Facing the front dropouts
There is a little room for expanding the dropout spacing on the fork, it you want everything to line up just so.
Modifying the fork is risky - at this point in production we aren't able to replace forks where mistakes are made in modifications. They're too expensive and we don't have enough of them.
If you want to open the fork dropouts, you can (I haven't, so take this as something of a theoretical discussion) face the inner dropout "bosses" that contact the stub axles (or locknuts, depending on the hub you're using). Temptation is to use a file, but the bosses rest in a "depression" in the dropout that a flat file would damage. To do this properly, you need a dropout facing tool. This is the only one I've found:
http://morningstartools.com/Pages/DropoutFacing.aspx
It's kinda expensive for a one-use tool, but it's cheap insurance if you're working on a part made of unobtainium.
This should give you a precise, parallel set of dropouts and prevent damage to the outer dropout flanges. Use Park Tool Cutting Oil to prevent galling, and work slowly, taking a light cut, then adjusting the tool. If the tool is "catching" or binding, back off and take a lighter cut.
You should be able to get at least 3mm overall increase without too much drama. Could be that you could get the 2.5mm per side that you want.
Good luck. Don't mess up...
Cheers,
Doug
