Another stupid chainline question...
 

I'm converting an older Raleigh road frame into a single speed. The rear hub is 126mm with a spin on freewheel. I'm thinking of getting the cheap Origin8 cranks which according to the website work with 103-107mm spindles. Would a cheap 107mm UN54 BB give me an acceptable chainline with this crank/hub setup? I've been reading threads for the last hour trying to figure it out, but I'm still not sure. Any help, suggestions, info, and insults are welcomed.

was this question?:

a) too complex
b) tired
c) stupid
d) all of the above

They reason you did not get any replies is because you did not provide enough information for anyone to help you.

But let me help you, help yourself.This should have all the information you need to know about chainline. Good luck.

Thanks for the response. I already read Sheldon's article and while very informative, I'm having a hard time figuring out what I need since I'm dealing with a bare frame with no BB or crank on it. I can't measure the existing chainline to figure out how different parts will change it. Also, what information did I not provide? I think the only thing I left out was that the hub is an old Miche Competition. I appreciate any help or suggestions...

First thing: Measure the chainline of the hub. Sheldons page will tell you how to do that.
Second: Figure out the chainline for the crank/BB combo.. I don't remember off the top of my head but I believe the 103mm gives a 42mm chainline with the origin8s .. the site selling will usually list, but u can also ask.
Third: With a square taper BB you can adjust the spindle length to match up with you hub (as long as it is not too short for clearance issues).. so if you need a 45mm chainline take the delta (3mm) multiply by 2 and add it the base known chainline spindle (eg 103 would use 109 for 3 more mm)

+1 for sheldon brown

thanks guys, i'll do some measurements on my hub tonight..... (does that sound a little dirty?) ;)

You're correct. A 103mm bb will give you 42 with the chainring on the inside and 107 will put your ring on the outside on those Origin 8 cranks. Same as Bulletproofs.

thanks man, this is what I was looking for! :thumb: