Mine'sAPint

I want to convert my old mountain to singlespeed so that it doesn't just end up sitting in my garage getting no use, I like the look of the bike and think it's gonna look even better with all the cheap and ugly gear stuff taken off The bike's a 1998 Ridgeback something-or-other, aluminium frame, low end Shimano components (Acera/Alivio mix) with a rigid fork. It has vertical dropouts so I'd use a Singulator to allow me to experiment with different cogs etc.. I want to try and keep this cheap until I hopefully get the singlespeed addiction Well anyway, I have a couple of questions before I get stuck into this:

Chainline. The rear hub is threadon freewheel, so I would just replace the old and busted freewheel with a new singlespeed one. I understand I would then need to respace/redish the rear wheel, does that just involve moving/replacing some spacers and tweaking the spoke tensions to bring the rim back to center ? Should I be trying to get the rear cog to line up with my existing middle chainring ? Is that the normal chainline for a MTB conversion ?

Chainring/crank. My crankset is one of those nasty cheap affairs that is held together by rivets. To start with I would probably just stick with it and run the chain on the middle chainring. In the future I'd want to remove the granny gear and replace the big ring with a bashguard, would I be able to just drill out the rivets and replace them with crankbolts ? If not then I guess I would just get some replacement square taper crankarms.

OK, I think that's all for now, be prepared for more questions in the near future Thanks!

Phatman

I'll be very interested in the answers to this thread...thats exactly what I had in mind for my old mtb.

horndude

Try https://www.jensonusa.com order a surly 1X1 hub laced up to a rhynolite,about $105 with shipping.That will fit the 135mm spacing of your dropouts and set you up for I think about a 52mm chainline....check that,may be 58mm,cant remember.Anyway,that will line up with outer chainring on stock crankset.Replacing that junk crank is a good idea cause it will be the first thing to bend and fail....been there done that.As far as re-using old wheel..ya that can be done I think anyway,redishing it that much may meanspoke replacement on at least one side.My advice,buy a new wheel....its worth it.


Try https://www.sheldonbrown.com in the singlespeed section for more info,he's also got a chainline vs crank table that may help,you will need a longer BB spindle than normal with a single chainring vs a triple.The singulator works,but follow directions closely when setting it up....dont need one if youve got semi horiz dropouts though,just start with gear combos that are divisible by 4 for a starting point..... ie 48/16 adds up to 64 which is divisible evenly by 4.For some reason with a new chain this usually puts you in the middle of the rear droputs....dunno why,never did the math,but it works usually.

Mine'sAPint

Thanks for the advice! To start with I want to try this as cheaply as possible, just to find out if I like it... My problem with getting a new wheel is that my dropout spacing is 132mm, weirdly non-standard... I hear that I shouldn't be bending an aluminium frame but maybe just 3mm would be OK ? Anyway that would be a future thing, I want to do this on the cheap to start with. I'd probably initally use the bike to commute on until I built it (and my legs!) up strong enough for mountain biking.

roadfix

Or.....you can convert your existing Shimano cassette hubbed rear wheel to fixed by using the Surly 'Fixxer'............cheap way to go instead of buying a complete rear wheel.

Mine'sAPint

I wish it was a freehub, unfortunately since this bike had some real low end stuff on it it's got a threadon freewheel The freehub would be great since it looks like you get to choose where the chainline is by just chucking some spacers on the splines. Oh well...

horndude

No it shouldnt be bent....Im just guessing that it would prob be ok anyway,worse come to worse,you just remove a little alum at the dropouts and axle nuts(hub end) and put it on.3mm isnt much....may go on as is w/o screwing with it.You can reuse that old wheel(I think)....Ive laced up wheels w/o dish bfore,isnt hard.....but im guessing your hub is offset as well,that will be a prob Im thinking.Check a local bike store that builds wheels and see what they think.Everytime Ive done one of these the frame stays always were pulled inward when the axle nuts were torqued anyway,there is some leeway there.

Mine'sAPint

Thanks horndude, that sounds like some good options to explore. Something else I was thinking of was whether plain old 135mm freehub wheels come with spacers on the axle ? Looking at this stuff on Park Tool's website it looks there is a small 1mm or so spacer on each end of the axle, I could probably just remove those and have a sweet fit in my frame. That way I'd be able to just get a cheap freehub wheel off ebay and throw on a single sprocket. Any obvious problems with going that route ?

horndude

Dunno if they do or not,the surly 1x1 comes with litle tiny ones.....I know the freehub route is doable,gone that route once myself,I used a cog and a homemade spacer and it worked great.I think you can get a kit to do it that way....dunno,maybe sheldonbrown sells em,I saw them recently online somewhere.The cogs that fit are the same as the ones sold by shimano for their BMX cassette hubs if I remember right.

Mine'sAPint

Just went and stripped all the derailleurs and stuff off the bike. I decided to just double check the spacing, well I'll be damned, it's 135mm after all Not sure how I measured it to be 132mm, probably something to do with only have an "inches" ruler and screwing up the conversion Heh heh.

Now I have a whole bunch more options. I'll probably try and pick up a real cheap wheel just to try singlespeeding out. If I like it I'll get a big burly offroad capable wheel.

It also turns out my bottom bracket is incredibly notchy, the thing has never been maintained (I know better now). I saw a bunch of BB + crank combos on Ebay, I guess anything reasonably strong with bolt on rings is the way to go.

Thanks again everyone for the advice