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Converting an old racer to a single speed

blobbiblobbi Posts: 42
edited August 2011 in Road general
So I break everything and today was no exception. I had lent my bike to my bro whilst I was abroad. I took it out today to cycle to work and whilst going up hill change into a lower gear, thing is it had been service by his mate and the back tensioner moved in too much and got caught in the spokes. It ripped the teniosner and bent the derailleur as well as chewing up the thread so I can no longer put a back tensioner on it. censored .

So my question is can I convert it to a single speed? It is a semi horizontal dropout but I cannot put a chain tensioner on the back. Is there a chain teniosner that can conect to the frame at the back rather than to where the derailleur is meant to thread in? Is a cheap process that I coudl do myself as it will probably be only a tempory meaure until I get a new frame.


  • mz__jomz__jo Posts: 398
    If it has semi-horizontal drop-outs (as distinct from vertical ones) why would you need a tensionner? I have short semi-horizontal ends on my Gitane and I can handle a variation of one tooth at the rear wheel without any problem. (in my case I have an 18t freewheel and a 17t fixed on a double sided hub).
    If you need to fit a tensionner you may be able to replace the set-scew that goes into the frame with a nut and bolt. Drill out what's left of the thread or take it out with a file. If you don't mind spending money ask your LBS to simply clean up the thread in the derailleur boss with a suitable tap.
    Always round I don't see a vast catastrophe. Worst case scenario you cut off the gear hanger and replace it with a separate one as used on cheap Shimano derailleurs on censored mtbs. Might need to play with the quick release skewer or use a solid axle in the rear hub but even that isn't terrible.
    You really want an excuse to buy a new frame? Don't show this post to your wife or girlfriend in that case!!!
  • If you get the chain length right you won't need a tensioner for your frame. To fine-tune the the chain length you can use a half-link:

    Or use a chain which is composed entirely of half-links:

    I'm sure that neither of the above are the only suppliers, they're just what came quickly on Google.
  • blobbiblobbi Posts: 42
    thanks for the replies, this was surprisingly easy to do.

    The only problem that has come up is that my rear hub turns out to be a niche rather than a campangolo. This has meant that I have had to use one of my current cogs on the rear. Wored out cheaper and did everything including buying some tools for around £60. Out of interest I am using a 38T 19T combination that seems to be ok.
  • mz__jomz__jo Posts: 398
    38/19 sounds very low to me (and I gear low compared to most people on here and fixie forums). 38/16 is rather closer to what I use, in fairly hilly terrain.
  • blobbiblobbi Posts: 42
    Ok mz__jo, so I changed it to a 38:15 (it was actually a 38:17) which I hope will give me a little more of an easy ride on the flat.

    What I wanted to know is there is this, I have pair of Mavic MA40 rims 700cc for my old racer. They have done me well and remained true. However as I am having problems with the fact that there is a niche size cog on the back I can not seem to find any dedicated single speed cogs that can be used in this conversion. There is a MA3 on sale on ebay with a quango single speed hub and I wondered if this would be a good idea to get as I can get a dedicated single speed 1/8th 16T rear hub for this? ... AGB%3A1120
  • mz__jomz__jo Posts: 398
    I can't see enough of the wheel to make a judgement worth having. So far it's cheap! I can't make sense of the hub other than there aren't any tracknuts on it.
    If your old hub is a miche, miche fixed cogs are (were) fairly easily available, check out all the usual web suppliers. I will have a look and post. I don't know how the carrier system works though. I've only ever had the normal screw-on sprockets.
  • mz__jomz__jo Posts: 398
    I have just googled the following term "miche track sprockets" and the response is a page full of suppliers, including Wiggle and Evans. The carrier looks like it ought to unscrew with a normal chain whip.
    Don't forget that a fixed sprocket lockring is normally a left-hand thread (goes on and off backwards) and the sprocket is a normal right-hand thread. A vice fixed to a solid workbench can be useful for holding the lock ring (you the turn the wheel) if it is stubborn. When I was younger I did my sprockets like this and cleaned up the teeth with a file afterwards!! Didn't stop them working. A chain whip with a short tube as an extension is a better way.
  • blobbiblobbi Posts: 42
    I know but they do not look like they will fit my current cassette. They have round inserts like this: ... _thumb.jpg

    that I think fit a screw on cassette like this for track use ... e/ms18.jpg

    but as I am retro fitting to a normal cassette for a road bike I can not find something. I know niche make a lot of 3rd party cogs for campo and shimano but unfortunately I cannot find anything to fit, the shimano have the wrong shaped bits and the campy cassette is too big.
  • mz__jomz__jo Posts: 398
    Sorry I had the impression you were talking about fixed sprockets. What exactly is fitted to your current wheel, a multi-speed freewheel, a cassette or a single sprocket (free or otherwise).
    If it is a multi-speed freewheel you will have to remove it entirely by unscrewing it from the hub (which will require a certain number of tools and a certain knack) and on the thread that will be exposed you can screw on either a single-speed freewheel or a fixed sprocket (but you will not have the place to fit a fixed-gear lockring). You may need to play with spacers on the hub axle, behind the sprocket or on your crank to get the chainline right.
    If it is a cassette you will need the relevant tools to remove the cassette (normally a chainwhip and the tool to undo the cassette lockring) from the hub freebody. There is nothing to be gained in removing the freebody (the freewheel part) from the hub (unless you are launching into a complete rebuild of a Shimano hub with the Surly fixed conversion - but just for now don't even think of it). Onto the freebody you can fit a single sprocket and a set of spacers. This is much simpler than a freewheel hub for correcting the chainline, but you cannot fit a fixed-wheel sprocket.

    Read this first and if in doubt ask a bike shop to remove your freewheel or cassette, it won't cost a lot more than investing in the tools and it will be a lot less painful.
  • mz__jomz__jo Posts: 398
    I don't think there are any single-speed kits to fit to Campag cassette hubs, they are pretty much all Shimano compatible. If the Shimano type spacers will fit you could always butcher a Campag cassette to separate the individual sprockets but sprockets intended for single-speed operation have a better tooth profile.
  • blobbiblobbi Posts: 42
    Ha, I think that I've worked it out. My local bike shop, I'm sure some of you use it being close to Richmond Park, got it wrong.....again and tried to sell me a new rear wheel.

    I think that I have an old 8 speed ultra drive version it looks like the middle on one in this photo on the follow link as it has a slightly narrower spline on to orientate it.

    The campagnolo free hub must be a dedicated 8 speed as it is a little wider than the cog that I bought to convert it to a single speed which is apparently designed for a campy 10 speed.

    So my question is, is there a single speed back cog for an old 8 speed campy free hub?
  • mz__jomz__jo Posts: 398
    I have seen your LGFSS post. If they can't help you I don't know who can.
  • Monty DogMonty Dog Posts: 20,614
    FWIW spline pattern on Campagnolo 8 speed is different to 9/10/11 so you'd have to take a file to current sprocket to make it fit.
    Charlie the Bikemonger sells a Campagnolo-compatible single speed kit for a freehub body.
    Make mine an Italian, with Campagnolo on the side..
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