Advertisement
If you have a new account but are having problems posting or verifying your account, please email us on hello@boards.ie for help. Thanks :)
Hello all! Please ensure that you are posting a new thread or question in the appropriate forum. The Feedback forum is overwhelmed with questions that are having to be moved elsewhere. If you need help to verify your account contact hello@boards.ie
Hi there,
There is an issue with role permissions that is being worked on at the moment.
If you are having trouble with access or permissions on regional forums please post here to get access: https://www.boards.ie/discussion/2058365403/you-do-not-have-permission-for-that#latest

Single Speed: Chain Line

  • 19-10-2007 2:08pm
    #1
    Raam
    Registered Users, Registered Users 2 Posts: 14,318 ✭✭✭✭


    While cleaning my SS last night, I looked at the chain line and I can see that that the front chain ring and rear chain ring aren't totally in the same plane. In other words, the chain isn't totally straight. Is this wrong? Should I try to get the chain line dead straight? If so, do I need to start messing about with spacers, or should it be possible to make some minor adjustments to straighten it?


Comments

  • #2
    rp
    Users Awaiting Email Confirmation Posts: 1,227 ✭✭✭rp


    King Raam wrote: »
    While cleaning my SS last night, I looked at the chain line and I can see that that the front chain ring and rear chain ring aren't totally in the same plane. In other words, the chain isn't totally straight. Is this wrong? Should I try to get the chain line dead straight? If so, do I need to start messing about with spacers, or should it be possible to make some minor adjustments to straighten it?
    They should line up, for the sake of efficiency if nothing else.
    What size BB / rear fork (OLN) do you have? A std BB will put the middle (or single) chainring 50mm out, while a 120mm OLN rear-fork wants it to be 42.5mm IIRC - you can get some spacers to move the ring in a bit, and you might need longer chainring screws


  • #3
    Raam
    Registered Users, Registered Users 2 Posts: 14,318 ✭✭✭✭Raam


    I thought I posted a reply to this yesterday, weird. Anyway, here is what I thought I said...

    Rear fork is 120mm, BB is 70mm


  • #4
    Itsfixed
    Registered Users, Registered Users 2 Posts: 564 ✭✭✭Itsfixed


    King Raam wrote: »
    I thought I posted a reply to this yesterday, weird. Anyway, here is what I thought I said...

    Rear fork is 120mm, BB is 70mm

    If i remember rightly, you bought a new genesis flyer? If so, then the speccing engineer probably considered it OK not to cause any serious problems, wear or even danger. Component choices are probably dictated more by what's available to them than what would make it absolutely spot-on.

    Having said this, I'm never quite sure what way to judge how straight a chainline. On my bike, for instance, if I look at it from the top, it seems slightly out, but if I look at crouching down behind the rear wheel looking towards the cranks, it seems straight.


  • #5
    Raam
    Registered Users, Registered Users 2 Posts: 14,318 ✭✭✭✭Raam


    aye, it's a Flyer. When I got it, it was in freewheel mode. I put it in fixed wheel mode myself so I'm not 100% certain I've done it perfect. It cycles fine, but just sounds a little noisy for my liking. I still love it though and I'm glad I got it.


  • #6
    TinyExplosions
    Registered Users, Registered Users 2 Posts: 6,860 ✭✭✭TinyExplosions


    King Raam wrote: »
    aye, it's a Flyer. When I got it, it was in freewheel mode. I put it in fixed wheel mode myself so I'm not 100% certain I've done it perfect. It cycles fine, but just sounds a little noisy for my liking. I still love it though and I'm glad I got it.

    I'm the same with my Paddy Wagon, but think it could be the cranks making the noise... will take it into cycleogical to get checked at some point :)


  • Advertisement
  • #7
    rp
    Users Awaiting Email Confirmation Posts: 1,227 ✭✭✭rp


    Fixies can be noisy if the chain is too tight. I think about 1cm of play at the tightest point is what it should be. A bit of finish-line 'wet' lube works wonders as well (until you get it on your leg)


  • #8
    Itsfixed
    Registered Users, Registered Users 2 Posts: 564 ✭✭✭Itsfixed


    My pompino came initially equipped with a 1/8 bmx type chain and cog which was fine but noisy i thought. When it was time to replace, and after checking out some forums on fixed gear, I changed to a 3/32 chain (Sram PC48) and rear cog and now its much quieter and smoother.

    The other advantage is that because 3/32 chains are designed to be moved and manipulated about on derailleur gear setups, any slight deviation from a perfect chainline has little effect on performance or ends up being noisy.

    Fixed wheel guru Sheldon Brown doesn't believe that 1/8 chains offer any inherent advantages for fixed gear bikes over 3/32.

    In addition, what I'm finding is that its much easier and cheaper to source 3/32 cogs, chains and chainrings. 1/8 chainrings, in particular, are like hens teeth.


  • #9
    rp
    Users Awaiting Email Confirmation Posts: 1,227 ✭✭✭rp


    Itsfixed wrote: »
    Fixed wheel guru Sheldon Brown doesn't believe that 1/8 chains offer any inherent advantages for fixed gear bikes over 3/32.
    I'm sure Sheldon is right, but after snapping a 3/32" chain climbing the South Leinster Way last year on a fixie, I considered changing to a 1/8", or a Honda Fireblade chain or something....


Advertisement