Chain ring upgrade-- Is it safe?

Discussion in 'Motorized Bicycle General Discussion' started by nubikeshop, Sep 14, 2009.

  1. nubikeshop

    nubikeshop New Member

    Joined:
    Aug 23, 2009
    Messages:
    5
    Likes Received:
    0
    Hey all. A build of mine has a 68.5cc with a 44 tooth rear chain ring. Gets above 30 easily, max of 39 downhill. I was curious if it would be safe to upgrade to a 36 or lower tooth chain ring. It would be cool to get some extra speed out of this thing, but would I be seriously compromising safety, structural integrity, ability to start easily, etc...?

    Thanks everyone
     
  2. azbill

    azbill Active Member

    Joined:
    May 18, 2008
    Messages:
    3,367
    Likes Received:
    0
    a 36 will give more top-end at the cost of bottom
    ie...more speed but less torque
    hills will be harder and so will launch
    your rpms will be lower for same cruising speed = longer engine life
    hope that helped :)
     
  3. Venice Motor Bikes

    Venice Motor Bikes Custom Builder / Dealer/Los Angeles

    Joined:
    Mar 20, 2008
    Messages:
    6,169
    Likes Received:
    18
    I'm kinda thinking that 40T sprockets are a better way to go these days... :D
     
  4. Retmachinist

    Retmachinist New Member

    Joined:
    Oct 21, 2008
    Messages:
    637
    Likes Received:
    0
    I would say it all depends on how safe you think your bicycle is at 40 m.p.h. Most of these bikes weren't made for that for any extended period of time.
    Myself, I only use the best components and some very good tires, and still don't care to go 40.m.p.h.
    That is strictly my opinion!

    John
     
  5. turtle tedd

    turtle tedd Member

    Joined:
    Jul 18, 2009
    Messages:
    153
    Likes Received:
    0
    40mph ..safe..no..a bicycle is not a motorcycle....I also use the best moving parts and the best tires..I think 30mph is pushing your luck
     
  6. azbill

    azbill Active Member

    Joined:
    May 18, 2008
    Messages:
    3,367
    Likes Received:
    0
    BTW...my last 2stroke had a 40tooth and I put 4000 miles on it (some KILLER hills here too !)
     
  7. azbill

    azbill Active Member

    Joined:
    May 18, 2008
    Messages:
    3,367
    Likes Received:
    0
    do you pedal a lot now ?
    when I did mt lemon, I was on the deviate and was using a 48,,,never pedalled once
    but, on the jag I pulled the trailer all over the hills here with a 40
     

Share This Page