I have an On-one Il Pompino, which is a single speed cyclocross bike. It has 135mm spacing in the back for mountain bike style hubs. I have a hub on there right now made by the same people who made the frame. The hub is advertised as having a 50mm chainline.
I assume this means that the center of the chain, when mounted on this hub, is offset by 50mm from the center of the bike, correct?
This makes some assumptions - all various fixed-gear cogs and standard freewheels come in some standard spacing. I have no idea what this spacing is, but it looks like it's roughly 1/4" from where the threads on the hub run up against the hub body back to the center of the freewheel. Can Iassume this spacing is standard and taken into account when they say "50mm chainline"? I don't want my chainline changing if I switch from a freewheel to a fixed cog later on.
Ok - here's the meat of this question:
I want to replace the bottom bracket and crankset on the bike with something nicer. How do I go about selecting a bottom bracket and crankset so that I actually get a 50mm chainline to match the hub?
Any help would be appreciated. If I left out any information, please let me know.