3 speed speedster

Discussion in 'General Questions' started by RATRODER, Jun 27, 2008.

  1. RATRODER

    RATRODER Guest

    A project I've been thinking about for some time,now that got off my lazy b**t. It is a 70cc ht run to a 22t sprocket jack shaft,then a 10t to a 22t on the hub. It needs a lot of work yet,but so far so good.Yes I know no peddles. louis
     

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  2. srdavo

    srdavo Active Member

    that is "from the ground up" awesome!!

    very cool!
    have you ridden it yet?
    have you run it thru the gears?

    I like it.:D
     
    Last edited: Jun 27, 2008
  3. duivendyk

    duivendyk Guest

    a 3 speed hub?,how do you get started with no pedals?
     
  4. RATRODER

    RATRODER Guest

    Yes and Yes, 1st gear is about 75%input,2nd gear 1-1,3rd is133%input. It pulls the hills real good. louis
     
  5. RATRODER

    RATRODER Guest

    It has a Boygofast pull start. louis
     
  6. JemmaUK

    JemmaUK Guest

    I like the style of it :)

    What is the top speed with that setup?

    More to the point where did you get the jackshaft from?

    That would be perfect for what I have in mind which would be using a 7 speed shimano hub with a tankside shift lever and the pull start on a 48cc

    Bonus is that it would fit my current Schwinn cruiser and give me a 7 speed MB :)

    Jemma xx
     
  7. the sturmey 3-speed is bomb proof and shimono and sram are getting better but I would advise staying away from the 5+ speed hubs because to say it basically the more gears you stack in the hub the thinner you have to make them and the weeker they are
     
  8. sparky

    sparky Active Member

    I was going to keep a folding bike by a brand called DownTube that came with an 8spd Sturmey, but I read some stuff about hubs with 5~7+ gears requiring professional help taking it apart & reassembling, which didn't sound any good. The stepping between gears was also pretty random... some gears that were right next to each other felt like they were the same ratio, and then the next would provide a much bigger difference. I'm sure I coulda gotten used to just using 4 or 5 of the 8 gears, but it just feels too awkward with that uneven stepping.
     
  9. duivendyk

    duivendyk Guest

    The SA was sturdy but not indestructable as I had occasion to find out on the Isle of Mull in Scotland. Very inconvenient being stuck in the wrong gear.If you keep them well oiled and never ever change gears under load they are quite durable though.
     
  10. duivendyk

    duivendyk Guest

    This is odd acording to the Sheldon Brown website the 8 sp S&A hub has a 28% change between 1st/2nd and 7/8th gear, the others are all around 13%. www,sheldonbrown.com
    Maybe there was something amiss with your hub.I agree you don't need that many steps,as long as the total range is adequate,they were prob. trying to compete with 7 speed derailer hubs.
    The 4 speed Shimano Nexus hub had around a 2.5 ratio which is plenty.I don't know if you can service them without special tools,The 8 speeds,forget it.The old 3 speed Shimano hubs were not all that hard to work on,I recall.I liked their construction better than the S&A 3 speeds (no failure prone little chain coming out of it, but a sturdy bellcrank actuator.
     
  11. sparky

    sparky Active Member

    28% to 13% or whatever then back to 28% was a pretty awkward jump for me, tho. The crank was missing some piece too, and I decided to go with the bike that already had the motor on it. The DownTube was certainly a much better bike, tho.... it's just that I was really buying the bike for the 8spd hub, and afterward I found out if something DID happen, I wouldn't be able to fix it myself. That was it for me. I know you can't shift under load, but I'm personally not a fan of seamlessly shifting derailers while I'm pedaling, much less completely stopping for internal gears. BMXs and NuVinci are my cuppa tea.
     
  12. duivendyk

    duivendyk Guest

    It does appear rather extreme, over a two to one difference in step size.Other manufacturers of these type of hubs like Shimano do a lot better in this regard.These hubs are all monsters of complexity,comparable to a tiny automatic transmission.The NV looks like a marvel of simplicity and should not be all that expensive to manufacture, really,but that does not get to be reflected in the price it seems.
     
  13. RATRODER

    RATRODER Guest

    I'm personally not a fan of seamlessly shifting derailers while I'm pedaling, much less completely stopping for internal gears.

    sparky you don't have to stop to shift, I just let off the gas and shift (up&down) louis
     
  14. sparky

    sparky Active Member

    That's what I meant... stop pedaling or gassing. I've always liked BMXs best because there's no jerking, no derailer to adjust, and just constant power to the wheels. NuVinci is the same way, but with the ability to change gear ratios -- SUH-WEET!!

    Like I said, there's still a loss of power even with derailers where you don't need to stop, and there will be even more loss of power when you totally stop pedaling (or gassing) for that one second. I'm a little nitpicky sometimes, and this is one of those times. Tho, I would definitely scoop up an internally geared hub with 3 to 5 gears if it was cheap... just to mess around with, since I can repair it myself (can't do that with an 8spd hub).
     
  15. davidsis

    davidsis Guest

    How fast will it go???????????????
     
  16. sparky

    sparky Active Member

    My point still stands that the SA 8spd hub has funky stepping between gears, is nearly impossible to work on for the average joe, and loses power when you let off to change gears.
     
    Last edited by a moderator: Jul 9, 2008
  17. duivendyk

    duivendyk Guest

    If you want to get up to speed on internally gearedhubs go to www.sheldonbrown.com .All sorts of info on these devices.It appears that the Shimano hubs (4,7and 8 speed) are not all that hard to take apart afterall,it's fairly straightforward to take the guts out in toto,putting them back together again might be another matter.Looking at my old Shimano hub I have concluded that it may well be possible to put dual sprockets on these things after all,it involves welding two of these dished input sprockets back to back together at their periphery,this creates adequate axial space between them for both chains.The trick is to mount this assemblage on the hub.To that end an annular ring of material has to be removed from the outside sprocket to make it possible for the for the locking snap ring to be installed.I think it is doable.These sprockets come in various sizes up to 22 t.In this manner you could retain pedaling ability(to keep the cops off your back),but also have a decent multi gear capability.
     
  18. TwoWalks

    TwoWalks Member

    As usual, I really like the frame. One you built that I drool over all the time is "Evans" racer. Do you build your own frames from scratch or alter existing frames? I would love to build my own frame but I would not trust my enemies arse on a frame I welded let alone my Arse.
     
  19. RATRODER

    RATRODER Guest

    TwoWalks yes I do build from scratch. I was never satisfied with the cruiser frames,(they do build nice bikes,but not my thing)
    I'm building a road bike,(existing frame) that has the right look to it.louis
     
  20. TwoWalks

    TwoWalks Member

    The frames you have built for the Board Track racers are fantastic. Great job. As stated above, I am in love with the "Evans" bike, my future dream. Guess I am going to have to figure out "how" or "where" to build a frame similar to that.
     
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