converting a ten speed to a single speed

hey ya'll- i'm sure many of you have converted geared bikes to single speeds. I'm considering doing that myself also. I'm finding lots of info about what to do with the rear of the drive train- spacers, a chain tensioner, and all that jazz. I'm not finding too much concise info about the front. I know I need to get a ss specific chain ring, but i'd rather get a shiny new crankset than put on a new chain ring/bash guard.

my question is, is there a means of measuring the bb shell to be certain a new crankset will fit, or are most of them universal? i assume that you can buy most cranksets with a new bb included.

Tags: bottom, bracket, crankset

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Permalink Reply by John W. on August 10, 2012 at 2:27am

I've done one recently. Bottom brackets need to match up to the crankset (i.e. JIS threaded for a Sugino crankset). I don't know why you'd need a chain tensioner unless you want it. This should help with bottom bracket sizing.

http://sheldonbrown.com/bbsize.html

Good luck!

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Permalink Reply by MagMileMarauder on August 10, 2012 at 2:52am

I see a lot of 10 speed -> SS conversions riding around with loose chains. It seems like a tensioner would solve that problem. I think that unlike a track bike (with track ends), you can tighten the chain so far with bikes that have vertical dropouts (i.e a 10 speed). Not sure if it's possible to reduce the number of chain links to keep the chain tight instead of using a tensioner.

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Permalink Reply by Duane Waller on August 10, 2012 at 6:22am

What brand bike is it? 10-speed bikes are old enough that you won't need to worry about a chain tensioner; 10-speeds were around before vertical drops were popular. Up front, it depends on the type of crankset/bb shell you presently have; is it a 3-piece crankset, or a one-piece Ashtabula (like on a Schwinn Varisty/Continental)? That'll let you know what type of crankset/bb you need to upgrade to.

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Permalink Reply by Paul on August 10, 2012 at 10:15am

When I seen spacers and chain tensioners I had to add this...
http://whiteind.com/rearhubs/singlespeedhubs.html
It an eccentric rear hub. Just another option. I use one on my mountain bike. Works great and looks great. It is also a flip flop hub so you can have fixed gear on the other side. I think these other guys have you covered for the bottom brackets.

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Permalink Reply by notoriousDUG on August 10, 2012 at 10:30am

There is a lot more to it than most people think.

First there are a lot of important questions to ask:

1. Does the frame have horizontal drop outs?

2. What is the spacing of the rear triangle?

3. Does it have a freewheel or cassette hub?

4. Do you just want a single speed or would you want to have the option to use a fixed cog as well?

5. What is the crank set on it now?

You may not need a tensioner or a new crank depending on what is there. Post good pictures of the bike with close ups of the crank, rear drop outs and wheel.

Better yet take it to a good bike shop and talk to them about converting it; any bike shop worth a shite will give you a wealth of info on properly converting the bike for free and with little pressure to buy stuff from them.

If anyone wells you to cut anything off the bike immediately stop listening to them.

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Permalink Reply by Carly on August 11, 2012 at 3:15pm

here are some detailed pics of the drivetrain. the bike is a takara, probably from the late 70's early 80's.

Attachments:

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Permalink Reply by notoriousDUG on August 11, 2012 at 8:52pm

That crank is not the best suited to a single speed but it can work.

Based on the rest of it I am going to guess that it has horizontal dropouts but a pic of the rear of it would help.

You can convert that with a new rear wheel and may, or may not, need a new bottom bracket to get the chain line right and nothing else.

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Permalink Reply by Carly on August 11, 2012 at 9:44pm

My frame has vertical drop outs, which is why i would like to have a proper chain tensioner. I also like the look of the chain tensioner- its both odd and delightful in my opinion, and probably useful. I'm just going to remove the cassette and put in a freewheel with spacers and keep the hub and wheel. the back i've got pretty much figured out.

on the front, i'd like to put something like this- http://www.amazon.com/Origin8-Square-Track-Bicycle-Crankset/dp/B002... again, for oddity and delightfulness. I want to replace the the crankset altogether. my ultimate question is, can i just slap this crankset on my bike?

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Permalink Reply by Duane Waller on August 11, 2012 at 10:22pm

Wow, vertical drops? Neato!

That crankset should fit onto your current square-taper bottom bracket, but dug would know for sure (I think there may be different sizes?). And you might consider upgrading from the caged bearing/fixed cup bb to a modern sealed unit. Fairly inexpensive and they're easier to upkeep. But getting the fixed cup out might be a drag :(

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Permalink Reply by notoriousDUG on August 12, 2012 at 1:48pm

I am very surprised to hear that bike has vertical drop outs and that it takes a cassette rear wheel. Has the rear wheel been replaced at some point? Can you post a picture of the wheel and drop out for me, I am interested to see a vertical drop out from that era as I have never seen one before.

I am confused by some of your nomenclature, you cannot put a freewheel onto a cassette wheel. Can you explain more about what you are planning to do with the rear wheel? Does it have a freewheel which threads onto the hub or a cassette that slides onto a freehub body and is retained with a lock ring?

That crank should work but you should go with a narrow bottom bracket. However if you are converting with a spacer kit on a free hub body you should be able to compensate and get a decent chain line by moving the cog out more than normal.

Carly said:

My frame has vertical drop outs, which is why i would like to have a proper chain tensioner. I also like the look of the chain tensioner- its both odd and delightful in my opinion, and probably useful. I'm just going to remove the cassette and put in a freewheel with spacers and keep the hub and wheel. the back i've got pretty much figured out.

on the front, i'd like to put something like this- http://www.amazon.com/Origin8-Square-Track-Bicycle-Crankset/dp/B002... again, for oddity and delightfulness. I want to replace the the crankset altogether. my ultimate question is, can i just slap this crankset on my bike?

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Permalink Reply by Carly on August 12, 2012 at 6:29pm

welp, i brought my bike over to smartbikeparts, and the owner said it would cost hundreds of dollars to convert my bike. i'm going to abandon the idea and just buy a new single speed bike. thanks for your help.