1. Photobucket recently update their Terms of Use and are now requiring a $399/year membership fee in order to share the photos that you host with them on other websites. If you use Photobucket to host your photos and are using a FREE account, none of your photos will show up on other websites. Please upload your photos directly to the forum here and no longer use Photobucket. Click here to follow the discussion topic...
    Dismiss Notice
  2. There is a solution for the broken Photobucket image issue on forums. If you use Firefox or Chrome, go into the Extensions (Chrome) or Add-Ons (Firefox) and search for "Photobucket Embed Fix" - it will have an icon that looks like a green piece from a jigsaw puzzle. Install the extension/add-on, restart your browser (Chrome) and you should be able to see all of the Photbucket images again.
    Dismiss Notice

Gears???

Discussion in 'HOW TO' started by BikeBuilders, Jan 10, 2012.

  1. BikeBuilders

    BikeBuilders

    Joined:
    Jan 9, 2012
    Messages:
    50
    Location:
    Orlando, Fl
    Just a little curious about something here.... I have done a lot of reading, and a lot of lurking here.... You guys do some amazing stuff. And I love the fact that building bicycles is a WHOLE LOT cheaper than building motorcycles. Perfect hobby for me.....

    What I have seen is that some of these custom built bikes can end up being pretty darn heavy. Not so much the bikes here that I have seen, but on another site. Chopper bikes with big back tires to be exact. I like that style.

    So, onto my question.... With all of the amazing things I have seen you guys do, why is it that all of the bikes I have seen remain single speed? Seems like it would be easy enough to at least add a rear derailer. This would give you at least a few gears. Even if you left the front a single sprocket only. I am sure there is a logical reason, just wondering what it is before I head down a road doomed for failure.

    So what's the reason? Mechanically unadvisable, personal preference, oversight on my part????

    Thanks
    Rob
     
  2. cman

    cman Moderator

    Joined:
    Dec 4, 2006
    Messages:
    11,010
    Location:
    Boise,ID
    Most like the simple style of a single speed coaster brake. No cables for brakes or gears.

    3 speed internal geared hubs are popular or 2 speed kickback hubs.
     
  3. BikeBuilders

    BikeBuilders

    Joined:
    Jan 9, 2012
    Messages:
    50
    Location:
    Orlando, Fl
    That makes sense.... A cleaner look. But in the event I wanted to use a rear hub from say a 21 speed mountain bike, and the rear derailer (and possibly even front), there is no mechanical or other unforeseen reason it wouldn't work???? Or any experienced builder warnings, tips or tricks I should know about?
     
  4. jalopyjimmy13

    jalopyjimmy13

    Joined:
    Oct 1, 2011
    Messages:
    829
    Location:
    BELVIDERE ILLINOIS 61008
    cable length :idea:
     
  5. BikeBuilders

    BikeBuilders

    Joined:
    Jan 9, 2012
    Messages:
    50
    Location:
    Orlando, Fl
    Understood.... Any other words of wisdom, warnings or tips???
     
  6. udallcustombikes

    udallcustombikes Moderator

    Joined:
    Aug 20, 2009
    Messages:
    4,567
    Location:
    Derby, KS
    I built my Monster Trike using an 18 speed gearing to spin the 31" Coopers.
    [​IMG]

    One problem you may encounter with a wider rear tire is your chain line. If it is an issue you can employ a jackshaft compensate.
     
  7. Dr. Tankenstein

    Dr. Tankenstein

    Joined:
    May 20, 2009
    Messages:
    5,723
    Location:
    Marietta, GA
    Another thing to consider is the chain pitch. You have to switch your front sprocket from 1/2 x 1/8" pitch to 1/2 x 3/32" in order for smooth/proper operation.

    Good luck!

    Cheers,
    Dr. T
     
  8. BikeBuilders

    BikeBuilders

    Joined:
    Jan 9, 2012
    Messages:
    50
    Location:
    Orlando, Fl
    Forgive the newbie question, but what is "chain pitch"??? Please explain....
     
  9. kingfish254

    kingfish254 CHECK OUT MY SALE THREAD FOR COOL STUFF! Pro Member

    Joined:
    Aug 31, 2009
    Messages:
    25,113
    Location:
    Historic Savannah
    Chain pitch is the distance between chain rivets. Almost all modern chains are 1/2 pitch.

    The 1/8 and 3/32 that Tank refers to is the Chain Width (between two inner plates). Single speed and three speed chains are typically 1/8. Deraileur bikes are typically 3/32.
     
