A new Geared Experiment idea maybe?

Discussion in 'Performance Mods' started by cheap ride, Nov 11, 2007.

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  1. cheap ride

    cheap ride Guest

    Been reading on the forum of all the ways to gear our engines without to much cost, Here's my idea, Instead of puting the internal geared hub on the back wheel (logical place) why not locate it directly behind the output sprocket from the engine? then attach another sprocket very close to the sprocket on the geared hub, sitting together side by side, so output from engine to geared hub sprocket , then to neighbour sprocket, then directly back to our standard spoke mounted rear wheel sprocket. That's it , Is that great or what? , No jack shaft to stuff with, complete left side geared drive.

    One small problem that i'm sure we can overcome quite easily, The sprocket teeth on the geared hub sprocket are obviously for bicycle chains, change this one sprocket to a sprocket with our 415 tooth spacing and that's it.:smile:

    Also would a cheap Sturmey Archer 3 speed Internal geared hub for $52 U.S. do the job? I think they give a %133 total ratio change.We can always manipulate gearing outcome by using different size rear sprockets and hub sprockets. :smile: comments please.

  2. 5-7HEAVEN

    5-7HEAVEN Guest

    :cool: The first hurdle is the fact that the internal gear hub is built for right-side drive and left-side coaster-brake.

    If you were to affix a left-side sprocket on the hub, you would not be able to take advantage of the internal gears. If you reversed the hub, the sprocket would not spin CCW. It would lock up, because of the coaster brake in the hub.

    In essence, the hub you mount behind the engine sprocket becomes the jackshaft. using two sprockets means that the engine needs to shift outwards on the left-side, to align the inside sprocket with the rear sprocket.

    ORR, align the engine with the inside sprocket and use OCC STINGRAY sprocket adaptor to move the driven sprocket slightly outward.

    I am doubtful if this arrangement would work the way you described. However, keep thinking. you might be on a good track.

    It is a good theory, and if it worked, it'd be like happy time engine with a 48-tooth sprocket and a 36-tooth sprocket. that computes to great low end gearing AND awesome high-end ratio.

    Last edited by a moderator: Nov 11, 2007
  3. Hmmmmm,,,,I think that mounting the hub backwards (so that the sprocket of the Sturmey is in line with the engine sprocket will NOT work because at that point tie Sturmey will be freewheeling....There was and old Sturmey that was a FIXED multispeed hub that would solve the freewheeling issue but they are no longer made...modding a new Sturmey can be done but requires disassembly and machine work / possible fabbing (see Sheldon Brown's site I think they have a link or article on making the hub FIXED...i.e. non freewheeling)...

    As far as 2 sprockets side by side on the same hub shaft...I am not sure that that would apply the multispeed capability of the hub into the drive train to be applied to the rear sprocket....The other sprocket would probably have to be fixed to the hub shell itself for this to happen ( I think this is what you meant though...the 2 sprockets just cant be mounted to the SAME shaft)....At this point, the other concern I could think of might be chain angles and the chain clearing the rear tire.....That is because if you align the drive sprocket of the Sturmey perfectly the the output of the engine, the fact that the other sprocket on the has to be mounted to the hub itself for the hubs gearing to be useable
    the chain at that point may be too far inboard when making a straight line to the rear tire for the chain to clear?...offsetting the hub to the left (while seated on the bike) may help with alignment issues but if using a happy time or similar engine the concern would be to not have the chain rub the inside of engine sprocket cover....of course that could be modded to if needed.....Hard to say about chainline issues without actually trial fitting to a bike or your particular bike....

    Sprocket would not be a problem to make (see list of supporting sponsors ;-)....)

    Hub mount would have to be custom fabbed.....

    I believe the idea sounds like it should work (unless I misses something too) BUT would require a fair amount of modding....

    By all means try it and keep us all posted....I am not 100% sure if there is anybody here running a multi speed setup yet.....It would be neat to be possibly the first huh?


  4. Oh...because of 5-7Heaven's post be sure to get the non coaster brake model....I didn't think of that earlier....That could have been another possible problem ;-)

  5. Hmmmm....wow brain is burning now....if you try to drive the right side under engine power
    you WILL need to make sure to have the human powered portion on its own freewheeling system of some sort so your pedals won't spin while under engine power (you could check out Staton's Site on how they use a Right side drive for engine powered applications while having the rider able to pedal or freewheel.. It is a simple little adaptor piece they make/sell)...but anyways that assumes you wanted right hand drive....

    Wow....I like this multispeed stuff but gotta eat before I pass out!...

    I like the simplicity of the original idea although it still does require alot of work !

    Either way go for it cause tinkering is half the fun.....BUT the real fun starts if it works!

  6. minibiker

    minibiker Guest

    if any ne 1 made a left side geared hub with a peddle optoin they would make a bank!!!
  7. Ghost0

    Ghost0 Guest

    Funny you should ask about the left side geared hub option. My dad and I are in the process of designing that very item. We should have prototypes by the beginning of the year. We may even ask of few of the members to try out a few of the prototypes to get some feedback. I will keep all up to date as the project progresses.
  8. 5-7HEAVEN

    5-7HEAVEN Guest

    :cool:STATON makes a 16t left-side freewheel sprocket, to be used with their HD hub. To utilize this driven gear, one would reverse the chainwheel and swap in/modify a 32-tooth crankset sprocket to maintain 1:2 cruiser bike gear ratio.

