freewheel adapter for square taper spindle

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MaxPower

MaxPower

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I'm doing a project with a tandem bike and want to use the rear riders bottom bracket as a jackshaft. I'm having problems finding a dual sprocket. I need a freewheel adapter for a square taper spindle that can accommodate two freewheels. I've attached a picture of what I'm thinking.

Also, If it use a Keyed shaft with a two freewheel adapters, how would I adapt the shaft to the bikes bottom bracket. Do they make bearings that can thread into the bottom bracket?
 

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bairdco

bairdco

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Aug 18, 2009
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i dunno about the freewheel adapter, but you can get a three piece crank bottom bracket adapter (american to european conversion, technically) from bikepartsusa.com for $17.58...Pyramid 3 pc, Bottom Bracket Conversion Kit | BikepartsUSA

i know they make sealed bearing set ups, too, and there's a kit that has two aluminum pieces that bolt in to your frame so you can run any euro bottom bracket you want, but those are more spend-y.

hope this helps.
 
MaxPower

MaxPower

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yeah... not much help. I was thinking that I could find a bolt that fits freewheel threads and then find someway to cut the square taper into the bolt. Does anyone know if a bolt like this exist or if a mechanist can cut a square taper into a bolt? I was also thinking of starting with a tapered crank and cutting the crank off and treading it. What is the thread size of a freewheel? how would I describe it to someone I wanted to buy it from?
 
Blakenstein

Blakenstein

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Sep 15, 2009
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Spindle??????????????? what ,......for your disk brake?????hahahahahahahahahahahahahahahahahahahahahahahahlololololololololololololololololol you better get your spider gears working firsthahahahahahahahahahahahahahahahahahahahahahahlololololololo::):):):)
 
Junster

Junster

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SBP sells a set of cranks, hvy duty freewheel, duel sprocket setup for their shift kit. It would be only on the right side. If you used a shift kit and a extra set of cranks, fw, sprockets for the rear pedals you could get it to work.
 
NEAT TIMES

NEAT TIMES

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Max Power, Interesting!! You Do Have A Bit Of A Challenge. If There Is A Way To Use Sealed Bearings In The Bottom Bracket Housing And A Keyed Shaft With Staton Free Wheel Adapters. Bearings With Outer Snap Rings. Then You May Need A Wider, Longer Front Pedal Spindle To Line Up With Back Sprockets. When You Go To A Machinist, It Gets Expensive In A Hurry. Where Is Your Girl Friend Going To Put Her Feet?? Or Will It Be A Cargo Bike? Good Luck. We Will Be Watching You!! Lol. Ron .cvlt1
 
Dan

Dan

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May 25, 2008
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Can be done Max! Wish I could draw with PAINT. Another thought (I been thinking about this for a while) Is a jack shaft over to the right side and adding a small chain ring (Freewheeling if necessary) Ebikes have had em for years. e bike freewheeling chainring - Google Search

There is always taking it to a local machine shop and have that bit made but would be a good deal of cash.

Tandems vary, so not sure what would work best/cheaper. Can't wait to see what you do. Post pics and buy bonds!

.flg.
 
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NEAT TIMES

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Max, I Went To "vxb.com" (bearing Supplier). If Your Bottom Bracket Housing Is The Smaller Type= Threaded For 1 3/8" 24 Tpi. These Bearings May Just Be Your Ticket. They Are 5/8" Id For 5/8" Keyed Shaft And 5/8 Bore Staton Free Wheel Adapters. Od Is 1 3/8" Flanged. Part Code Is "kit 8758" @ $3.95 Each. If You Housing Is Large, Give Me The Id. Hope This Helps. Ron .cvlt1
 
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NEAT TIMES

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Max, Have A Nice Tandem Myself. Been Trying To Decide What To Do With It. One Thought Was To Use The Rear Seat Post For A Back Rest, Mount Seat Low, Ahead Of Rear Seat Post, Then Have My Arms Lengthened!! Lol Ron
 
Junster

Junster

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Ok Max, any crank with a sprocket attached could be put on the left side and the right side rear and cut the pedal arms off. With aluminum ones it would be easy to make them look nice. That takes care of the motor drive. Then you can use the freewheel cranks from SBP on just the front bottom bracket.

Sick Bike Parts LLC - Performance Parts for Your Motorized Bicycle

You will need the crank arms, Hvy duty freewheel. Your choice of sprocket and the spocket mounting hardware kit or just goto the hardware store for 5 small bolts cause you will only need one front sprocket.

The rear wheel freewheel will take care of coasting, the front so the pedals don't spin under motor power and the motor clutch will do if you have to pedal power. GL
 
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jay sawdust

jay sawdust

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I think perhaps our "elite" member has his nos hooked up incorrectly....i appauloud your use of grafics....and although i have no input.....admire your use of the forum.......aloha J
 
NEAT TIMES

NEAT TIMES

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Junster, You Made It To Easy. Lol. When He Was Wanting Two Free Wheels On The Back, I Was Trying To Do That. Then His Front Chain Would Not Be Spinning All The Time. Your Solution Is Simpler. Jay, Should I Take Offence With Your Remark "elite" Member Nos Incorrect?? Please Respond. Ron
 
MaxPower

MaxPower

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Junster said:
Ok Max, any crank with a sprocket attached could be put on the left side and the right side rear and cut the pedal arms off. With aluminum ones it would be easy to make them look nice. That takes care of the motor drive. Then you can use the freewheel cranks from SBP on just the front bottom bracket.
Click to expand...
I thought of doing that too but I did not want to have the front sprocket spinning (more friction). If all else fails Ill do that. also the tandem bike I have has one piece style bottom brackets (2") so it would be an added expense to put a conversion kit on both bottom brackets. I found some BMX bearings that fit the 2" bottom bracket but the inside diameter is 22 mm. Staton sells 7/8" keyed shaft adapters. Does anyone know if a 7/8" shaft will fit a 22 mm opening diameter? its a difference of only 0.008858268". Are tolerences that critcal?
 
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