Continued development on my 'Bent

M

mwerner

Joined
Apr 23, 2002
Messages
5,354
I keep refining this beast. Here's the current configuration:



I have replaced the derailleur-cage chain guide with one that I fabricated from aluminum stock and roller-blade wheels. (you "machine" grooves in them) This is much smoother and quieter. Unfortunately, the top roller failed at about 2 miles. Seems I didn't pay attention to the guys who said to use HARD skate wheels. These were 74 durometer, I needed 88. I got the 88s today, and rather quickly made a replacement; they're much easier to work with too.

I also eliminated the clunky and complex dual-chain, dual crank setup. (couldn't get the gear ratios right) I routed the top run of the chain through a tube (all this courtesy of the home-built recumbent database) and now the original lower crank functions only as an idler wheel. I may get rid of it completely, replacing it with another skate-wheel roller.

At present, this thing is quite comfortable to ride, and will easily climb the hills I have on my usual training route. I'm already planning version 2.0, using an aluminum Y-frame as a base. This will give me V-brakes in back, and I plan to re-design the seat, stem, and front boom, which will bring me down to about 30 pounds.
That's competitive with commercial bents.
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:eek:

I was not expecting to see this.

Can you post a close up of the roller blade wheel mod?

Good luck.

T
 
Wow, that website has some great articles. Anyway, how do you figure out how long you need your chain?
 
My hat's off to you, mate! I regard myself as being lucky if I can mend a puncture and end up with a rideable bike and the same number of digits as I started with!

Excellent work.

maximus otter
 
Hehe- I just eyeballed it. Got real tired of breaking chain! Filthy things.... :D

There are standard methods for determining chain length; the Park Tool site has lots of interesting tech and repair articles. As I recall, with the chain on the big front ring and the biggest rear cog, the DR cage should be vertical.

That chain is composed of three different chains, and has been broken and spliced together in more places than I can remember. You can buy a "recumbent" chain (over 200 links) from Nashbar for about 14 bucks.
 
Here's a pic of the modified chain guide:

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The new, harder-compound wheel is the ugly orange one. Just took it for a ride, and it worked fine. I can get around my usual training course using all three front chainrings, going up the steeper hills in the granny gear (very slowly!)
Thing flies going down though, I have to put a computer on it.

Here's the foundation for version 2.0:

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A fine-quality "Pacific" Y-frame in glorious aluminum. Aside from the frame, every other part is made of the finest Chinese steel, and almost all of it will be thrown away!
 
I take it the roller blade wheels are fixed mounted? :confused:

Is your chain guide on the long run adding a decent amount of friction?

Cool setup! :cool:
 
That's a unique bike. I tuned in to see a Bentley automobile though. :)

So what advantages will your bike have over more traditional styled road bicycles? Faster? Better handling? More comfortable?

Honestly I don't think it can be as fast, and it seems very complicated - more moving parts and a longer chain make for increased friction and power loss. How's it lean in the corners? I'm open to any enlightenment...

-Bob
 
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