Dear Jerry:
The Shimano may be wider than the Atom, but don't forget using a 16 instead of a 14 tooth small cog lifts the chain up higher, and therefore closer to the seatstay which is slanting in as it moves from drop out to seatlug.
The only fix I can think of is to respace the rear hub to 122mm or so by ad ding a washer or two, so as to splay the seatstay out a tad more away from the new chainline. Good luck.
Tom Adams Manahttan, KS, USA
--- On Sat, 8/23/08, Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net> wrot e:
From: Jerome & Elizabeth Moos <jerrymoos@sbcglobal.net> Subject: [CR]Freewheel Spacing?? To: "Classic Rendezvous" <classicrendezvous@bikelist.org> Date: Saturday, August 23, 2008, 9:39 AM
Recently ordered a custom 16-34 Shimano 5 speed FW from Loose Screws for my 1972 Follis 172, as I intended to commute on it with a fairly heavy large laptop in the pannier, and one short but steep hill on the way to work. The FW arriv ed yesterday.
But when installed the Shimano FW in place of the 14-28 Atom, the chain rubbed the seatstay when on the small cog. This is a newer Chinese made FW body, with a mix of new and NOS cogs. It appears the Shimano is simply wid er than the Atom. The lip behind the inner cog that butts against the hub she ll doesn't seem much different, so I think ether the cogs are thicker, or the spacers thicker, or both. Probably more the spacers, as the cogs cannot be too much thicker and still accept 3/32 chain.
Both the Atom and Shimano are supposedly "normal" 5 speed spacing, but the Shimano is quite obviously wider. Has anyone else observed signifi cant variation in the actual spacing of FW's of different brands? There were of course the SunTour Ultras and narrow spaced FW's from other manufacturers, but it appears even "normal" spaced FW's varied a lot. Was Shimano notorious for having wider spacing than others?
Did most manufacturers use the same spacers for "normal" 5-speed as for "normal" 6 speed, or was even the "normal" 6 speed spacing a bit narrower than 5 speed? Are there thinner spacers that will f it a Shimano 5 speed FW?
Regards,
Jerry Moos
Big Spring, Texas, USA