As long as you've got a modest 3.6+mm between the outer face of the small cog and the inside of the dropout, the 7-speed freewheel should be fine if you use any modern 8-speed compatible narrow chain. A few frames will challenge these clearance limits with an inward-protruding seatstay atop the dropout, but most are adequately clearanced.
For a quick check, I usually just lay a 4mm allen key against the small cog and observe the distance to the outer face of the drive-side locknut.
Many bikes from the 5-speed era left huge clearances outboard of the small cog, big enough in some cases to allow the chain to fall to the axle. What were they thinking?
> I'm looking for drop bars, aluminum, 26.0 clamp
> diameter, without clamp knurling, or with knurling no
> greater than 32 mm in width. I've got a Cinelli 64-40
> that I can get in the stem, but I've got a fair amount
> of knurling exposed on either side, and I'd prefer
> something rather cleaner in appearance. The eBay fare
> (the Ambrosio Champion bars for example) have a
> knurling 40 mm wide (I asked one seller). Does anyone
> have something in their inventory that they would
> consider selling that would be appropriate for a bike
> built in the late '50s to early '60s? I'll use the
> Cinelli if I have to and wait for something better to
> come around, but I'd like to get this polished off if
> I could. The bar is the nly thing left to do on the
> On another note, One of my frames has a rear spacing
> that's 120 mm, but I was able to get a seven speed
> freewheel to fit in the frame. From what I've read
> this should not be feasible. The back end hasn't been
> 'adjusted' in any way and reads 120 mm quite
> accurately. What bad thing could happen with this
> apparent mismatch? I'm asking because I have a five
> speed freewheel in hand and am contemplating replacing
> the seven speed freewheel with it. I'd expect to have
> to have the rear wheel re-dished, as when I had the
> wheelset built for the Frejus the builder specifically
> asked what speed freewheel I was going to use in order
> to dish the wheel properly.
> Scott Baxter