Recumbent - Winter project finally complete.

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View Full Version : Winter project finally complete.


Dan Burkhart
12-22-07, 01:09 PM
Hi All
I'm not new to the bike forums, but I have not posted to the recumbent section before. I have been off my bent for a few years as it became a back burner project through the building and opening of my shop.
So when things slowed down this fall, I decided it was time to dig out all the parts and assemble it.
The base bike is a Quetzal C105. It originally had a 105 speed drivetrain consisting of a 7 speed rear wheel cluster, a 5 speed mid drive and a triple up front.
I wish I had some photos of the original build, but I wasn't too much on photography back then.
Anyway, here's some photo links of the current incarnation.
With no room on the bottom of the chainstay, the reaction arm for the Rohloff hub had to be mounted on the back of the seatstay. A bit cludgey, but it works.
http://tinypic.com/view.php?pic=7x8ni2w&s=1
Here is the shifter mount detail.
http://tinypic.com/view.php?pic=81jlead&s=1
And the cable routing to the shift mech.
http://tinypic.com/view.php?pic=6lsgggz&s=1
http://tinypic.com/view.php?pic=6s87bzq&s=1
And here she is fully assembled. I just need to get some John Deere decals, and I'm all set.
http://tinypic.com/view.php?pic=870ke3p&s=1
I just couldn't wait for dry road to do the test ride. Got the back of my neck wet, but so what.
http://tinypic.com/view.php?pic=867vqps&s=1
http://tinypic.com/player.php?v=6o47143&s=1
Glad to be back on the bent.


STEEKER
12-22-07, 01:25 PM
That looks cool ! sweet bike ,nice build

gnome
12-22-07, 01:33 PM
Looks nice and shiny. Hope you enjoy riding it when the weather improves.


Dan Burkhart
12-22-07, 02:17 PM
Looks nice and shiny. Hope you enjoy riding it when the weather improves.

Thanks. It's just a rattle can paint job. Actually came out better than I anticipated, but close inspection will reveal the flaws.

FLYBYU
12-22-07, 05:41 PM
Nice! I like the pait job. One question, what is that fitting on the frame in front of the handlebars for?

Dan Burkhart
12-22-07, 05:59 PM
Nice! I like the pait job. One question, what is that fitting on the frame in front of the handlebars for?
That is where the computer and heart rate monitor will be mounted. It's just an ABS Y pipe tailored to fit and JB welded in place. The reducer bushing will accept a 1/2 pipe thread plastic pipe about 1 foot in length.
Before the rebuild, I just had it hose clamped in place. Worked well but looked ugly.
When I get it rigged, I'll post more pictures.

FLYBYU
12-23-07, 01:23 AM
Ah, I see, I thought it was part of the frame, but now it makes sense.

Dan Burkhart
01-15-08, 12:41 PM
Well, I finally got a chance to give her a shakedown ride, and it became almost instantly apparent that my chain tensioner set up was just not going to work.
http://tinypic.com/fullsize.php?pic=870ke3p&s=1&capwidth=true
If not for the seal drag on the Rohloff, I'm sure it would work OK, but every time I back pedalled even a little bit, the top chain would droop off the idler. So, after a bit of head scratching, I decided the best course was to go back to a mid drive, seeing as how the mounting system, (A bottom bracket shell,) was already in place.
http://tinypic.com/fullsize.php?pic=7324r5l&s=1&capwidth=true
Then, it was a matter of altering a freewheel by dissassembling and removing the pawls,grinding the teeth off a large sprocket, and re-arranging the cogs to make the large cog into a separator disc.
http://tinypic.com/fullsize.php?pic=6x6ilv6&s=1&capwidth=true
To mount the mid drive, the freewheel was threaded onto an adjustable bb cup, (They are threaded the same)
http://tinypic.com/fullsize.php?pic=80zaq7m&s=1&capwidth=true
http://tinypic.com/fullsize.php?pic=6y4w6r4&s=1&capwidth=true
This set up offers the added benefit of having the chain line on the front chain moved inboard substantially,and using a small chain ring. Should help to reduce the chain tattoo on my right calf.
http://tinypic.com/fullsize.php?pic=8fmsg1t&s=1&capwidth=true
It also gives me the choice of 4 ratios to change between on the mid drive. Although there is no shifter mechanism, it's a simple enough task to slip the chain from one cog to another when conditions warrant it.
The gear inch range with this gearing ranges from about 14 to 105. Adequate, I should think.
Another issue, albeit a minor one, is that the Rohloff shifter mounted vertically like this must be shifted with the outer part of the hand rather than the inner part as in a normal setup.
http://tinypic.com/fullsize.php?pic=6kixefl&s=1&capwidth=true
Since the pinky finger is much weaker than the index finger, it is somewhat difficult to manipulate. I expect this will improve with more use as that part of the hand is strengthened.

Dan Burkhart
01-16-08, 08:56 AM
OK, this is just a little bit embarassing, so I'll point it out before someone else does. I'm sure some of you already figured it out, but were just too polite to get a dig in.
I did the math backwards on the transfer ratios on the mid drive, and in my thick headedness, I forged ahead in the wrong direction. What I created was a super gear reduction rather than an increase. DOH!
So, I revamped the mid drive to comensate.
http://tinypic.com/fullsize.php?pic=851lcg9&s=1&capwidth=true
http://tinypic.com/fullsize.php?pic=8e9trhu&s=1&capwidth=true
I still have much more reduction available than I will ever need, (enough to void the Rohloff warranty),but I have also acheived enough of a step up to get me up to 102.8 gear inches with a 39 tooth gear ring.
The only real flaw I can see with this system is the tooth profile on the cogs is cut to be pulled by the chain, not having them pull the chain, but it should work OK in spite of that.
http://tinypic.com/fullsize.php?pic=7xn34hv&s=1&capwidth=true