Modifying Friction Drive To Accept GEBE components

Discussion in 'Motorized Bicycle General Discussion' started by 5-7HEAVEN, May 9, 2010.

  1. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    Trying to recycle friction drive kit to accept GEBE parts.

    I'm modifying two BMP/Staton friction drive kits to make "better mousetraps".

    My first DIY project involves leaving my FRONT friction drive housing in place, relocating the engine, using the BMP axle as a jackshaft and installing chains and sprockets. Engine gets a 5:1 gearbox and relocates atop the friction drive housing. That project is pretty straightforward in my head and progressing well. Pictures to follow upon completion.

    Next project is leaving my REAR friction drive kit in place. New engine motor mounting holes are drilled on the other side of the drive housing. That way, the engine and drive will spin counterclockwise and turn the rear wheel. The BMP clutch drum, axles and bearings remain in place. Friction roller is removed and substituted with the GEBE drive pulley. GEBE drive ring mounts normally. Since the engine and drive pulley is closer than the standard GEBE position, a shorter belt is installed. Belt is tensioned by adjusting the friction housing's modified rear supports, like two of these:

    http://www.staton-inc.com/Details.asp?ProductID=2675

    My project SHOULD work; expenses would be about about $125. The drive can be changed back to friction drive at no added expense.

    After the drive pulley is perfectly aligned with the drive ring, either setscrews or welding can secure its permanent position.

    My questions for now is...

    Does anyone know the INSIDE diameter and OUTSIDE diameter of the GEBE drive pulley? Does it use a keyway? Sorry, I've never seen a GEBE kit.

    If the pulley's 1/2" ID, then it'll slip right onto the BMP shaft. If it's keyed, I can either machine the BMP for keyway or tackweld the gear onto the shaft.

    Please feel free to comment, either negatively:-|| laff

    or positively.dance1
     
    #1 5-7HEAVEN, May 9, 2010
    Last edited: May 9, 2010
  2. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    I've been informed that the GEBE drive pulley's ID is 5/16" fine thread. :detective:

    That won't slip onto my 1/2" diameter jackshaft. Unsure if this pulley can be drilled 1/2", then welded onto the shaft. .weld

    Does anyone know what the OD of any or every GEBE pulley is? I need to know the diameter where the belt rides, and the diameter of the outer lip. scratg

    Maybe I'll be needing to search for a pulley and belt elsewhere, which would work well with the GEBE ring's belt grooves. :detective:

    TIA.
     
    #2 5-7HEAVEN, May 9, 2010
    Last edited: May 9, 2010
  3. Smallwheels

    Smallwheels New Member

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    Don't use a GEBE pulley system. It is crap. I'm fed up with mine and will be converting to a friction drive as soon as I source a new clutch for my Tanaka PF 3300.

    One day when I've got some time I'll write my complete experience with the GEBE kit. They're fun at first. Then the broken spokes and wheel rebuilds start to become a regular experience no matter how well you watch your wheel or wire wrap your spokes where they cross. The belts and drive pulleys wear out within 1500 miles too.


    Smallwheels
     
  4. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    Smallwheels, I'll be waiting to hear your GEBE story.:-||

    Summer's here, so I'll have extra time for my bicycle projects until night school starts in August.

    I've purchased the GEBE drive ring, so that's a start. I already have the BMP driveline and have found two online stores with $10 HTD pulleys and $11 belts. Just need to find the right pulley with 1/2" bore diameter. If I'm lucky and the OD is less than 1.375", I'll be able to remove the assembled driveline from the friction housing in one piece.

    So far, this prototype should cost less than $100, which is a pleasant surprise. It can also revert back to friction drive at no extra cost.

    That's freaking awesome!dance1
     
  5. NEAT TIMES

    NEAT TIMES New Member

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    5-7, I Started Abelt Drive A Yr Or So Ago And Never Finished. Still Think About It Now And Then But I Like The Bigger Engines And That May Be To Much For The Belt System. If You Are Planning On Going Ahead Wth Your Plans Here Is How In Mho To Do It. I Just Miked My Drive Cog From Golden Eagle. It Is 1 Inch In Diamiter With The Lip`s On Each Side.. It Is The 14 Tooth, Largest One They Sell. The Easiest Way Will Be To Put Your Locking Collars And The Bearing Snap Ring`s On The Inside Of The Housing= To Hold Shaft In Position. Then Figure Out Your Length. It May Be Right On. Now You Need To Take The Shaft To A Lathe And Have Them Bore And Tap End To 5/16 Inch Fine Thread To The Correct Depth. Get A Grade 5 Allen Set Screw About 1 Inch Long To Screw Into The Shaft And Screw On The Cog. Make Sure The End Of The Shaft Is True, They Can Check It In The Lathe. You Will Not Need A Lock Nut Or Lock Tight, The Motor Will Keep It Tight. Some Pic`s Of The Clutch Setup I Came Up With. I Don`t Remember What Size Engine You Have. The More I Mess With This Stuff, The More I Respect My Friction Drives. Was Planning On Turning The End Down Smaller On The Allen Set Screw So I Could Install The Outer Bearing For Extra Support. A Spring Loaded Tensioner Would Be Very Necessary In Mho. In The Pic`s The Piece That I Screw The 5/16" Allen Set Screw Into Had The Small 9 Tooth Sprocket #25 Chain Cut Off In The Lathe And Then Bored And Tapped For The Set Screw. Layed In Bed Many Nites Thinking How To Do It Cheap. A Lot Of My Motors Have That Little Bell Housing With The Clutch Drum On Them, Some Have The Outer Bearing On Them. THERE IS ONE MORE PIC BUT WILL NEED TO BE RESIZED. Ron .cvlt1
     

