Cycling in and around Birmingham England

Converting to a single speed

I've got a Peugeot hybrid bike whose derailleur mech has seen better days. Totally knackered in fact, as is the front mech. All else is good. I'm enjoying my loaner single speed so much I'm going to make my own. It'll be my trip to the pub bike with little to commend it to the casual thief.

I can see single chain wheel 48 tooth chainsets on Fleabay. Anything I need to be aware of before I splurge?

The bike I've been riding is 52/21 which flies up hills and is OK on the flat. I don't pedal downhill ever! ;0)

So if I bought a 48 tooth (more common therefore more choice than 52 tooth it seems) then I'd use an 18 or 19 on the back. I realise the BB has to be selected with care to get the right chain line and spacers used with a single cog on the back hub. The current chainset is a cheapie so I don't have the option of unbolting the unwanted cogs.

Any advice/comments?

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Replies to This Discussion

Permalink Reply by Paul Evans on October 2, 2011 at 19:12

Depending on your drop outs, you might need something like this to tension the chain

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Permalink Reply by Jon Ingram on October 2, 2011 at 19:20

Yes, I might, Paul. There's one on the Trek but I may well be able to get away with not needing one - we'll see.

Paul Evans said:

Depending on your drop outs, you might need something like this to tension the chain

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Permalink Reply by BrownhillsBob on October 2, 2011 at 19:35

If the rear sprockets are cassette. you can get spacers and a cog which allow you to put your cog where appropriate. In that case, any need to change the chain set?

Chainline on singles is normally track width at about 42mm. That's from centre of chain stay. but if you keep the rear and add a cassette socket, just at spacers to suit.

Variants of this type of thing:

http://www.chainreactioncycles.com/Models.aspx?ModelID=2300

These guys worth a look, but most stuff cheaper elsewhere

http://www.velosolo.co.uk/shop.html

Best wishes

Bob

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Permalink Reply by Tim Hodson on October 2, 2011 at 19:43

I did something very similar last week. My old 1960s Raleigh royale developed the unnerving habit of trying to throw it's derailleur into the back wheel. The rivetted end of the bolt holding the derailleur had sheared off and so everything was cockeye.

So, I simply stripped off the derailleur and shortened the chain. The Raleigh has nice horizontal dropouts for chain tensioning, and I did 25 miles yesterday with a 46/14 (88.7GI) gearing. And yes, I walked up the steeper hills with gearing like that!

I am planning to change the hubs on this bike in the near future, but for now this impromptu conversion is working well.

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Permalink Reply by Jon Ingram on October 2, 2011 at 20:25

Well, Bob, the BB's knackered so I'll be wanting to replace that and the chainset's a nasty 3 ring jobbie without any of them being removeable. If I'm going to do a conversion, albeit veering towards doing it on the cheap, I'd like to get the clean lines of a single chainwheel.

BrownhillsBob said:

If the rear sprockets are cassette. you can get spacers and a cog which allow you to put your cog where appropriate. In that case, any need to change the chain set?

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Permalink Reply by BrownhillsBob on October 2, 2011 at 20:33

Understood. Most square taper will give 42mm chain line. Recently did it with an Alfine and Stronglight 2000 - Alfine required 47mm so I just used a 10mm longer BB (BB's are measured full length, so half difference of chain line.) Worked a treat.

Best wishes

Bob

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Permalink Reply by Jon Ingram on October 2, 2011 at 20:47

Thanks, Bob. I can tell I've got a lot of reading and learning to do! ;0)

Keep pedalling!

Jon

BrownhillsBob said:

Understood. Most square taper will give 42mm chain line. Recently did it with an Alfine and Stronglight 2000 - Alfine required 47mm so I just used a 10mm longer BB (BB's are measured full length, so half difference of chain line.) Worked a treat.

Best wishes

Bob

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Permalink Reply by BrownhillsBob on October 2, 2011 at 20:51

Like I say, if you're using a cassette adaptor it's unimportant. Chainline and BB combinations are a black art, but that Velosolo site is surprisingly good for info, as is Sheldon. I over thought my issue terribly. In most cases, it's suck it and see and you can get cheap BB's for around a fiver just as a try-out.

Best wishes

Bob

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Permalink Reply by Jon Ingram on October 2, 2011 at 21:01

Thanks Bob.

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Permalink Reply by CKS on October 3, 2011 at 8:11

Would it be possible to just reuse the jockey wheel?

Paul Evans said:

Depending on your drop outs, you might need something like this to tension the chain

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Permalink Reply by allthegearnoidea on October 3, 2011 at 8:50

I rode my single-speed in for the first time this morning and enjoyed it a lot. :)

I expected the chain line to be a problem, but I followed the spec on the single-speed crank and chain ring (43mm chain line with a 110mm BB) and got a converter kit for a cassete hub - the converter had spacers that could land the rear cog in various positions and the first one I tried gave me a dead straight line - dead easy!

Maybe I was just lucky?

rob

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Permalink Reply by Jon Ingram on October 3, 2011 at 19:20

You can but it's heavier than a tensioner, diverts the chain much more than you need, and in my case the whole thing's scrap being bent following a mishap! I'm hoping there'll be enough adjustment in the drop outs not to have to use one anyway.

Chris S said:

Would it be possible to just reuse the jockey wheel?

Paul Evans said:
Depending on your drop outs, you might need something like this to tension the chain