I have a Vent Noir with first generation Dura Ace hubs laced to 27" rims that look similar to Mavic MA2s. The wheels appear to be in excellent mechanical shape; although definitely well used. Although suspect that everyone here will already know this, the hubs are freewheels and the rear drop outs at 120 mm.
I'm thinking that a second set of wheels for everyday use would be a good idea since the wheels are probably ~30 years old and I'd like to keep as much of the original bike in working order. My thought is to spread the rear drop outs to 123mm such that fitting both the original 120mm wheel and a new 126mm wheel could be done smoothly. It appears that the rear derailer has enough lateral movement to accommodate the slightly wider cassette in the rear.
Assuming that the above is not a wacky idea, the issue of building a 126mm OLD rear wheel is raised. I assume that if one looks hard enough, one can find an appropriate freehub -- might have to convert from ultraglide to hyperglide, but that is straightforward. But would it be worthwhile to convert a 130mm freehub to 126mm?
In an old thread people suggested removing a 4mm spacer on the nondrive side. But that would create more dish. Could one instead swap the 8/9/10 speed freehub body with a 7 speed and replace the axle to lose the 4mm? Would a modern Shimano hub have any advantages over an older 126mm hub?
Any comments or suggestions are appreciated. Thanks.