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  6. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    Thanks for your feedback, Ron! I see you were trying to use the pocketbike's outer housing to mount the stock GEBE drive pulley. Most of what I'm trying to use is on the BMP friction drive kit:

    BICYCLE ENGINE PARTS, MOTORIZED BICYCLE PARTS

    I'm using everything in the BMP kit except the friction roller. An HTD drive pulley similar to GEBE's pulley will replace the friction roller on the shaft. If I find a pulley with a 1/2" bore diameter, then absolutely no machine work is necessary.

    I have a used Staton wheel with 12g spokes that should work well with this project.
     
    #6 5-7HEAVEN, May 16, 2010
    Last edited: May 16, 2010
  7. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    I'll be using a 2.2hp Mitsubishi on this prototype. Care will be taken to pedal from a standstill before applying the throttle.

    Waiting for the GEBE drive ring to arrive. Still searching for the correct-size HTD drive pulley.
     
  8. NEAT TIMES

    NEAT TIMES New Member

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    5-7, Good Morning. I Thought It Was Under Standable That I Know You Are Using The Bmp. I Have A Couple Of Them. This 14 Tooth Htd Has The Center Pressed Into It. I Just Miked It With My Digital Calipur. It Seems To Be About .550", Which Would Be Too Loose On The 1/2" Shaft. One Place It Measures .498". As You Already Have The Keyed Shaft, You Could Spend A Painfull Hour Or So Filing A Keyway Into The Cog. If The Hole Is Not To Large. Then You Could Have The Cog Inside The Housing, Which Would Be Much "gooder"! Lol The Geebe Shows The Spring Tensioner Close The The Cog So It Gets More Belt Wrap On The Cog. You Could Screw In A Bolt And Set The Cog In A 9/16" Or 5/8" Socket And Squeeze It Out In A Vise Or Pound It Out. My Cog Looks Like The Protruded Side Should Be In The Socket. Just Trying To Help. Maybe Make A Free Call To Ge About Spokes And The Size Of The Slots In The Wheel Sheave. The 43cc Mitsi Was My First Motor, Still In The Box For Over 2 Yrs, Too Nice To Use!! Good Luck, Ron
     
    #8 NEAT TIMES, May 16, 2010
    Last edited: May 16, 2010
  9. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    Good morning, Ron. Thanks for sharing the drive pulley's specs. I'm still searching for the right pulley to slip onto my 1/2" keyed shaft(which hasn't arrived yet). I know there HAS to be a $12 one that'll work for me.

    The GEBE drive ring is meant to be used with 12-14g spokes. It should slip right on.
     
  10. NEAT TIMES

    NEAT TIMES New Member

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    5-7, If Yours Works Out, I May Finish Mine, If I Live Long Enough! Lol. Bought A Mongoose 450 Watt Electric Bicycle The Other Day For $50. Locally, Non Working. Thought The Frame Would Be Good For A Jackshaft Build With The Longer Frame For The Battery Pack. Now As I Look It Over, It Will Be Very Easy To Make A Rear Axle Mount Gas Engine Drive. Just Redrill A Set Of Holes For The 5:1 Ratio Gear Box And Install A Larger 36 Tooth On The Axle Free Wheel. I Put An Add In Craigslist For Non Working Electric Mongoose`s. Hope You Don`t Mind My Posting This. This Would Be The Cheapest "good" Build That I Can Think Of. Pic`s. Will Start A Build Thread When Starting. Keep Us Posted On Your Progress. Your In Hi.?? Posting pic of clutch, saw those shoulder bolt`s on ebay for $4. ea. with the head for the spring. they would be great for geebee spring tensioner as they would cam over like the golden eagle. Ron .cvlt1
     

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  11. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    Good score on the electric bike, Ron. No probs at all showing it here.

    It'll be an interesting build for all, if you install gas engine to run with electric motor!

    I have one of those clutches laying around that I could scrounge from.

    For belt tensioning, I'll be adjusting my rear support rods to stretch the belt. Adjustment will be locked in solid, because I'm using 18" of 3/8" allthread as the support struts. This SHOULD work; if not, a simple tensioner can be bolted on, near the drive pulley.

    Yes, I'm in Hawaii. Days are longer, night classes are out for the summer. This'll give me more time after work for my bike project.dance1
     
  12. 5-7HEAVEN

    5-7HEAVEN Well-Known Member

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    To solve the major problem of replacing the belt, a spare belt will be secured around the axleshaft, ensuring that no pulleys or collars rub against it. If/when the main belt breaks, the spare is easily dropped into place and adjusted for tension.

    I inquired with an online company who can fabricate custom pulleys. I might order a twin pulley which is siamesed together, using a 14-tooth and 15-tooth. To change pulley size, simply loosen the drive pulley, align the new pulley size to the belt and tighten everything up.

    Voila! New gearing ratio in minutes!dance1
     

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