Another silly question

pockets
pockets Posts: 8
edited April 2014 in MTB beginners
Why sort of speed will I be able to get on single cog on the front with 30 teeth and 8 speed on the rear 11-30t with alivio mech and shifter if that make a diffrence

Sorry agin guys just wondering

Comments

  • jimothy78
    jimothy78 Posts: 1,407
    Another silly question

    Correct.
  • mcnultycop
    mcnultycop Posts: 2,143
    It depends how fast you can pedal.
    Nerve AM 7.0
    Scandal
    Felt Roadie
  • cooldad
    cooldad Posts: 32,599
    Speed = 30/11(pi x D)x revs.

    Possibly.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

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  • pockets
    pockets Posts: 8
    Sorry I'm trying to get back into biking but never done a bike like I have as I just put up with what ever I had lol
  • The Rookie
    The Rookie Posts: 27,812
    The cadence (pedalling speed) most people will be comfortable to is 120rpm (you can push upto about 160rpm in short bursts).

    Assuming a 2" rear tyre, which would have a 26" diameter, 120rpm on a 30:11 (your top gear) is 25mph, overspinning to 160rpm would see you at about 33mph on a downhill.

    Cooldads Calc is OK as far as it goes but won't give you an answer!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • njee20
    njee20 Posts: 9,613
    Even 120 is rather fast to sustain for any length of time. 100 is a more realistic cadence for longer rides, which would be more like 21mph. Still quicker than most people could maintain on the flat, but will be rather spinny downhill.
  • cooldad
    cooldad Posts: 32,599
    The Rookie wrote:
    Cooldads Calc is OK as far as it goes but won't give you an answer!
    It will with a bit of fernangling, but it does include pi. Steak and kidney preferably.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • The Rookie
    The Rookie Posts: 27,812
    Steak and kidney, MTFU, steak and ALE is where it's at!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • cooldad
    cooldad Posts: 32,599
    The Rookie wrote:
    Steak and kidney, MTFU, steak and ALE is where it's at!
    You obviously frequent ostentatious gastropubs.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools

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