Make:

• "My Speed" bike vest
• Tall Bike Extravaganza
• Yellow Bike Project's Bike-Powered Move
• DIY: Bicycle "Porteur" Rack
• How To: Build a motorized bicycle
• Beijing bicycles

Looks good if you don't try to steer, like, for instance, you need to do to stay on.

Me and a couple of freinds made one of these before and it was impossible to ride, in the end we welded 2 bikes together.

Posted by: Marc de Vinck on July 14, 2008 at 6:24 AM

@impossible

Out of curiosity, what made it impossible to ride?

@Marc de Vinck: Look at the chain line to the rear bike. Unless the fork is welded in the steerer on the rear bike, preventing it turning, the chain will deflect sideways.

And if you fix the middle wheel so it can't pivot, then the bike won't be able to turn.

It looks cool, and it probably is eye-catching to ride, but it'd probably be better to simply mount up two bikes without the idler chain between 'em, and let each rider pedal independently.

Posted by: Marc de Vinck on July 14, 2008 at 8:10 AM

@Captain Observant

So the Achilles Heel is the idler chain.

I know that co-riders are fairly popular and seem to work well.

http://www.amazon.com/Adams-Original-Folder-Trail-Titanium/dp/B000ALJ5FA

Why stop at 2???

After looking over the Instructable (doesn't always cooperate at work), I see that they've bolted the fork through the steerer tube of the rear bike. And they admit it's very difficult to turn around.

Still, an interesting project, and probably really eye-catching to watch someone (try to) ride it...

Even if the rear fork/steering tube is immobilized to keep the chain from falling off, the whole thing about three wheels in line will make it difficult to steer, it seems. Normal tandems steer on two "pivot pints", being the front and rear wheels. With three wheels, the rear two being fixed and inline, are acting as a single, very long, "pivot point".

I wonder if it would work if the drive chains for each bike were left independent and the stoker was allowed to turn? This would seem to fix both the steering and chainline problem, and be simpler to implement. The rear bike would act more like a trailer, it's fork acting more like a trailer hitch

I built one of these yesterday. It did ok for a short while, but the two frames pivot against one another at the middle axle on any uneven ground. After a while this can cause the loosening of the nuts there. Some sort of bushing or bearing system is needed to allow motion without the axle coming loose. Be careful out there guys.

Posted by: Marc de Vinck on August 25, 2008 at 12:04 PM

Thanks for the information. Do you have any pictures or better...videos!

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