Bottom bracket advice

Discussion in 'Motorized Bicycle General Discussion' started by dtv5403, Jun 11, 2015.

  1. dtv5403

    dtv5403 New Member

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    I am thinking about ordering this bottom bracket kit, since it is the cheapest one I can find: www.bicycle-engines.com/3pc-Wide-Crank-Pedal-Kit-4S-CDS-3pcCRANK.html but I want to know what is the smallest chainring I can get that will fit it without modification, and where to buy one. Absolutely do not want the 44t chainring, I like my pedal gearing much lower than that. Please only comment if you have a useful answer.
     
  2. knightscape

    knightscape Member

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    That's the kit crank that is included with the huasheng 4 stroke kits, I have it on my bike and hate it. The ring is just swaged onto the cotter fitting and the ring itself is out of round. The flat on the spindle is too far outboard and required filing down additional flat section to slide it over for proper chainline. I have never seen anyone selling smaller rings for that set up. I'm actually going to be switching out mine for the SBP cartridge bottom bracket once they have them back in stock. They have a keyed spindle that you can put any ring down to like 28t on via a carrier. It will cost a little more, but it looks to be a better quality part.
     
  3. dtv5403

    dtv5403 New Member

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    Not really concerned much with the quality.
     
  4. knightscape

    knightscape Member

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    Yeah, then your only issue is chainring selection. I have not seen any other off the shelf options to replace that cottered chainring. You could probably take an old cottered crankset and cut off the crank arm leaving the cotter fitting as long as you can get one that will fit the spindle. Something like this:
    http://www.ebay.com/itm/Right-crank-arm-with-sprocket-cottered-32-teeth-5-1-4-dia-9-16-pedal-vintage-/321767088292

    Then some careful work with a cut-off wheel and grinder and you'd have a smaller ring on a cotter. The one I linked is just an example of what I'm thinking of, not sure of the diameter of the kit crank spindle, I can measure mine tonight if that would help you out.
     
  5. dtv5403

    dtv5403 New Member

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    My luck I'd probably screw it up. Maybe time to consider other options. Thank you for the advice though.
     
  6. culvercityclassic

    culvercityclassic Well-Known Member

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  7. dtv5403

    dtv5403 New Member

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    That would be perfect, where can I get a setup like that?
     
  8. knightscape

    knightscape Member

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    I'm making a whole series of assumptions here: I bet CCC is going to say he cut the stock ring then drilled and tapped that Bmx ring to mount- would involve a cutoff wheel or hacksaw, grinder, drilling and tapping.
     
  9. dtv5403

    dtv5403 New Member

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    I don't see there being enough space on the stock ring to drill it
     
  10. dtv5403

    dtv5403 New Member

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    Jeff, I want to apologize for those comments I made in the chat box the one day. I just hate dynos, no offense to you, I just think they are horribly ugly frames, not quite a regular cruiser and not quite a stretch, somewhere kind of in-betweenie. They are sort of tolerable to look at with a pair of K10's, but regular bicycle suspension forks look terrible on them, they look like a person with stick legs squatting. Sorry, that's just my opinion, no disrespect towards anyone here, everyone has different tastes, please don't take offense.
     
  11. dtv5403

    dtv5403 New Member

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    Got it figured now. Got a cheep azz Wally world mountain bike frame I use for a truing stand, it's got a 3spd chainring, lowest gear on it is 25t, gonna just cut the crank arm off, drill out the rivets that hold the gears, and pull off the 25t gear. First I'll see if it can press right on to the wide kit, if not I'll just drill holes in the 44t chain ring and bolt the 25t gear to the 44t chain ring
     
  12. dtv5403

    dtv5403 New Member

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    Well, it took some doing but I was able to get the 25t gear off the mountain bike. I started out taking my grinder and cutting the crank arm off at the spindle, opposite the gear cluster, thinking I could take a hammer and just knock the spindle out the other side and then drill the rivets out holding the gears together. Didn't work out that way, because the spindle wouldn't come out. So I cut the arm off the gear side, and drilled out the rivets holding the largest gear on. This gave me enough room to cut through the spindle, but the gears still weren't coming off. So I set about drilling out the rivets that held the smaller gears together, and when that was done I took another look at the spindle and realized I could see the square part of the spindle. So I took my grinder and turned it sideways and ground into the square part of the spindle. This relieved the pressure on the square taper and I knocked the gears off with a hammer. I then realized the gears had not only been riveted together, they were also splined to the crank arm. So I took my grinder and ground down the splines, then hit it with a hammer and the two smaller gears finally separated. Now I have a 25t gear that I can bolt onto the other chain ring after I hack it apart to fit.
     
    #12 dtv5403, Jun 17, 2015
    Last edited: Jun 26, 2015

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