Big chainrings

Discussion in 'Spare Parts, Tools & Product Developement' started by Alaskavan, Nov 19, 2007.

  1. Alaskavan

    Alaskavan Guest

    I couldn't find where anyone had talked much about this subject, so: Has anyone tried huge chainrings? Like 62 - 65 tooth, so the engine can be human assisted in the 30+ mph range?
     

  2. noah

    noah Guest

    Hmmm...might work nicely
     
  3. Interesting idea....would probably work too...of course taking the lazy way out maybe we could mod the engine for more power...Oh yeah!.....I did see a story on a fella named Dr. Abbott I think years ago....had a 20" bike (well wheels at least)....and had this humongous (I think 140 tooth or so nut it has been years since I read about it) front chain ring and went something like 120 MPH or so with human power only on the flat...of course he did cheat a little and had a specially designed vehicle break the wind for him (he rode behind the vehicle in an enclosed area behind the vehicle).
     
  4. Alaskavan

    Alaskavan Guest

    I'm not truely concerned about how much power I will add to moving the trike. It's more of a thing of during my 50+ mile round trip commute, I might as well get some exercize. And if I'm going to pedal, I'd like to be able to keep up with the motor. But I think 140 tooth is a bit much.
     
  5. Peter

    Peter New Member

  6. Alaskavan

    Alaskavan Guest

    I bought and installed a 62 tooth. Unfortunately, I had to change my freewheel cassette to a 7-speed which has a 13 tooth high gear iinstead of the 11 tooth I had on the old 8-speed. Compromises. Oh well.
     
  7. Demosthenese

    Demosthenese Guest

    are you keeping up with the engine?
     
  8. Heck with your bike not needing a pedal assist when starting off as seen in your amazing video's then it would look so cool pedaling up a steep hill with that crazy gearing.
    But then again,it may be a real dawg in the event of a minor breakdown where you need to disconnect your chain so you can peddle on home.
    I say as long as you can keep up to 30 mph you should be okay.
     
  9. sparky

    sparky Active Member

    I'd really like to know what size front sprockets would be needed to assist a motor.

    My pedal gearing is at 36t in front & 16t in rear, and it sucks regardless of the engine being on or not. I went ahead and bought a new 44t crank but haven't installed it yet. I'd much rather wait for something between 50t & 60t crank. My local bicycle shop prolly lied when they said 44t was the biggest available.
     
  10. Alaskavan

    Alaskavan Guest

    I can pretty easily pedal up to about 25 mph in high gear. As for pedaling if the motor breaks, I've had a couple of electrical glitches (under control now). I've had to pedal home 7 miles over some pretty steep hills. My low gear is 27t on the front and 34t on the rear. With a 20" wheel. It can take a while to get up a hill, but it will get there.
     
  11. turbo/chaos

    turbo/chaos Guest

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