 30-tooth driving gears equals 24-, 36-, 48-, 60-tooth chain rings. *

Wicked smart! Were I to spring for a tandem (good tandems are NOT cheap), this would be #1 on the list with a bullet. I wonder whether you could get away with eliminating the freewheel body on the rear wheel? After all, the captain and stoker are already decoupled by virtue of the freewheels on the jackshaft and keeping the ‘final drive’ rotating all the time would mean that the captain could shift even when no one’s pedalling. Da Vinci – call me. I’ll sign the idea over in return for just one of your gorgeous machines.

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To finish up, some supplementary material in the form of YouTube videos. First, you didn’t think I’d talk about tandems without embedding this, did you?

Some Paralympic Tandem Pursuit action (the stoker is blind or visually impaired). In pursuit races, opponents start of opposite sides of the velodrome and whichever team closes on the other, wins. In this race, there’s a full-fledged catch (5:35).

No tandems in this one, but it does serve to emphasize the importance of aerodynamics and, dang, team pursuit is just about the most graceful thing in sports.

Wheeeeee!

It’s like deja vu all over again – I did it last summer with a picture of a porteur near the Moulin Rouge; this year the spoke cards are Prisoner-themed.

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Folks who ride bikes to NHMM meet-ups will receive a spoke card (while supplies last, but I have 36 of ‘em). Be seeing you!

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A shoutout to the good folks at Infinite Imaging who did a bang-up job on printing and lamination.

Crucially, steel can be repaired anywhere in the world by a man with a blowtorch and a welding rod. I know this, because I bent a steel bike in northern India, when I was riding around the world. I was slipstreaming a tractor on the Grand Trunk Road near Amritsar.We were going downhill a lick when I road into a pothole the size of a hot tub. There was no time to react. I had what American mountain bikers call a ‘yard sale’. The bike, panniers, sunglasses, water bottles, tent, pump, map and I were strewn across the tarmac. [...] It took me an afternoon to find the best mechanic, or ‘top foreman’ as the locals called him, in Amritsar. Expertly, he removed the handlebars, the stem, the forks and the stressed headset from the head tube, while attendants handed him tools as a nurse attends a surgeon. Then he shoved a metal spike through the head tube and literally bashed the tubes straight again. It was terrifying to watch.

The frame requires a bit more attention on the remaining 7,500 miles, but gets him home. And:

In the alchemy of designing aircraft tubing, Reynolds stumbled on a manganese-molybdenum alloy that made wonderful bikes. In 1935, the company introduced ’531′ tubing. It was considered revolutionary. Even now, British [and American] cyclists of a certain age go misty eyed and look towards the horizon just at the mention of ’531′.

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You get a taste in the quotes above both of the range of Mr. Penn’s inquiry and of his writing style. I found the book to be thoroughly enjoyable; style and subject both get an A. It’s a quick read – 198 pages of clear prose – and if you like bikes, highly recommended.

Two additional notes: 1) In spite of my pissing and moaning about the volume of bike lit, I recently bought a fantastic book of visual bike history (aka bike prØn). The Golden Age of Handbuilt Bicycles is a survey of mostly-French mostly-randonneur bicycles from 1909 – 2003. Inspirational – especially as regards a: 2) Current project – I’m assembling a dream bike as well. I’ll post more in a month or so; I’ve built what I’m calling a voyageur bike on a touring frame – pictures/specifications/rationales to follow once the new ride is fully dialed in.

Partially cross-posted to LibraryThing.

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Manual pages can be found here, here and here.

The Audible Audubon are a series of cards – one per species. On one side there is a picture of the bird; on the other, a brief narrative description and a clear record.

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Put the card in the microphonograph and out come calls!

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A nice little bit of late-70′s tech and a reminder of how much more available info is now that it’s digitally encoded in semi-standardized ways (see Sibley and Audubon iOS apps).

I recently won a Parrot AR drone at a benefit auction. I’ve been wishing for one since discovering them on a gagdet blog last summer? fall? and the auction was too good a chance to miss. The drone is a quadcopter with 2 video cameras (forward-facing and down-facing) that feeds video to and is controlled by an iPod/iPhone/etc. There are good videos on the Parrot site showing how the control system works; I just wanted to mess around a bit with the 3rd party control app that allows one to record the video stream from the drone. Aside – why this is not part of the standard Parrot software is beyond me.

Here’s what an innocent bystander would see (the 1st minute is crap – I’m trying to set off a flash on the cell phone to act as a visual clap-board):

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And here’s the view from the drone:

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Finally, the theme song:

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It’s an amazing little device – I may not have a jetpack, but…

Rather than being an oversight, this probably had more to do with the fact that filming technology had been left behind by our sudden leap into the Space Age, and there simply wasn’t enought room inside the cramped Vostok 1 capsule for Yuri Gagarin to wield a primitive, bulky TV or film camera.

So in early 2010, with the new giant cupola window installed on the International Space Station, and with digital filming technology now firmly in the Space Age, I began to wonder if it might be possible to trace Gagarin’s pioneering orbit around the Earth once more – and this time to film it. *

Watch it full screen!

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More info at firstorbit.org and on the firstorbit YouTube account.

At the turn of the 1970s, the great design rivalry between Bertone and Pininfarina reached an all-time high, with both companies seemingly determined to pull out all the stops to outdo one another. Bertone had perhaps opened the hostilities with the Marzal and with the first “wedge-shaped” supercar concept, the mighty Alfa Romeo Carabo. Italdesign had joined the fray with the Bizzarrini Manta and the Alfa Romeo Iguana. Pininfarina had replied using all its Ferrari firepower with the striking P5, the 512S berlinetta and the Modulo. The latter had caused quite a stir at the Geneva Motor Show in March 1970, yet nothing, not even the outlandish Modulo, could really have prepared visitors of the 1970 Turin Motor Show just a few months later to what they were about to see on the Bertone stand. The car was officially labelled “Stratos HF.” Nuccio Bertone had initially wanted to call it “Stratolimite,” as in “limit of the stratosphere,” clearly inspired by its space-age design. But after some time, it came to be known simply by its internal nickname: Zero.

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One of the most beautiful concept cars ever produced (IMHO) – up for sale May 20. Anyone fancy a trip to Lake Como?

The Stratos Zero spawned another favorite of mine – the plain ol’ (hah!) Stratos:

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Via Hemmings.

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Not-great camera work (who am I to talk?), but interesting footage regardless – looks like there’s at least one leaning-wheel rig:

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I’m including this for the drilled cylinder action. From a thread that led me to the first YouTube video, “Since the engines were four stroke anyway, they would often drill holes in the cylinders just above the top of the piston when it was at the bottom of its stroke. This improved exhaust scavenging and gave a higher top speed at the expense of hot oily legs for the rider.”

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And from the same thread, this beautiful machine (notice the brakes – that’s right – there aren’t any!!!):

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Which led to this build thread:

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I very much like this picture (used for frame layout).

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Which led to Halcyon Cycle Works, where one can get a frame, leaf spring fork or the whole enchilada:

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First things first – I have a bicycle project (100% human power) to work on, but dreaming doesn’t cost a nickel. I wonder if there was a board track sidecar class…