Chainline help needed...
 

Ok, here goes. I'm having Carl Strong build me a ss road bike. I have a set of blue Phil Wood Kiss-off hubs in 135mm spacing that I am going to run on the bike (with white velocity deep v rims, drool). I'll have the rear triangle spaced to 135, so my question is this:

I have a line on a C-Record road crank (the most beautiful crank ever made in my opinion), but I want to understand if my chainline will work with the 135 rear spacing. Can I get a Campy triple BB w/ 111mm spacing to work with the crank? How does one figure thie chainline out without trial and error, without buying lot of expensive BB's, and before I have my frame made?

help...

have you looked at this page? http://www.sheldonbrown.com/chainline/

ok, I read that article, and it's saying that my rear hub chainline from center to shoulder is 45.35mm, great, I get that, and my freewheel (white Ind. ENO) is 8.73 from shoulder to chainline. So do I add 45.35 + 8.73 or do I subtract 8.73 from 45.35??? And then how do I know what my chainline on the crank/bb combo will be without it installed on the frame?

ok, I re-read it and it says to add the two numbers together, but that results in a chainline of 54.08, which ~seems~ wider than any bb/crank combination listed on sheldon brown.

I (still) don't get it! Am I dense?

First you would need to know what size BB the C record cranks call for as a double.
Your chainline in the rear would be 54.08
And most road doubles use a 46mm chainline on the outer ring, you would need a BB 8mm longer than the original road BB.
Which might be hard to find for campy taper.

look into possibly getting a phil bb. they're adjustable by 5mm as well, which might help get your chainline correct.

You can find one...Phil makes lots of really wide square taper bbs that fit campy.

But I don't know for sure how to help without trial and error. The place to start would be normally be to figure your front chainline. Why don't you just pm sheldon brown he's reg'd on this board, or give him a call and ask him. Tell us what he says.

the mathmatical equation is:
[Over locknut dimension - (cog to inside fork x 2)] / 2 = chainline for rear
Use order of operations. If you don't know order of operations, you shouldn't be trying to figure things like this out. Get your GED. knowledge is power!

Def start with the front. Unless your chainline is wicked off, it'll give you a good reference point to let you know if your math is somewhat correct.

Actually that would be from the inside of the dropout to the centerline of the cog.

And wouldn't the chainline be closer to 52mm (45.35 hub + 7.05 DA cog)? Thats about what I got with my fixed Cross-Check. In reality, theres a bit of variation from the advertized values.

And I don't even have a GED.

Can't this be simplified to: (O.L.D. /2) - [cog to inside of fork] ??

Jim

That requires schooling in Differential Equations and the application of Laplace Transforms.

Haha. I knew when I posted it there'd be a select few who'd try to make some sort of quadratic equation or something out of it. Chainline shouldn't require a TI-83. I'm gunna go drink away the math hole I dug myself into.