frame spacing and wheelsets
 

hey

i'm building up my dads old racing bike into a fixie, the frame spacing is 125mm however i bought a second hand track wheelset for it in order to keep down the cost of having one built for me. When i put the rear wheel in the chainline is well off. Could anyone help out with advice? Im guessing its becuase the wheels were built for a track frame with smaller spacing?

Will the wheels be compatible? is it a case of getting the right crank/bottom bracket combo to get the chainline straight? or are they just totally incompatible?

Any help greatly appreciated, cheers

Dave

Probably both. Grab a ruler or a tape measure and see if you can measure your chainline on the crank and on the wheel. Compare them and come back to us with what you find out.

well i havn't even put a chain on it yet. Basically i've got the BB and Crank it came with and i bought a second hand track wheelset. I used a bit of string to determine whether the chainline would be straight and it isn't at all!!

When you say measure the chainline, how do you mean? can i do it without putting a chain on? It seems that the hub is too narrow!! even if i tried to space the sprocket, there wouldn't be enough thread!

but i'm guessing loads of people do this, so there must be a way?

You can get a new rear wheel build on a wider hub like a miche. Or get a shorter BB and move everything inwards from teh crankside. I dealt with my chainline problem by redishing the wheel out as far as I could to the right and getting shortest possible BB without having the crank or chainring hit the chainstay

The spacers go on the axle. It's to make inner part wide enough to fill the space between the dropouts. You don't do anything with the cog; that would be weird.

I'm guessing that the chainline is wider at the chainring than at the cog. Take a look at your BB spindle. A lot of old road bikes have offset spindles so that you can make it shorter/longer by flipping it around. I've had to flip the spindle on both of my gf's bikes (an old Peugeot and a Fuji Monteray) in order to get a decent chainline. We had to put the chainring on the inside of the crank spider for the Peugeot as well, so you've probably still got options after you re-space the axle.

Wow you were right about the bottom bracket mathletics. Flipped it round to the shorter side and the chainline's pretty much perfect now!! cheers