Classic & Vintage - Question about replacing a rear wheel..?

My current rear wheel is a 5 cog 27" by 1 x 1/4th. Is it possible to get a rear wheel with possibly 6, or maybe even 7 cogs? Or, do I need to stick with the 5 cog setup?

Your limitation isn't necessarily the wheel, but the spacing of your frame between the rear dropouts. It's likely 120mm if you currently have a 5-speed cluster. You can try to find a narrow 6-speed cluster (Shimano Ultra 6) or you can have a bike shop widen your rear spacing to 126 if you want to run a standard 6 or 130 if you want to run a 7-speed freewheel. To put those larger freewheels on your existing rear wheel will likely require a longer axle. This is the kind of work that a decent bike shop could do.

Neal

If I recall, six speed freewheels came in Ultra (same width as a five speed) and regular which was slightly wider and 7 speeds used the same spacing as an ultra 6 and were about as wide as a regular six with the extra gear. In theory you might be able to spring the frame out enough to slide a 7 speed in (it's 6mm wider which isn't much) but you might have a clearance problem between the small cog and the dropout, particularly if you have a claw style derailleur adapter with a nut on the back that protrudes a few millimeters behind the dropout. Like nlerner said, any decent bike shope should be able to cold set the frame to 126mm. "Decent" being the key work. There are many LBS's that will give you a blank stare and tell you they never hear of such a thing. But seek and ye shall find.

Suntour ultra 6 used 5-speed 120mm spacing. It became the 7/8 speed standard when rear spacing went to 126mm for standard 6-speed (read 5-speed plus one gear).

In other words. Go to a suntour ultra six freewheel running a 7/8 speed chain.

I wouldn't bother with 7 speeds.

Thats a good point, be sure to get the narrower chain (designed for 6-7-8 sp) if you go to the Ultra 6 cluster. Loose Screws has nice SRAM chains for fairly cheap.