  10. wheelymarko

    wheelymarko

    Joined:
    Dec 15, 2011
    Messages:
    288
    Location:
    Mtn Home Ar.
    I like simplicity! Mine is a coaster brake triplespeed. :roll:
     
  11. wimpy

    wimpy

    Joined:
    Sep 22, 2009
    Messages:
    553
    Location:
    The Netherlands (Westcoast)
    Mine too. And I used an 80 mm backrim (not wider),so I didn't have to alter the standard sprockets into off-set sprockets,because of the chain clearance. Any other wide(r) rim brings along the problem of how get the chain from front to back,in a straight line. So I chose the easy way.
     
  12. DGuff

    DGuff

    Joined:
    Mar 24, 2010
    Messages:
    49
    Location:
    Richmond Tx
    Another thing to look at is the spacing of the hub itself. Most coatser hubs have a 118mm to 120mm spacing so the frame is built to match. A 6 spd or greater hubs spacing starts at around 125mm and go up to 135mm so you would have to spread the rear chainstays to make it work. Not a real big deal until but something to look at.
     
  13. BikeBuilders

    BikeBuilders

    Joined:
    Jan 9, 2012
    Messages:
    50
    Location:
    Orlando, Fl
    Gotcha.... But if I use all the components (rear hub and sprocket, front spocket and chain) from the same donor bike, I won"t have to worry about changing anything, right??
     
  14. Dr. Tankenstein

    Dr. Tankenstein

    Joined:
    May 20, 2009
    Messages:
    5,723
    Location:
    Marietta, GA
    Yep, that'll work. Just be aware, most older and newer, single speed bikes use a one piece crankset, like this;
    [​IMG]

    Now, if you can find a donor with a multi-speed rear, one piece crankset front, you're good to go.

    However, if the donor has a three piece crankset (which most modern mountain bikes, BMX bikes, etc...use), like this:
    [​IMG]

    You'll need to get a US-euro conversion kit, like this:
    [​IMG]
    http://www.amazon.com/BB-Conversion-Bp-American-To-Euro/dp/B001G8TSPS

    Good luck, keep asking questions, there's a LOT of knowledgeable people on here! :wink:

    Cheers,
    Dr. T
     
  15. BikeBuilders

    BikeBuilders

    Joined:
    Jan 9, 2012
    Messages:
    50
    Location:
    Orlando, Fl
    Thanks, but now I am confused.... If all parts come from the same donor bike, why would I need a us/euro conversion? Seems like all I would need to do would be lengthen the chain if necessary.
     
  16. wheelymarko

    wheelymarko

    Joined:
    Dec 15, 2011
    Messages:
    288
    Location:
    Mtn Home Ar.
    The conversion is just another way of doing it :)
     
  17. Dr. Tankenstein

    Dr. Tankenstein

    Joined:
    May 20, 2009
    Messages:
    5,723
    Location:
    Marietta, GA
    Sorry, I just re-read that, it was a little confusing, even to me.. :roll:
    Basically, it all depends on the frame you using for your bike (not the donor).

    Typically, newer frames that utilize a 3-piece crank with multi-speed rear hubs have a smaller bottom bracket tube compared to the 'classic' single speed frames.

    Now, if you can find a vintage '5 speed' donor bike with a single front sprocket, a 1-piece crank and a multi-speed rear, then everything should move over to the 'final' frame with no problem.

    If you find a 'modern' donor, like a mountain bike, with a 3-piece crank (the number of sprockets is irrelevant) and a multi-speed rear, chances are you'll need the bottom bracket adapter. The adapter reduces the internal size of the bottom bracket tube down from a 1-piece size to the modern (or euro) 3-piece size.

    Hope that makes more sense.. :D

    Cheers,
    Dr. T
     
  18. meatwad1

    meatwad1

    Joined:
    Jan 14, 2008
    Messages:
    89
    Hmmm... How do I explain this where someone who has done such a thing will not try to argue with me on their reason for doing so? This will be a challenge.

    If a bicycle is so unergomatic , so heavy and so inefficent that its top speed is only slightly more than a crawl then having multiple gears on it is redundant. Finding a comfortable gear ratio for such a bike I imagine is a very specific task. Having multiple gears on one is pointless.
     
  19. gcrank1

    gcrank1

    Joined:
    Nov 17, 2011
    Messages:
    1,204
    Location:
    North of Madison, Wisconsin, USA
    It is the nature of man to find a complicated solution to a simple (or, as some would argue, a non-existent) problem......... :wink:
     
  20. meatwad1

    meatwad1

    Joined:
    Jan 14, 2008
    Messages:
    89
    Sure is. Thankfully when I have done so I can pass it off as artistic license. Thank God for Rat rod bikes :)
     

Share This Page