Chainring for fixed/singlespeed from triple/double

CramCycle

This will come as a stupid question to those in the know but is there a reason why I can't take the large ring of a triple/double chainset and use it on a single speed/fixed? or am I OK to go ahead and try it?

Tonyandthewhale

Could be wrong here but I think I read somewhere that the teeth on double and triple chain-rings are designed to shed the chain more easily so as to make things easier for the front derailleur. This would obviously mean you'd have a tendency to drop your chain a lot if you used one for a fixie. However I don't have a source for this information so it's possible I'm mis-remembering it/dreamt it.
Having said that though if you haven't heard of anyone using a ring from a triple/double chainset (and I haven't) then there's probably a reason for it and I'd advance with caution if I were you.

CramCycle

Tonyandthewhale wrote: »

Could be wrong here but I think I read somewhere that the teeth on double and triple chain-rings are designed to shed the chain more easily so as to make things easier for the front derailleur. This would obviously mean you'd have a tendency to drop your chain a lot if you used one for a fixie. However I don't have a source for this information so it's possible I'm mis-remembering it/dreamt it.
Having said that though if you haven't heard of anyone using a ring from a triple/double chainset (and I haven't) then there's probably a reason for it and I'd advance with caution if I were you.

I thought similar and I also think the teeth might be slightly thicker on a track/fixed/single speed for the reasons you said. I was just thinking if the chain line was good and the chain tensioned enough, it might be fine but it was just something I was mulling over for the future.

Dizraeligears

I have a road frame converted to singlespeed/fixed.I had the frame(steel,horizontal dropouts) and wheels(Goldtec hubs on open pros) and I knew the chain line for the hubs is 45mm.Had an Ultegra triple chainset,and the chainline for this is also 45mm on the middle ring .
So got some track chainring bolts,took off the inner and outer rings.42/16 and perfect chainline.So worked fine for me!

abcdggs

as said road chainring teeth have ramped side to aid in shifting, but as said if you keep good tension it'll be fine.

kumate_champ07

it can be used if you get a perfect chainline, otherwise you risk the chain coming off. I know because it happened to me and the chain tension was pretty good.

not sure about the bottom bracket options for octalink but if it's square taper you have more choices.

this will give you the spindle size for derailler use, you then subtract whatever amount of mm you need to get the chainline right

http://www.sheldonbrown.com/bbsize.html#shimano

for instance, my shimano 6400 double crankset has a recommended matching 113mm BB for a 43.5mm chainline, this measurement is made between both chainrings so it translates to 46mm chainline on the outer ring.


most track hubs have a 42mm chainline which would require 105mm axle length to be compatible with the 6400 crankset, so 103mm or 107mm BB would give me a chainline which is 2mm off, not too bad.

flipping the cog around so that it is facing inwards will move the chainline to around 45mm. that would mean I could use a 110mm bottom bracket and be within 1mm of perfection

kumate_champ07

not sure anyone asked about chainline details but its there anyway..

abcdggs

@kumate- just put an octalink bb on my FG with a double crank. the shortest i could find was 109mm but with the chainring on the inside it's pretty close to perfect.