Discussion in 'Photos & Bicycle Builds' started by FireBellyCycles, Feb 3, 2009.

  1. Preliminary pics of my latest build "RatRace". Rear wheel will be strong spoked w/ Sturmey Archer 8spd disc mount hub and Sturmey cranks for 8 spd hub. I'll be purchasing an engine drive sprocket from Andy @ king's. I'll run KMC Kool Chain both sides no tensioner. I'm going w/ the dual pull Brake lever. All w/ a nice vintage "patina"!

    Attached Files:

  2. Nice healthy looking motor mounts, I wouldn't have welded mine if it came with something like that. Those skinny tires will fly but I'd be scared to hit a pot hole with them at speed (and with 8 speeds it ought to hit some high speeds). Will that be 8 speeds hooked up to the engine or just pedal power? It has an old school racing feel, light as can be but just barely strong enough to hold together. I like any imaginative ideas so good job on the tank placement, is the idea to to get a lower center of gravity? Looks like fun for the courageous.
    Last edited by a moderator: Feb 4, 2009
  3. bikebum1975

    bikebum1975 Member

    Looks like a very fast ride indeed. Inventive way to mount the gas tank I like it just works.
    That bike I imagine would be killer with a SBP shift kit. But very sweet looking ride.
    One question though how exactly did you mount the tank?
  4. It's going to be 8 pedaled speeds and one very tall engine gear. I will be using heavy duty spokes on front and rear and I keep thinkin' some track rims or maybe ?.

    It Is built for speed. I'm starting out w/ an ets of 47.5mph @ 7000 rpm. Pedaling the 8 speed hub is going to get the rider going fast enough to smoothly engage the clutch and allow the rider to help the motor get up to speed after that. Truly pedal assist!
    It will not be ridden at speed on public roads.

    The tank is mounted via the aluminum frame clamp in front and an aluminum channel underneath.

    Thanks for the comments!
  5. echotraveler

    echotraveler Member

    great looking silver bike! i like it, makes me scared....are you planning on riding them tires with low presure to get a better grip?
  6. I'll definately play around w/ tire pressures as I do w/ any bike. But this is a fair weather/road bike. I won't be ridin' in the rain.
  7. unraw

    unraw Member

    nice motor mounts!
  8. wheelbender6

    wheelbender6 Well-Known Member

    The tank mount rocks. Should lower the center of gravity.
  9. Thanks! I'm into this bike; it should be up 'n' runnin' this weekend!
  10. New photos! It's Alive!

    Gotta get another gas cap 'cause this one leaks, but stuff works.

    I love the 8 spd hub you can shift to any gear at any time. As you have probably noticed the shifter is aside the throttle so as to necessitate the removal of hand from throttle. The motor is not driving the gears but I think I'll be gentle to it and shift it like a motorcycle.

    The chain tensioner works (it's a 15 min rough proto). I'm gonna make another out of thicker plate and mill a groove for tensioning. The rubber covered steal bands hold tight to the frame.

    I've built bikes w/ this brake lever but this is my 1st bike w/ one. They're Really Nice!

    I ended up making my own sprocket mounts and bored out the middle of the kit sprocket to clear the disc mount and straighten the chainline.

    Attached Files:

    Last edited: Feb 16, 2009
  11. I'm using a small skateboard wheel as a tensioner, it would work great on your tensioner set up. They have 2 high quality sealed bearings, have a larger diameter and are made of urethane so they absorb a little shock and clatter.
  12. katsi

    katsi New Member


    Odd placement of the tank but I kinda like it. :cool2:
  13. Ok so heres the "finished" product w/ beefier tensioner, nice straight chainlines, 8 speeds and finally a sealed gas tank; maybe ride it to work in the mornin'.
    I'm very happy w/ this build. The bike feels really solid; brakes feel plenty strong. Geared ets mid 30's right now. :1eye:

    Attached Files:

  14. Update. The Sturmey Archer 8 speed hub doesn't respond well to being motor driven on the disc mount. I'm guessing the clutches inside the hub don't respond well to the pulses of the motor. I've not sold any of these for m/b use and won't be! I'm very happy w/ their front hubs, though, and they did warranty my 8 speed so I'm very happy w/ Sturmey Archer o/a!
    Looks like I'll be mounting a disc mount cassette hub and derailer in the coming week!
  15. skyl4rk

    skyl4rk Guest

    Did the disk mount fail? Or did the internal gear not shift right due to vibration?
  16. The disc mount is plenty stout. It just stopped working properly; shifted but didn't work in gear (intermitantly) and became unadjustable. All w/in 15 mi or so. Quite honestly could've been a defective hub but I don't want to keep trying. So I'm selling the replacement on fleabay.

    This is a very nice hub for bicycling and lends itself fantastically to alternate gear ratios, just doesn't seem to like being motor driven.

    One of the main scopes of my company is to provide components and service that add to the reliability, safety, and comfort of motorbicycles. This didn't make a good 1st impression so I'll go back to what I know is reliable to finish this build and continue to research other alternatives in the future.
  17. SimpleSimon

    SimpleSimon Active Member

    I quite like that "mission statement", and would wish that far more businesses took such a customer friendly approach.

    I wish you every success.
  18. unraw

    unraw Member

    It looks pretty fast.