1. Holyman92

    Holyman92 New Member

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    So I was wondering, has anyone tried to use a 3 speed hub with a 2 stroke engine? These engines seem like they can put out both torque and speed depending on the hearing and with my new bullet train and stock sprocket (42 tooth I think) I'm able to go up really steep inclines doing 20mph with 20" tires... I was just wondering if I was to add a 3 speed hub and a Jack shaft if I would be able to get the best of both worlds and get speed when I need it and torque for the hills where I live....
     
  2. JackieJak

    JackieJak New Member

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  3. StevenMain

    StevenMain New Member

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    use a 5 speed hub RX RK5 is what I used, so much better in ratio spread. Also pretty freaking bulletproof so far.

    [​IMG]
     
  4. wrenching4fun

    wrenching4fun Member

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    Here are some shots of my HT hooked up to a Shimano Nexus 3-speed through a SBP jackshaft. It's controlled with a vintage frame mounted indexed shifter. I started out with a Huasheng 4-stroker that pooped out on me after 4 yeas of riding. Had the HT sitting on a shelf and decided for something different. Had to remove mounting plate and adapt jackshaft mount to work with the rear mount of the 66cc HT, but it works great. The Shimano hub is pretty strong, but it doesn't have sealed bearings. If you ride in water the bearings will rust and she fails. Internals are cheap to replace, about $100. I like the extra power of the larger engine and its fun to shift through the gears. It's easy to change gearing. I have one secondary drive gear for road use and another for trail riding. The 3-speed comes with a coaster brake setup or a disc brakes. I recommend the disc setup with Avid BB7 MTB calipers and 220 mm discs. I can smoke my tires with a dual brake lever to allow for a clutch lever on the left handlebar. Some will say this is no longer a MB, but a small motorcycle. I don't care what you call it, it's fun as heck to ride. StevenMain has a good point about close ratios, but I have plenty of low end and top end with this hub. Good luck on your build. Remember, this is all about fun.
     

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  5. djnutz

    djnutz New Member

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    One of the biggest reasons internally geared hubs fail on motor assisted bicycles is due to how they are used. Many internally geared hubs don't like to be shifted while peddling. I am a bicycle mechanic and I have rebuilt my fair share of internally geared hubs. Shimano and Sturmey Archer hubs can be damaged if they are shifted while the pedals are turning, even if there is no load. With a shift kit installed, even though the pedals are attached to a freewheel bearing and remain in the same position, the bottom bracket and the drive chain going to the internally geared hub could still be spinning.

    I burned through a half dozen internally geared hubs before I found the SRAM G8. It can be shifted while the drive chain is spinning, but like any bicycle shifting, it should be shifted when not under a load. For my bike, I just let off the throttle, shift, then back on the throttle.

    I have the disc brake version of the G8 and it has been a very solid hub.

    All this said, SRAM has discontinued all production of internally geared hubs as of FEB of this year. That means parts are going to be hard to come by in the future. But, if you can get one off Ebay or Craigslist, I highly recommend the SRAM G8 disc hub.
     

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