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Gear restrictions for U12 and U14

After dropping his chain twice at Milton, I'm toying with the idea of going single ring on Iestyn's bike but I want to make sure that it will still be suitable for road racing this summer. According to my calculations (700Cx23), 40/14 should be spot on for the 6.05m limit for this year (U12) and 40/13 should be spot on for 6.45m in U14. Can anyone confirm my arithmetic before I start ordering bits!

Cheers,

S.

Comments

  • Hi Steve,

    I've used the following site before - http://www.bikecalc.com/gear_meters_of_development

    I wouldn't worry about U14 gearing yet as Iestyn will probably need a new bike before then.

    Ethan runs a 46/16 for Road and Track which is U12 - 46/15 works for U14.

    If you are hoping to use for Cross as well a 40T would be quite big with the cassette he has. Ethan's is a 38/32 for Cross which is tough on some climbs - I know some of the adults run a 32 or 34 single set up.

    I hope that helps.

    Scott.
  • Thanks Scott. Yeah, maybe I just need to get a 36 or 38 for cross next season - it's hardly difficult to swap a chainring, after all. According to that table, 40/14 is 5cm below the max for U12, so that sounds good - though 40/13 is 1cm over the max for U14 - however, as you mention, I might be shopping for yet another bike by then...
  • Steve,

    I wouldn’t rely too much on any of the published tables or calculators: they can’t take account of the width of your particular rim which affects how tall the tyre profile will stand. When you combine that with the fact that one brand’s 23mm tyre can be 2mm wider or narrower than another’s, gear tables can only be a rough guide.

    Also, for the purposes of circuit racing you can always reduce the overall gearing by fitting a 21mm or even a 19mm tyre, or you can increase it by fitting a 25mm or 28mm tyre (assuming your particular frame has sufficient clearance for wider tyres). Either way you can usually get it within just one or two cm of the limit. But trying to get it any closer than that can result in some anxious moments when the gear is rolled out at races... ;)

    Mark F
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