3 Piece Wide Crank??

Discussion in 'Motorized Bicycle General Discussion' started by jimraysr, Jun 12, 2008.

  1. jimraysr

    jimraysr New Member

    Joined:
    Apr 19, 2008
    Messages:
    78
    Likes Received:
    0
    I am building a Honda / GruBee on a new Schwinn Searcher. It has enough frame space for the engine and mount, BUT the crank bearings are around 1 1/2" and I don't think the one piece crank in the kit will go in the bearing case.

    I have seen wide 3 piece cranks pictured in other kits, but have not found them available as a separate item.

    Has anyone had any luck in finding a wide 3 piece crank?

    Thanks, Jim
     
  2. Easy Rider

    Easy Rider Santa Cruz Scooter Works

    Joined:
    Jan 15, 2008
    Messages:
    2,148
    Likes Received:
    4
    Jim, Shimano makes different width size crank hubs. I put on the widest one they make. Plus you can use shorter crank.
    Good luck on your project.
     
  3. nogoodnic

    nogoodnic New Member

    Joined:
    Jan 29, 2008
    Messages:
    509
    Likes Received:
    0
    You might also want to keep an eye out for a junk Schwinn Stingray (chopper style). They have wide 3-piece cranks on them to get around the 4.25 tire...Kelly
     
  4. ocscully

    ocscully New Member

    Joined:
    Jan 6, 2008
    Messages:
    373
    Likes Received:
    0
    Jim,

    I would contact the the folks you have seen selling the kits with the wide 3-piece cranks and ask if they will sell you a set. I did this several months ago and a couple of them said they would sell a set of cranks. I didn't end up making the purchase though as I've decide to modify my existing crankset. The problem with both solutions mentioned above is will they get you wide enough? The engine & gearbox measure in at 9.5-10 inches wide. The longer BB spindle will probably be to short and it will also push the standard crank sprocket out to far causing chainline problems for the pedal drive.

    Revolution Cycles has a pair of wide 3-piece cranks they are offering but they seem really mickey mouse to me as they use old school cotter pins to secure them to the BB spindle. And then there is the problems that many people in have had with the seller. His reputation is not good. Buyer Beware!

    ocscully
     
  5. jimraysr

    jimraysr New Member

    Joined:
    Apr 19, 2008
    Messages:
    78
    Likes Received:
    0
    I can see where the chopper crank would also require the sprocket to be out as well. Seems like the offset in the crank is the way to go if available. Actually I really like the OEM sprocket. It is self shielding and very clean looking. I had already thought of the old trick of a rubber band on a long pant leg to keep it out of the chain. Shorts eliminate the problem around 7 months a year here. Our kids wore shorts all winter long when they were in school. Don't think that will work for me. )

    Revolution was an early attraction being so close, but fortunately I read enough to go to Florida for my kit.

    Thanks guys for the suggestions. Will welcome any more anyone comes up with. Really looking forward to actually riding past a few gas stations. The canal system here offer bike trail shortcuts cars and others would die for. )

    Jim
     
  6. regleo

    regleo New Member

    Joined:
    Jun 17, 2008
    Messages:
    4
    Likes Received:
    0
    has anyone tried to heat the crank arms and bend them to make them offset ????
    i bought a universal offset crankset but the bearing cups look to be too large for my scwinn frontier 23"frame .im trying to put a pull starter and a centrifugal clutch on my 80cc kings motor ..thanks
     
  7. jimraysr

    jimraysr New Member

    Joined:
    Apr 19, 2008
    Messages:
    78
    Likes Received:
    0
    I found a dealer who had a set of wide cranks. They are square taper, so should fit in place of the aluminum alloy ones that Schwinn put on. Got a Parks crank removal tool from a local bike shop for $11. It threads into the crank and has an internal screw that pushes the crank off the spindle. Of course you have to remove the retaining screw / bolt under the plastic cap first.

    If you straight cranks are aluminum, don't think you will be able to bend them. The wide set are chrome plated iron.

    Tip on using the crank removal tool. As mentioned, remove the plastic cap, then the retaining bold / screw, then thread the very fine threaded tool into the crank threads. I found it easy to be sure I didn't cross thread by turning the tool CCW till I felt the top thread of the crank drop the bottom thread of the tool down, then turned it CW into the crank till it bottomed. Then you can screw in the internal tool removal bolt to push the crank off the square spindle. It has a button on its end that turns and helps prevent binding of the tool to the spindle. Hope that helps someone.

    One other note the tool I bought has a lever attached to the internal push off bolt. The lever will not clear the wide crank, so the lever must be bent up to clear the crank. The rest is duck soup!

    Jim
     
  8. Fosscati

    Fosscati New Member

    Joined:
    Jul 3, 2008
    Messages:
    36
    Likes Received:
    0
    Jim, the big problem is that too many kit suppliers offer only the 3 piece crank when nearly all cruisers and all Schwinn cruisers have a 1 piece crank.
    I have a few 3 piece cranks left over from 4-stroke kits. They are really useless and to fit them on a Schwinn Cruiser you need a $60 adaptor to make a $4 crank fit. The crank arms are kiddies cranks and too short to give proper leverage. I'll send you my 3 piece if you send me your 1 piece. The 1 piece has cups & bearings & the 3 piece has only a wide spindle with a Euro bb, 2 crank arms, two nuts & 2 plastic plugs. How come I've never had a problem fitting 1 piece cranks on Schwinn cruisers. Is your Schwinn not a cruiser? I'd say get a cruiser if you have a 4-stroke frame mount.
     
