Replacement freewheel to go faster in top gear

easybiker
easybiker Posts: 21
edited August 2014 in MTB workshop & tech
My 7-speed shimano freewheel MF-TZ21 (14/28 tooth) is worn out and I need to replace it. But I would like to be able to push the bike faster in top gear, as I am freewheeling a lot of the time even on the flat, unable to turn the pedals fast enough! Can anyone recommend a compatible part that has fewer teeth on the smallest sprocket? I can't see a variant of MF-TZ21 that provides this. Front crankset is 22/32/42 and recently replaced, so I don't really want to have to change that again. Any advice most welcome.

Comments

  • rockmonkeysc
    rockmonkeysc Posts: 14,774
    The freehub and cassette are separate components.
    I'm not sure what the smallest cassette ring is on 7 speed cassettes but I expect most cassettes will have the smallest size. You're other option is a bigger big ring on the front, I guess you are riding more on road than off?
    Transition Patrol - viewtopic.php?f=10017&t=13070235
  • easybiker
    easybiker Posts: 21
    No, it's not a separate freehub & cassette. It's an integrated freewheel unit which comes with the sprockets attached.

    If it were a standard freehub/cassette system, I would have no problem finding an e.g. 11/30 tooth sprocket set, but this is a combined unit.
  • cooldad
    cooldad Posts: 32,599
    I don't think you get one.
    So solution would be a new wheel with a freehub.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • stubs
    stubs Posts: 5,001
    I think your stuck with a 14T on a MTB freewheel but you can get road freewheels that go down to 12T iirc. Not sure if its a straight swap maybe Sheldon Brown or Park tools will have the info. You will also be stuck with a fairly small big cog so might need some steel leg muscles.

    http://www.ebay.co.uk/itm/Shimano-Dura-ace-MF-7400-freewheel-12-21-7speed-rear-cogs-screw-on-chain-vintage-/261559791788?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item3ce62db0ac
    Fig rolls: proof that god loves cyclists and that she wants us to do another lap
  • easybiker
    easybiker Posts: 21
    cooldad wrote:
    I don't think you get one.
    So solution would be a new wheel with a freehub.

    Well that's one way. I'll cost it out. Maybe I should have just got a new bike.
  • easybiker
    easybiker Posts: 21
    Or is there a way to convert (easily) the MTB freewheel into a freehub/cassette system? Seems a shame to discard a whole wheel.
  • cooldad
    cooldad Posts: 32,599
    Nope
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • Mister_g
    Mister_g Posts: 55
    easybiker wrote:
    My 7-speed shimano freewheel MF-TZ21 (14/28 tooth) is worn out and I need to replace it. But I would like to be able to push the bike faster in top gear...

    Hi, new here, and prepared to be shot down...

    Is that a 'normal' screw on freewheel?

    It was a while ago, but if it's the same fitting, I replaced an MF-HG-40-7 freewheel (40-14T Megarange) with one that I'm pretty sure goes 28-11T. I can't seen any markings on it, but it would have come from Halfords.

    Maybe one of these: http://www.halfords.com/cycling/cycling ... tte-11-28t

    If this isn't suitable, I'd be interested to understand why (please!).
  • easybiker
    easybiker Posts: 21
    Mister_g wrote:
    easybiker wrote:
    If this isn't suitable, I'd be interested to understand why (please!).

    This is a cassette for a freehub/cassette system. I need a freewheel.
    See http://sheldonbrown.com/free-k7.html for clarification.
  • jimothy78
    jimothy78 Posts: 1,407
    easybiker wrote:
    Or is there a way to convert (easily) the MTB freewheel into a freehub/cassette system? Seems a shame to discard a whole wheel.

    Well, you could save the rim and get it re-built onto a different hub, but that's likely to be more expensive than just buying a cheap new wheel.

    One thing to bear in mind, though, is that a lot of folks on this forum use 1x10 gear systems that actually have a lower "top gear" than yours (42/14 is exactly equivalent to 33/11 - and on lots of 1x10 systems, top would be 32/11). I suspect that the difference is in the type of trails being ridden; If you're regularly spinning out your top gear, then I presume you're riding a lot of fireroads or tarmac - try finding some more interesting offroad trails - lots of corners, technical features or just twisty narrow singletrack will make your current top speed feel insanely fast, and force you to slow down a bit. Undulating terrain can also be "pumped" for extra speed, even if you're travelling at speeds that would be impossible to pedal...
  • Mister_g
    Mister_g Posts: 55
    easybiker wrote:
    This is a cassette for a freehub/cassette system. I need a freewheel.

    D'oh! Sorry - I thought I had linked to a freewheel (I understand the difference). Whatever, it was definately a *freewheel* that I found with an 11 or 12T small sprocket.

    Hmm... looks like they are no longer available: http://harriscyclery.net/site/itemdetails.cfm?ID=1724

    Sorry!
  • easybiker
    easybiker Posts: 21
    jimothy78 wrote:
    I presume you're riding a lot of fireroads or tarmac - try finding some more interesting offroad trails...

    Unfortunately I have to cover a fair amount of tarmac to get to the off-road stuff.

Categories