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running single chainring

speedbumpspeedbump Posts: 416
edited July 2007 in Workshop
If I remove my front mech (it's broken), and just use the big ring (flat TTs), will I have any problems such as the chain coming off or anything?



  • BlondeBlonde Posts: 3,188
    Chain line and tension - I think you'd have to only use it in the smallest sprockets in order to keep the chain line and the chain taught enough. You may find it slips down onto the inside of the chain set wihout one of those dog fang things. Last weekend I managed to unship my chain into the BB where it got stuck. Had to break and remove the chain in order to get it out!
  • I used to commute on 1x9 which worked ok as long as i didn't put loads of pressure through the system.
    It would derail up hills and under acceleration, so i ended up 'fixing' a front mech to keep it on.

    Mleh Mleh Mleh
  • rgismergisme Posts: 1,598
    I think chain line would be an issue. On the point of tension the problem is more likely to be the chain becoming overtight rather than not taught enough if you go into the lower or lowest gear with it as well as being too far offline, so you might well reduce your range at the rear too.
  • speedbumpspeedbump Posts: 416
    Oh. I suppose I'll have to leave the front mech on then until I bother buying and fitting a new one.
  • I've run a 1x9 with no problems, but I did use a "locked" front mech as a keeper. Cheaper than the task-specific chain retention devices made for d/h racers.

    "Not much to see,
    Not much left to lose"
  • llllllllllllllll Posts: 503
    I use a single chainring on the front on all my bikes, none of which have front derailers. You can usually solve the chainline problem by mounting the chainring on the inside of the cranks (where the small chainring would normally fit), but it depends on how much clearence you have. Another way is to use a shorter BB axle or a track chainset, though these would be more expensive than just buying a new derailer. Ideally you should also use a single speed chainring, these don't have the ramps and pins so are harder for the chain to derail, but I've got away with standard chainrings in the past. The important thing to remember is to shorten the chain as much as possible. It needs to be really tight otherwise when you hit a pothole it sends a shock wave (for want of a better description)through the chain which derails when said wave hits the chainring.
  • domtylerdomtyler Posts: 2,648
    edited March 2011
    Leaving the front mech is the simpler solution. Adjust the limiter screws so that it wont move.

    Porridge not Petrol
    Myositis forums
    Porridge not Petrol
  • I rode without a front mech for about a year. No real problems, you just have to be careful about applying power when you are changing gear. other than that it was fine.

    Having said that it did fall off a couple of times, and for the hassel of fixing the mech so it does not move vs. the grease of having to put your chain back on... i would chose the fixing everytime (now, at the time I only did not replace the mech as it was spirited away by a family member for use on their bike)...
  • urbanfatboyurbanfatboy Posts: 193
    there's that little plastic thing in this months mag reviews that might help
  • John.TJohn.T Posts: 3,698
    Leave the mech on. Just ask David Miller.
  • andrewgturnbullandrewgturnbull Posts: 3,861
    Hi there.

    You won't need a front derailleur if you fit a track chainring. Not only does this not have ramps in the teeth, but the teeth are significantly longer - so there's no chance of dropping the chain, even if you chainline is off.

    If you want a track style chainring that will fit a standard chain (rather than the wider track ones), then MDT will sell you one with as many teeth as you need. See

    This setup is very common on the TT circuit.

    Cheers, Andy
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