  9. jimraysr

    jimraysr New Member

    Joined:
    Apr 19, 2008
    Messages:
    78
    Likes Received:
    0
    I found a three piece set of cranks. They were full sized approx. 6.5” center to center. 44 tooth sprocket attached to the right crank. They are the square taper and replaced the Schwinn ones without having to change the lower bracket internal assembly.

    The bike is a "Searcher" with a 1.5" lower bracket. None of the Schwinns I saw when shopping had a 2" bracket that the one piece would fit. A dealer (FL) mentioned when I was looking for the 3 piece cranks that the ones he had seen were the old square style that had wedge pins, so these I got must be a newer style that are retained by a bolt in the end of the spindle.

    The Searcher frame has just enough space for the Honda GXH50. Had to grind out the front aluminum mount part to fit the approx. 2" lower tube and allow the mount to drop in enough the engine would fit. Drilled and tapped the front mount to fit a 2" muffler clamp (discarding the U bolt) that I saw some smart guy did in an other post. Used a piece of sheet metal covered wt. duct tape to guard the frame and paint from the muffler top bracket.

    Could not use the slotted engine mounts in the mount, but used a straight edge to find the sprocket alignment with the driven one on the rear wheel.
    Engine had to go almost to the front edge of the mount to give some space to remove the air cleaner cover. Drilled the mount and the front aluminum adapter to the bolt pattern of the engine and used bolts from the underside. Good thing with that arrangement is the engine can be removed without the mount.

    The Schwinn runs the brake and derailer cables under the top tube and the choke lever (plastic) could not be operated. Cut off the top of the lever and drilled and tapped the plastic shaft and inserted a 1" X 6-32 bolt that works fine and both points at the operating icons and the head acts as handle.

    Jim
     
  10. regleo

    regleo New Member

    Joined:
    Jun 17, 2008
    Messages:
    4
    Likes Received:
    0
    I Figured If I Make Aanother Down Tube With A Bracket On Each End .i Can Use Ubolts. And Raise The Motor Up To Clear The Pedals I Have The Room Because Its A 23in Frame I'm In The Process Now I Let You Know How It Works Out
     
  11. DOC BOLM

    DOC BOLM New Member

    Joined:
    Aug 21, 2008
    Messages:
    681
    Likes Received:
    0
    Just bent mine ,works great,clears rope start 1/2 inch.watch your flame,take tank off and drain carb,dont want to call 911. HARLEYS DAD
     
  12. Fosscati

    Fosscati New Member

    Joined:
    Jul 3, 2008
    Messages:
    36
    Likes Received:
    0
    Jim, I think the 1 piece will work but you may need different bearings for it. The 1 piece fits the other Schwinn Cruisers without changing the bearings.
    The 3 piece is a mongrel of a crank and it's only practical use is as a weight for deep sea fishing. I have 2 lying around here.
     
  13. Biker Mike

    Biker Mike New Member

    Joined:
    Mar 21, 2008
    Messages:
    143
    Likes Received:
    0
    Hey DOC, some pics of this mod would be a great help if you can. I'm considering doing the same thing. :ride2:
     
  14. HoughMade

    HoughMade New Member

    Joined:
    Apr 15, 2008
    Messages:
    624
    Likes Received:
    1
    I used short crank arms, but likely that will only work well if you do not plan on pedaling much. I built my bike to mimic an early motorcycle and to cruise on motor power- exercise is found elsewhere.

    With the short crank, the arms do not reach the engine and are below it. The arms clear the rear bolts on the Grubee mounting plate by 1/4" on each side even using a standard bolt (though 7mm, not the stock 6mm), a washer and an 18 ga metal plate to pretty up the plate.
     
  15. jimraysr

    jimraysr New Member

    Joined:
    Apr 19, 2008
    Messages:
    78
    Likes Received:
    0
    The offset cranks I got from Spooky Tooth were the same length as the original Schwinn crank arms (6" +). They fit the spindle just fine.

    The problem with the one piece and a 1 1/2" bottom bracket looks to be the elbow won't fit through the small space?

    Jim



     
  16. Biker Mike

    Biker Mike New Member

    Joined:
    Mar 21, 2008
    Messages:
    143
    Likes Received:
    0
    Hey Doc, Here are the pic's you wanted me to post. Thanks again for your help. (^)
     

    Attached Files:

  17. DOC BOLM

    DOC BOLM New Member

    Joined:
    Aug 21, 2008
    Messages:
    681
    Likes Received:
    0
    The left pedal is now 3/4 inch shorter than the right. If you think it will be a problem go to ebay #110288044785 pedal risers, and use only if needed.HARLEYS DAD p.s the brown lab in photos is harley
     
  18. Biker Mike

    Biker Mike New Member

    Joined:
    Mar 21, 2008
    Messages:
    143
    Likes Received:
    0
    How about bending the other side to match??? Just an idea....:confused:
     
  19. jimraysr

    jimraysr New Member

    Joined:
    Apr 19, 2008
    Messages:
    78
    Likes Received:
    0
    Both my straight (Schwinn OEM) and offset China 3 piece cranks are 6" plus center to center. (center of spindle to center of peddle)

    Is this the length of your cranks before you offset the one?

    Jim



     
  20. DOC BOLM

    DOC BOLM New Member

    Joined:
    Aug 21, 2008
    Messages:
    681
    Likes Received:
    0
    Just put tape on it ,6 1/2 "give or take 1/16". if i ever have to remove it i will have to cut and replace crank.
     

Share This Page