Hi there,
last year, I purchased a shimano 5 speed freewheel, screwed it onto my
maillard hub, put the wheel in my 120mm spaced frame of my 'going to
the shops' bike and had a year of good fun on that bike. Not long ago,
I did the same thing (freewheel and chain were worn down), they ordered
the freewheel for me at the shimano distributor for the benelux.
However, great was my surprise to notice that now, (seemingly) the same
freewheel proved to be useless in the same 120mm spaced rear end. I did
some measuring and it turned out that the newer freewheel, although
having the same dimensions on the outside, had lesser thread! This
means that the freewheel sits further out towards the drive side drop
out and you cannot get the chain onto the smallest sprocket
anymore....I added some washers to the hub (I accept the risk (if there
is one), it's my own doing) and it works fine in an 126 mm spaced set
up (Now of course, I only wish I bought a Megarange 7speed freewheel,
or wouldnt that screw onto the maillard hub?).
It seemed worth to mention this (since for instance harris cyclery
lists those 5 speed freewheels as suited for 120 mm spacing), although
these things have become kinda obsolete now.
Maybe someone can shed some further light on this,
thanks anyway and pardon me for barging in like this.