Fixie conversion - help needed

mozejo

I've got an old hybrid that I'm thinking of converting to a fixie . How hard is the process and how much will the bits cost me ? It is for use commuting in London - with a trip up and down Demark Hill every day thrown into the mix. All advice gratefully received.

el_presidente

Process is medium difficulty

bits will cost you anything from £0 to £100 if you need a new wheel

you need a frame with horizontal dropouts

mozejo

if I don't have horizontal dropouts is there some form of conversion thing I can attach to existing frame ? And how will I know if I need a new wheel ?

el_presidente

a) no
b) if you can't attach a screw-on fixed cog to your existing wheel

I think you may be confiusing single speed and fixed

Lbaguley

As el-presidente says, it is easiest with horizontal dropouts in order to tension the chain, otherwise its an almost impossible task of getting the right chainring and spocket sizes to ensure that your chain is tensioned correctly. Don't think there is any conversion ket available for this, but I may be wrong...

More help might be available at http://www.bikeradar.com/forum/viewforum.php?f=40013

sarajoy

I think that if you have no horizontal dropouts, you can cheat, and put in a sort of in-line jockey wheel as a tensioner - or mod your current one to go the other way - or something....

Aha: http://www.londonfgss.com/thread19372.html

mozejo

Thanks for the ifo - I'll look at it over the weekend and come back with some more questions as to what it looks like and then maybe we can have some more discussion !

What else shall I check ? Dropouts / screw on fixed cog are just for starters I guess

I'm not looking to spend much on this

wgwarburton

sarajoy wrote:

I think that if you have no horizontal dropouts, you can cheat, and put in a sort of in-line jockey wheel as a tensioner - or mod your current one to go the other way - or something....

Aha: http://www.londonfgss.com/thread19372.html

This works for SingleSpeed (SS) but not for Fixed Gear (FG). There are a couple of things you can do to make FG work with vertical dropouts but they do make life harder.

OTOH riding fixed isn't really about making things easy for yourself, so why start with the fettling?

If you were prepared to buy your way out you can get an eccentric rear axle (or even BB?!), this allows enough give & take on the axle to cope. White Industries make one and it isn't cheap!

You can carefully select your 'ring+sprocket sizes to get a "magic gear". There are online calculators to help with this, too. This is elegant.

You can use a half-link (if necessary), a file and QR axle to get just enough play on your dropouts to overcome a small correction. This is a hack, and some reckon fixed & QR don't play well together, but it's do-able.

You can use a ghost ring, allegedly. I havn't seen this done and it's asserted that it's a PITA to get dialled in, but it'd be pretty cool, albeit just a touch inelegant.

Have a look at Sheldon Brown's FG conversion page and a couple of others on the 'net to get some ideas.

You could drop the notion of going fixed and go SingleSpeed instead (using one of the abovementioned tensioners, however you will not be able to shake the nagging suspicion that you may actually be a Wuss...

Cheers,
W.

mozejo

think singlespeed may be the easier option , and Warburton I may just be a wuss ! Seriously though my amount of free time is limited and hence my appetite for complex fettling very slim indeed ( hindered also by fact that I am hopeless when it comes to anything practical )

marchant

My own (still ongoing) S/S conversion has cost less than £30, with more than half of that on tools. In terms of time, most of it has been doing things like tidying up the frame and wheels, actual bolting things on/unbolting them has only been a fairly small part. I found Sheldon Brown's article (here) to be very useful, plus a few others here and there. Google was useful too, for hunting down technical manuals for used parts.

mozejo

that's a great article marchant thank you - I'm going to read it , look at my bike , think about doiing it , retire to the sofa and give up - no , seriously that looks like the right place to start the planning.

mozejo

that's a great article marchant thank you - I'm going to read it , look at my bike , think about doiing it , retire to the sofa and give up - no , seriously that looks like the right place to start the planning.

Greg T

WGWarburton wrote:

Cheers,
W.

BUNS IS BACK!

Where've you been? We've missed your actual understanding about stuff rather than the stock in trade gobbing off and fabrication we peddle. (or pedal)

itboffin

fixed phish! single speed is the way forward- £10 ish for a freewheel single speed kit job done or better yet just take your dérailleurs off and wrap the chain around your existing cassette.

Simples ...!

wgwarburton

Greg T wrote:

WGWarburton wrote:

Cheers,
W.

BUNS IS BACK!

Aww, did you miss me? :-)

Where've you been? We've missed your actual understanding about stuff rather than the stock in trade gobbing off and fabrication we peddle. (or pedal)

Was out-of-contract for a while... no job/no commute! Now back in the saddle, as they say...

Did I miss much?

Cheers,
W.

biondino

What is a ghost ring?

wgwarburton

biondino wrote:

What is a ghost ring?

extra ring between chain ring and sprocket. Spreads the chain apart to shorten it, then hovers, spinning, in the middle while you pedal...
Spooky....
Cheers,
W.

petejuk

What is a ghost ring?

http://www.mtbr.com/ssfaqcrx.aspx
I think this explains most things as well as the types of other SS conversions. (Keep scrolling down)

marchant

Mozejo - durn it I forgot another useful resource - Youtube. Search for "singlespeed" (sorry) or these were/are good. There's eight in the series, plus a few others about headsets, chain tension etc. Charlie the Bike Monger has got a few vids there as well, like this

mozejo

I am humbled by your help. Will watch the videos first and then get going. Muchas gracias.

choirboy

WGWarburton wrote:

Did I miss much?

IIRC there was a really interesting thread on RLJing..... :roll:

Buckled_Rims

here's what I did for a singlespeed MTB.

1. Got an old cheap MTB.
2. Drilled the rivets out of the triple crankset, leaving the 32 tooth cog all by itself.
3. Bought a SS conversion kit with tensioner and 16t sprocket from on-one.
4. Took 8 speed cassette off and replaced with 16t sprocket includes spacers.
5. Made sure the tensioner had a perfect straight chainline.

The ratio might be too low for roads and commuting. But, the average speed has only been 2 mph less then my 27sp XT geared bike! Mind you I pedal a lot faster! Everyone who's ridden the bike has remarked on how smooth the pedaling is due to straight chainline.