# Single Speed crank dilemma.



## al-fresco (28 Dec 2011)

Here's the problem... I have an old Saracen MTB that I want to covert to SS as a 'ride to the pub' bike. So I ditched the dérailleurs and rear block, pulled off the crank to remove the 2 unwanted chainrings and... they're riveted on. No problem, there's another old MTB in the garage - I'll take the cranks off that... damn me - those chainrings are riveted on too. As it happens I also have a good MTB frame and crankset that I was saving for when I knew what I was doing. Yes, that has removable chainrings but, wait a minute, it's not a straight forward square taper fixing. So, I've checked on line - single speed cranks are HOW MUCH???

OK - so I'm looking for a cheap solution (£20?), square taper cranks and, say, a 36 tooth chain ring. (Is it possible to drill the old rivets out and fit bolts perhaps?) 

And, while we're on, I'd like to ditch the old combined shifters/brake levers for a pair of basic levers that will operate V-brakes. Would second-hand BMX stuff do?


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## Zoiders (28 Dec 2011)

BMX levers won't give you the correct cable pull in most cases.

You can seperate/unbolt the shifters from the levers on some older shimano STI set up's, worst case scenario is a hack saw and file for some of the Alivio and STX-RC models.

You can drill the rivets out on some chainsets, you will have to check which ring the others ride upon though to see which one will remain on the crank arm once the rivets are gone.


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## biggs682 (28 Dec 2011)

why not just leave the unused rings on !

extra weight wont make any great differance


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## al-fresco (29 Dec 2011)

Zoiders said:


> BMX levers won't give you the correct cable pull in most cases.
> 
> You can seperate/unbolt the shifters from the levers on some older shimano STI set up's, worst case scenario is a hack saw and file for some of the Alivio and STX-RC models.
> 
> You can drill the rivets out on some chainsets, you will have to check which ring the others ride upon though to see which one will remain on the crank arm once the rivets are gone.


 
Thanks for that - I'll have a look and see if the ones I don't want can be drilled off. My V-brake levers are in a one piece molding with the gear shifter housing. They'll do for the moment but I'd like to replace them.



biggs682 said:


> why not just leave the unused rings on !
> 
> extra weight wont make any great differance


 
I did consider that... but I didn't think it would look very good. (Even by my grungy standards!)


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## GrumpyGregry (29 Dec 2011)

ebay is your friend. You'll get some cheap second hand V brake levers from Avid or Tectro and a square taper Alivio, or similar, triple chainset you can remove the rings from for less than £25 if you are careful.


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## al-fresco (30 Dec 2011)

Thanks guys, drilling the rivets left me with a crank with a 40T ring - ideal for what I need, I'll leave the shifters in place for the moment while I get the rear wheel re-dished.


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## TheDoctor (30 Dec 2011)

Another option would be the cheap Stronglight chainset that Spa do.


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## Jezston (12 Jan 2012)

TheDoctor said:


> Another option would be the cheap Stronglight chainset that Spa do.


 
I've seen them, and other similarly cheap Stronglight ss chainsets about. Stronglight afaik are pretty reputable, and a spec of around 450g is pretty acceptable.

There's got to be a catch, right?


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## TheDoctor (12 Jan 2012)

I'd have thought so, but I've not found it yet...


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## tyred (12 Jan 2012)

Jezston said:


> There's got to be a catch, right?


 
They are swaged and therefore perfect for SS freewheel but will eventually break if you use them for fixed and do a lot of leg braking.


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## Jezston (12 Jan 2012)

tyred said:


> They are swaged


 
They are what what now?


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## PpPete (12 Jan 2012)

Bending the metal up inside to join crank and ring - no chunky forged spider to spread the load.


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## tyred (12 Jan 2012)

The chainwheel is basically riveted to the crank arm and if you apply back pressure, it becomes loose and slips over time. I learned from experience. Mine was an old steel chainset so I just welded it up again but that's not so easy with alloy.

See Sheldon's glossary entry  on Swaging (near the bottom).


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## Jezston (12 Jan 2012)

Aha, cheers. I shall avoid such cranks then.


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## tyred (12 Jan 2012)

There would be no problem so long as the bike has a freewheel.


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## GrasB (12 Jan 2012)

I'd go for something with removable chain rings. It'll let you change your gearing more easily & most spidered cranksets are much more rigid which is important when climbing on a single speed or fixed gear bike,


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## Theseus (12 Jan 2012)

tyred said:


> The chainwheel is basically riveted to the crank arm and if you apply back pressure, it becomes loose and slips over time. I learned from experience. Mine was an old steel chainset so I just welded it up again but that's not so easy with alloy.
> 
> See Sheldon's glossary entry on Swaging (near the bottom).


 
Thanks, you learn something new every day.


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## al-fresco (22 Feb 2012)

Thanks for all the help and encouragement on this one. 

The first attempt - using an old MTB crank with the inner and outer chainwheels drilled off wasn't a success. There was a clunk and a slip in the drive chain whenever it was under serious load - to the point that the bike was un-rideable. I tried replacing the chain - which didn't help - and then bought a new Stronglight Crankset (£20 from Spa Cycles) which seems to have cured the problem. 

I threw the old derailleur away and treated it to a 4jeri chain tensioner from Charlie the Bikemonger. The bars and brake levers came off a scrap bike and I'll replace them when I find some better ones.

Thanks again!


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