Help with single speed

M.ister W
M.ister W Posts: 4
edited June 2008 in Road general
I'm a newbie to the forum but have been told that you're a helpful bunch so.......

My commuting bike is a single-speed, converted from an old road bike and still with a 6-speed cassette, one of the old screw on Shimano freewheels. Unfortunately my gear of choice means that the chain line isn't very straight so the chain sometimes jumps up a cog which pulls the chain tight and pulls the wheel forward, jamming it against the frame. I can't get the chain line any straighter with the current set up so I'm thinking of changing the 6-speed freewheel for a single speed one. Can anyone tell me what I need to buy? Can I fit a bmx freewheel or do I need a different one?

Thanks :)


  • peejay78
    peejay78 Posts: 3,378
    a new rear wheel would be your best bet.
  • Big Red S
    Big Red S Posts: 26,890
    A normal BMX freewheel will fit. Avoid anything micro drive.

    Depending on what your gear of choice is, it might not do anything for your chainline. Armed with a few different-sized axle spacers, it's normally possible to move the hub body along the axle until it's inline. Might need to redish the wheel if there's not a huge amount of space between the stays, though.
  • LeighB
    LeighB Posts: 326
    I converted a wheel like yours to single speed; mine is fixed with a track sprocket. I found that if you swap the large spacer on the wheel spindle from the freewheel side to the non drive side this puts the sprocket into a better position; you can then fine tune it with washers to get the chain line perfect. I have read various formulas for working out the chain line but I found looking from the back of the bike to see if it was straight worked fine. When the chain was lined up I moved the wheel rim back into alignment by loosening the spokes on one side and tightening them up on the other- re-dishing.
  • Hi

    I used a spacer kit with one cog.

    played around with the spacers to get the right chainline ... otostream/

    hope this helps