Retro-Direct Two-speed shiftless

[Badass#1]

Finally, here are some pics of my two-speed.
It is all stock parts, no frame modification. Both freewheels face forward, and the figure 8 in the chain around the tensioner allows it to flow either way with no contact.
Forward is low gear, backward is high gear.

[Skid Mark]

I don't get it but I know it works. How the heck did you screw two freewheels onto one hub?

[Badass#1]

That's the trick.
The first freewheel threaded onto the standard hub has some threads exposed. I threaded a bottom bracket cup (a flangless cup, steel) into those threads and thus had a bunch more space to thread the second freewheel onto the bb cup. This took a little balancing, since there are only a few threads available when you put the first freewheel on, requiring me to not fully tighten the first until the second was in place. At that point, they bind against each other and have held up for years. The first cup I used was aluminum and that shredded within 20 miles.
On another note, since I spend most of the time pedaling backwards, I find that I need to tighten the bottom bracket every so often.

[Skid Mark]

Sand on the beach. So simple so brilliant.

[lyledriver]

Good god what a hot build to make retrodirect!!!
*slow clap*

[Skid Mark]

So one of the freewheels is on backwards?

[Badass#1]

Both freewheels are threaded normally, and both drivel forward.
If you look at figure 2, you will see that the chain runs around the chainring and each end runs over a freewheel. So pedal forward, one freewheel is engaged and the other ratchets, pedal backwards and reverse the 2. So rolling, both freewheels ratchet, and it can't roll backward. 

I was buzzing around today and someone on the sidewalk just couldn't understand "Hey, you're pedaling the wrong way! [and going forward]"

Its great.

[dutch1]

it really is great. so much fun to ride pedaling backwards, even if it seems like such a simple thing

[GnarLee]

Damn i love that bike.  The next step... one that ONLY goes BACKWARDS.

[justa]

wow

[NRG]

Nice!  Is it loud to ride what with one cog always freewheeling?
--D

[Badass#1]

It's a pleasant sort of constantly ratcheting sound.