Does anyone know how to make a stock bottom bracket work as a jackshaft? Any particular bearing size?
bottom bracket jackshaft
- Thread starter jazz2561
- Start date
Keeping in mind not all bottom brackets are the same - I used 499502HNR sealed bearings w/snap rings (5/8" ID x 1-3/8" OD, same as the shift kits) & after lightly honing down the threads in the BB they pressed right in. Add a 5/8" keyed shaft, "BMX" freewheel, threaded freewheel adapter, lock collars & 5/8" keyed sprockets of your choice;
pedal driven: http://youtu.be/U10xLqTekOw
engine driven: http://youtu.be/_GTS0xG8BPM
pedal driven: http://youtu.be/U10xLqTekOw
engine driven: http://youtu.be/_GTS0xG8BPM
Here is how I did mine:
http://motorbicycling.com/showpost.php?p=573529&postcount=8
The bearings in the bottom bracket are 52mm OD x 25mm ID sealed ball bearings.
http://motorbicycling.com/showpost.php?p=573529&postcount=8
The bearings in the bottom bracket are 52mm OD x 25mm ID sealed ball bearings.
FFV8 love your idea. Here is another Goldy did ..............Curt
http://motorbicycling.com/showthread.php?t=28747
http://motorbicycling.com/showthread.php?t=28747&page=14
The band might not be necessary if your clutch drum sticks out past the hub far enough (about 1/8")
There was a hole already in my clutch hub that I simply tapped 1/4 UNF to fit the pawl screw...upon final installation, I peened the end of the screw over to prevent it from unscrewing and falling out. The roll pin prevents the heavy side of the pawl from contacting the drum when running and also provides a point to fasten the return spring. I use a rare earth magnet to hold the pawl in the disengaged position when pedaling , or pushing it around. Also the heavy end of the pawl rests on the central part of the clutch hub when in the engaged position, I figured this would give it some extra strength and take some of the strain off the drum.
http://motorbicycling.com/showthread.php?t=28747
http://motorbicycling.com/showthread.php?t=28747&page=14
The band might not be necessary if your clutch drum sticks out past the hub far enough (about 1/8")
There was a hole already in my clutch hub that I simply tapped 1/4 UNF to fit the pawl screw...upon final installation, I peened the end of the screw over to prevent it from unscrewing and falling out. The roll pin prevents the heavy side of the pawl from contacting the drum when running and also provides a point to fasten the return spring. I use a rare earth magnet to hold the pawl in the disengaged position when pedaling , or pushing it around. Also the heavy end of the pawl rests on the central part of the clutch hub when in the engaged position, I figured this would give it some extra strength and take some of the strain off the drum.
Actually it is an off the shelf Silver State frame with a standard bottom bracket. I started with his most basic frame kit to build that bike.
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Sportscarpat sells a nice bolt on unit that’s tough & adjustable...
About 2/3rds down the parts bikes/page- http://www.sportsmanflyer.com
About 2/3rds down the parts bikes/page- http://www.sportsmanflyer.com
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So were did you get the shaft and bearing from looks real good.Keeping in mind not all bottom brackets are the same - I used 499502HNR sealed bearings w/snap rings (5/8" ID x 1-3/8" OD, same as the shift kits) & after lightly honing down the threads in the BB they pressed right in. Add a 5/8" keyed shaft, "BMX" freewheel, threaded freewheel adapter, lock collars & 5/8" keyed sprockets of your choice;
pedal driven: http://youtu.be/U10xLqTekOw
engine driven: http://youtu.be/_GTS0xG8BPM
The shaft & bearings I picked up at a local hardware store, it's pretty common stuff 
Bottom bracket jack shaft.......easy with a tandem
You can use it with or without the stoker cranks with an SBP BB and their shift kit parts....
You can use it with or without the stoker cranks with an SBP BB and their shift kit parts....