    Gears are turning in my head. I have another theory to explore in "geared experiments.":rolleyes:

  9. iRide Customs

    iRide Customs Member

    I've done this and it works but you have to have a freewheel hub for the jack shaft. If you had that you'd need a pull start on you engine. I'm not sure how long the internals of the hub would hold up to the forces of the motor. I used a Shimano on this bike. Sturmey Archer makes a very inexpensive 3 speed freewheel hub...I think it's about $60 with a shifter. If you use a disc compatible rear hub you could just bolt a 44t where the rotor would be bolted on. I've done that too and it works great!


    Attached Files:

    Last edited: Nov 11, 2007
  10. cheap ride

    cheap ride Guest

    Thankyou all

    Wow, what a great bunch of knowledgable people, i'm so glad i found this forum, so many people, willing to devote thier experience and knowledge in helping others with likeminded interests, love that chopper dan, superb craftsmanship,quite artistic, and that seat, simple, buitifully crafted.

    Now you have further inspired me to venture back to my shed and try to create what you guys have done so well. thankyou all for your advice and input. adrian, Perth, Western Australia. incidentally it was 39.8 degrees celcius yesterday, a tad to hot for the shed.:grin:
  11. Some ideas from GT bike

    Frame mounted hub:
    Check the GT dowhill bike frame mounted internal hub set up. One comment on this set up is that the hub is not touching the frame on the encased tubular section around it. That is done just for looks. The hub is suspended from the axel. The output sprocket from the hub is mounted where the disc would go, on the left side.

    In our case with an engine with an output sprocket on the left side, we would have to mount the Staton double gear sprocket on the right side of the hub. The engine would still need a jack shaft to bring the power to the right side and work on some ratio reduction.
    But the pedals would just fit exactly like on the GT.
    An ideal candidate for the hub would be the either the dual drive hub(3gears 187% change) from Sram. It would require a fixgear/bmx adaptor(acepts BMX style feewheels) from Sheldon Brown's web page: http://sheldonbrown.com/harris/fixed-hubs.html
    Another one to check would be the new Sram i-motion9-disc(to mount the output sprocket instead of the disc) (9gears 340% change) (for sale next year).
    Not cheap, not that complicated, but still needs a jackshaft and enough room on the frame for al this to work
    GT internal hub on frame right side view.jpg

    GT internal hub on frame left side view.jpg

    GT internal hub on frame bike.jpg

    Staton freewheel and fixed sprocket for left side.jpg

    fixedk7(From Sheldon Browns page).jpg
    Last edited by a moderator: Nov 21, 2007
  12. Maybe I did not explain the above good enough. The idea is to have only one chain from the frame to the wheel. All the double chains and sprockets and the internal hub and engine work on the frame.

    This set up is clean an opens the door for REAR SUSPENSION.

    A big issue when off-road riding.
    You can't have rear suspension with frame mounted engine and the double chain to the wheel set up currently in use.
    So this might be it, to hit some dirt roads with the benefit of full rear suspension and gears.
    Last edited by a moderator: Nov 21, 2007
  13. mickey

    mickey Guest

    That is one cool system. I hope that Ghost0 sees this post, something like this would be perfect for his custom offroad bike.
  14. hlombard

    hlombard New Member

    Internal gear jacshaft

    Great bike!

    Why do you flip the hub? Isn't the sprocket usually on the right side? Or is the photo flipped? I've never touched one of these hubs - do they freewheel? If they do, and you flip them, wouldn' they freewheel when you pedal?

  15. quarkdude

    quarkdude Guest

    Product tester

    Hello Ghost,
    If you would like a bike to try it on, mine is available, I would be honored to test a left side geared hub. I can provide detailed feedback to the site with pictures and video.
    ....Thanks, quarkdude:grin:
  16. Ghost0

    Ghost0 Guest

  17. quarkdude

    quarkdude Guest

    Product tester

    Hello Ghost,

    I looked at the thread link you provided and looked at the pictures, Wow! I like it a lot. When you get it to the level you like it, I am ready to start wrenching on my bike and installing the product for testing and Video feedback.:grin::grin::grin: Let me know when you are ready, I'm ready now. That is soo cool what you guys have come up with.
    ........Thanks a bunch, quarkdude
  18. alexander

    alexander Member

    10.000km done with 3 speed gearbox/hub

    see my new thread in 'introduce yourself' on 3 speed gearbox/hub
  19. fetor56

    fetor56 Guest

    Closer pics & detailed explanation & you'll be my new Hero. :)
  20. duivendyk

    duivendyk Guest

    It still takes an overall reduction of 15-20 (depending on engine size) to the rear wheel.The SA hub is 075-1-1.33.So two 4:1 chain reductions would be reqd.I don't know what the smallest sprocket is that can be mounted on the hub body prob 20t +..Also the input sprocket on the hub would have to be substantal.It could work in principle with an internal 4:1 reduction in the engine, if the engine output was on the right side.The hub would be running much faster than normal although at reduced torque, the gears might wear more,the old SA hubs I am familiar with needed oil,mainly for the gears.