Shift Kit Question

Discussion in 'Motorized Bicycle General Discussion' started by twowheeledfox, Mar 30, 2010.

  1. twowheeledfox

    twowheeledfox New Member

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    I have selected a Giant full-suspension frame for my build. It has full suspension but with a mid-suspension link positioned high in the frame so there's plenty of space for the motor. If I get the jackshaft, will the suspension interfere with the chain and therefore create problems with tension etc?

    It's a Giant ATX 97.6 (thats what the frame sticker says) for reference.

    Thanks.
     
  2. Bikeguy Joe

    Bikeguy Joe Godfather of Motorized Bicycles

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    I'm going to bump this one up....
     
  3. BarelyAWake

    BarelyAWake New Member

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    If ya could post a coupla pics of yer bike it would help, is it like the yeller un in the attached pic?

    If so and the engine fits well (carb clearance comes to mind) then I don't think there'll be a problem. The shiftkit takes over your (unsuspended) crank sprockets so there isn't any slack caused by travel, the shiftkit itself is angled down quite a bit so I think you'll clear the shock & pivot easily. It's remotely possible that under full compression your rear tire might come close to the shiftkit's jackshaft... I really doubt it tho and that's something you could fix with spacers/shims/standoffs for the rear engine/shiftkit mount anyway.

    SBP has a pic of one with a slightly different rear suspension on their homepage: http://www.sickbikeparts.com/Images/FS-SBP.jpg


    Great bike for motorizing BTW, gonna be an ossum ride (^)
     

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    #3 BarelyAWake, Mar 31, 2010
    Last edited: Mar 31, 2010
  4. Maxvision

    Maxvision New Member

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    As long as the pedal crank assembly doesn't move seperate from the engine you shouldn't have a problem.
     
  5. twowheeledfox

    twowheeledfox New Member

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    Thanks- great to know it'll work, it's very similar to BarelyAwake's pic but with a round downtube and spoked wheels (those alloys look fantastic though; wish I had that model).

    Wanted to go full-suspension as part of a reliable, go anywhere type build, also have a springer seat and hydraulic RST fronts so it should be a smooth ride, and just got my headlights in the mail today dance1

    Will a bike sales shop remove the bottom bracket on these? It uses the kind that has a splined face so you need a crank removal tool, and there's a bike shop about >0.7 miles from my house.
     
  6. twowheeledfox

    twowheeledfox New Member

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    Question about the BB replacement: Why does the BB need to be replaced if the freewheel is on the crank? Is it ever possible to use the BB already on the bike? SBP members, it is the type 3 (sealed cartrige) with a good pedal clearance.

    PS- Just rode a friend's fully streeted shifter build today and it's brilliant. Even with a 3-speed it rides like a Cub and looks like a motorbike. Really looking forward to my build now :D
     
  7. twowheeledfox

    twowheeledfox New Member

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    Bump... need an answer, please. Anyone from SBP?
     
  8. Ghost0

    Ghost0 New Member

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    Sorry guys for not showing up sooner. We are busy as heck shipping stuff, all I can say is you guys rock!

    OK, the reason you need one of our spindles is that they are wider than the ones that you currently have on your bike. The extra clearance is needed for the chainring freewheel assembly and provides better chain clearance for the jackshaft chain. If you get the HD kit then it comes with a new wider cartridge bottom bracket. Hope that answers your questions.
     
  9. twowheeledfox

    twowheeledfox New Member

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    Thanks... may be going with an old Huffy 26er frame than- it's got good paint, measures compatible with the shifter kit and motor, and accepts the RST fronts easily... this Giant needs too much damn work to use it as a frame (strip, paint, adjust suspension, buy BB tool/get BB removed, get new BB cups and bearings, etc).

    From looking at the kit it appears to use three total chains, one from motor output to jackshaft input, one from jackshaft input to BB crank, and final drive from BB Crank to rear wheel/gearbox. Do these chains require more maintenance (adjustment, lubrication etc) than a typically used chain of similar size? Do I need to worry about adjustment consistently (since there seem to be three chains, the potential for error is greater).
     
  10. Ghost0

    Ghost0 New Member

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    Well any new chain will stretch a bit so adjustment is usually necessary for some break in period. Quality chains and regular chain maintenance is a good plan. The only chain you really need to keep an eye on is the one from the jackshaft to the chainrings. That one needs to be adjusted especially when new. If you read through the installation instructions it will give you a better idea what you will need to do.
     
