"Youth A" Front mech / chainset ?!?

jejv
jejv Posts: 566
edited November 2010 in Amateur race
If I understand right, "Youth A" roadracing is limited to 6.93m rollout, which I think is about 46x14 on 23mm tyres.

Which suggests to me either a touring triple 46/34/24 or a modified compact double 46/34.

But WTF do you shift such a thing with, if you have Shimano brifters ?

Do folks just use normal road mechs, radiused for 53+ big rings ? Does that give reliable shifting ?

~I'd be inclined to modify an MTB mech that's designed for exactly that range, if not the chainline or the cable pull (done this before for 47mm chainline).

This is a problem for touring cyclists, who don't care about downhill gears, and want to maintain constant power/rpm uphill, so they get into strange stuff like modding mechs and "Shimergo".

Comments

  • skellator3
    skellator3 Posts: 200
    better off using a standard double 52/ 39 and standard ratio cassette but setting the stop screws so they cant get the higher gears im sure it either 52 - 16 or 17 thats as big as they can go
    a compact comes up short on the higher gearing a 52 comes out about spot on for junior races you can get a 10 sp cassette 15 to 27 so no need to set set screws high. gives you 6.8 metre roll out close enough in my book and a full range of gears
    dont only ride a bike
  • skellator3
    skellator3 Posts: 200
    just to clear up 52 big ring max smallest allowed at rear is 15 to give you 6.8 metre rollout with 700 x 23 mm
    so either set stop screw on std cassette or get a 15 to 25 cassette for a full set of gears

    53 tooth outer is to big and a compact leaves you short on the bigger gears
    dont only ride a bike
  • Tom Butcher
    Tom Butcher Posts: 3,830
    +1 to Skellator's answer. Most youth races wont be that hilly (are there any really hilly circuits?) so just screwing the stop in on the rear mech should be fine if you don't want to go for the special cassette - the range of gears isn't really needed too much.
    it's a hard life if you don't weaken.
  • Surfr
    Surfr Posts: 243
    Hold on. My cross bike has standard 105 front and rear mechs and was specced with a 36/46 cyclocross race chainset up front. It works faultlessly, even now that I've upped the big ring to a 50t. I'm sure there is no discernable difference between MTB and road mechs as far as chainring size is concerned.
  • love2ride
    love2ride Posts: 224
    52-15 is too big. It has to be 46-14, 49-15 or 52-16. For road the most common youth a combo is 52-16 or 46-14. For track most of us use 49-15.
    Hope this helps.
  • love2ride
    love2ride Posts: 224
    oh yeah, restrict the rear cassette. Makes it much easier instead of finding the right chainrings or restricting the front!
  • Chiggy
    Chiggy Posts: 261
    Don't worry about the radius of the front mech cage. I have a std front mech for a 52 ring being used with a 32 ring.

    The set up is a non-existant 44 chainring with the limit screw wound in.

    As standard, the mech is positioned so it clears the largest ring's teeth by 1.5mm ish. How far does it clear the middle and small ring? And do you have trouble changing up from inner to middle ring?

    In Youth class, go for a Compact with a 46 big ring and a 34 small ring. Fit a cassette with a 14 smallest sprocket. Shimano market a 14 - 25 in most of their road series groupos for this very purpose.

Categories