chain rings

mamba80
mamba80 Posts: 5,032
edited May 2015 in Track
Does chain ring size matter?
what would be a better ratio ? 52 x 16, 49 x 15 or 46 x 14, ignoring any marginal differences in meters, is there any difference in efficiency ? this is all for Youth A gearing max 6.93 meters.
I ask because at a recent track race, we seemed to be the only ones on 46 x 14 and strangely enough, its just popped up on a FB page also, but I know that people on here know more :)

Comments

  • imposter2.0
    imposter2.0 Posts: 12,028
    There are theoretical benefits to being on a bigger ring on the front (and correspondingly larger rear sprocket), relating to lower friction losses, etc - but in reality I don't think there's any difference.
  • agent nomad
    agent nomad Posts: 93
    As an engineer this could be over though and then some

    Size of chain ring, size of sprocket, how it wraps around each and how the individual links turn around a smaller sprocket, the amount of contact/release friction on a larger one, the amount of links in the chain. This could go on and on but there is a program on ITV4 soon

    I would suggest in all seriousness to have as short a wheel base, as this can help as few things so if you have a choice keep the chain length short and the rear wheel towards the BB/seat tube. You can get half or crank links to help achieve this.

    There are better bigger gains elsewhere
  • devhads
    devhads Posts: 236
    I would suggest in all seriousness to have as short a wheel base, as this can help as few things so if you have a choice keep the chain length short and the rear wheel towards the BB/seat tube. You can get half or crank links to help achieve this.

    If I needed to do the opposite of this i.e a longer wheelbase to fit wider tyres for grass track how would I achieve this. Would it be with a small chainring and cog combination or big chainring and cog combination?
  • agent nomad
    agent nomad Posts: 93
    Longer chain

    Play around with the chain ring and sprocket sizes and gear sizes

    Limiting factor here is the length of the drop outs you are only going to gain around 30mm and many track/velodrome frames are a lot tighter angles and clearances than a grass track frame I plan to use a Langster for grass track racing which has a little more clearance than my Pinarello xtrack
  • devhads
    devhads Posts: 236
    I am currently building up a Dolan Pre Cursa that I know 32mm tyres fit in to but I don't have any chainrings or sprockets yet to play around with. I was thinking 44 x 16 for grass track but was just wondering if a different combination using a bigger chainring would make it easier to get to the back of the dropouts. I guess it's easier to just try different chainlengths than different gearing combinations.
  • agent nomad
    agent nomad Posts: 93
    I don't have a Dolan and some of the following is based on Internet hersay but Dolan frames apear to suffer from the dropouts spreading so I would advise using quality wheel nuts and a torque wrench to do them up as it would be easier to spread/damage the dropouts the further back the axle is.
  • Paul 8v
    Paul 8v Posts: 5,458
    devhads wrote:
    I am currently building up a Dolan Pre Cursa that I know 32mm tyres fit in to but I don't have any chainrings or sprockets yet to play around with. I was thinking 44 x 16 for grass track but was just wondering if a different combination using a bigger chainring would make it easier to get to the back of the dropouts. I guess it's easier to just try different chainlengths than different gearing combinations.
    Let me know what combo works, I have exactly the same bike and tyre combo!
    Road
    MTB
    NEW Cross
    Track/Grass Track/Winter bike
  • devhads
    devhads Posts: 236
    Paul 8v wrote:
    devhads wrote:
    I am currently building up a Dolan Pre Cursa that I know 32mm tyres fit in to but I don't have any chainrings or sprockets yet to play around with. I was thinking 44 x 16 for grass track but was just wondering if a different combination using a bigger chainring would make it easier to get to the back of the dropouts. I guess it's easier to just try different chainlengths than different gearing combinations.
    Let me know what combo works, I have exactly the same bike and tyre combo!

    I've gone for 46 x 16 with 32mm Vittoria XN tubs and 48 chain links and there's plenty of clearance.

    Are you coming to Ashwell on Sunday for the first race of the season?
  • Paul 8v
    Paul 8v Posts: 5,458
    I would love to go but I can't make it, marshalling our 25' that day :-( I'l be at the next one, not sure when it is though.
    Road
    MTB
    NEW Cross
    Track/Grass Track/Winter bike
  • devhads
    devhads Posts: 236
    West Suffolk Wheelers on 7th June. It was very hard by the way, much tougher than the velodrome and pretty hairy going round the bends at speed. I came 12th out of 16 in the omnium, did much better in the endurance races than the sprints.

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