  11. twowheeledfox

    twowheeledfox New Member

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    New question... the rear wheel I am using has a 27t lowest gear and a 14t highest gear. What kinds of speeds would this get me? I also have a wheel with a 28/11t setup but it needs maintenance so I'd rather use the first. A gear ratio calculator would be fine if you could tell me how to use it as well.

    Thanks
     
  12. Ghost0

    Ghost0 New Member

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    Well a 27-14 is not much of a spread, the 28-11 is better but a lot depends on your engine and riding terrain. If it is pretty flat where you are you should be fine with the 27-14 but if you have a lot of hills then I would probably either get the 9 tooth jackshaft sprocket or 48 tooth chainring if you want a lower gear. The 34-13 mega range are the hot set up with the Shift Kit in my opinion. The super low first gear is awesome for starting from a stop and you can climb a vertical wall if you wanted to.
     
  13. twowheeledfox

    twowheeledfox New Member

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    Thanks for the response, would the 27t be low enough for my to set off from a stop? I was able to do so on a 44t singlespeed two-stroke, wondering what the gear cassette equivalent would be to that.

    Also, What are the requirements for a derailer to be used with the kit?
     
  14. Ghost0

    Ghost0 New Member

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    The 27 would be like running a 56 tooth sprocket. Your 14 would be like running a 29.

    Pretty much any decent derailleur that is adjusted correctly with a decent chain will be fine.
     
  15. twowheeledfox

    twowheeledfox New Member

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    Everything should work out fairly well than. Thanks for your help, I'll post here again if problems arise.

    Also, it is a great kit- I was riding a friend's shifter build a couple days ago and it did feel alot like a motorcycle, and even looked like one with lights and mirrors on it.
     
  16. twowheeledfox

    twowheeledfox New Member

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    I had a new idea- is it feasible to use an internally-geared hub, flip the wheel to make the drive on the left side, and bolt a 44t sprocket on the hub's sprocket (or weld, though a bracket looks possible to me) and just use the standard motor-to-wheel setup without a jackshaft? No offense to your product Ghost, I like it alot having ridden a build already, but for an interim until I can afford the $150 for the kit it would be good.

    The only issue I see is gear reduction. The motor to 44t would be standard and therefore work, but would typical 3 to 5-speed internal gearing have a proper lo and hi ratio to work?

    Thanks, if this is feasible i'll be riding soon :D
     
  17. Ghost0

    Ghost0 New Member

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    If you flip the wheel then the threads for the hub will be backwards so if you apply any forward motion it will just unscrew itself.
     
  18. twowheeledfox

    twowheeledfox New Member

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    Hmm... any fix for that? This may sound ridiculous (don't have anything in front of me to test it on) but maybe the axle could be removed and the hub and sprocket flipped around that way? Or maybe getting rid of the freewheel, if these hubs have them... since it would be a motor-to-wheel drive there would be no pedal involvement...
     
  19. twowheeledfox

    twowheeledfox New Member

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    Okay firstly new question... if this crazy three-speed idea doesn't work out than will a 36T sprocket work out in a singlespeed setup? I have a 68.6cc (measured) slanthead with CNS carb and pullstart. Using double headgaskets and slighty smaller-threaded autolite plug to decrease compression a tiny bit so it starts easier with the pull. I don't mind flintstoning a bit when setting off but my ultimate need is a cruising (5000 rpm or less) speed of 35 mph. If the 36t will do this without being impossible to start/stop with it is a good alternative. Thanks for any help here.

    Second i am buying the hub (cheaply) tommorow; $25 for a near-new Nexus 3-speed. Looks like it will bolt to the 44t (and maybe even the 36t if this works out) with a little modding, chain alignment with the motor might be annoying but still running one chain is better than many. Also, in case I need pedals I have a spare 44t sprocket to bolt the the right (pedal) side and use as an ultra-low moped type gear for setting off if the clutch is fried, alternative to pushing if it breaks etc. If using the hub as a gearbox for the motor doesn't work that will be the pedal gearbox and the motor will be single-speed hopefully with a 36t.

    So close yet so far away...laff
     
  20. mapbike

    mapbike Active Member

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    wooo weee.............! have you settled on something yet...! Good luck with your build...!

    .shft.
     

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