The following five speed SunTour freewheels in my possession have non-symmetrical tooth profiles on the large splined cogs, with the tooth profile's straight side facing outboard (towards the derailleur) to facilitate chain pickup while shifting uphill to the larger cogs:
Perfect; Perfect 888; Winner; Winner Pro.
I don't have a ProCompe freewheel to check, but would be surprised if it was different due to extensive SunTour freewheel use and assemblage experience back in the day. Take a close look at the large splined cogs on your own SunTour freewheels. Photos supplied on request.
If you've assembled a SunTour freewheel without regard to the tooth profile on the large splined cogs, take a closer look and perhaps a re-assembly is in order. Putting the straight side of the cog outboard will quicken chain pickup while shifting up to large cogs, particularly under load.
Back in my weekend-only bike shop days, we assembled custom SunTour freewheels for fully loaded touring bikes and tandems, and minded this cog tooth profile, since tandeming and bike touring can involve upshifting to large cogs under heavy load.
Peter Brueggeman La Jolla California USA pbrueggeman(AT)ucsd.edu
Greg Weiner said: I could be wrong as I've never disassembled a Suntour freewheel, but... In my experience the larger 2 or 3 cogs on Suntour 5 speed freewheels have no profile...they're flat on either side. I can't see any reason why you wouldn't be able to use them flipped them over...
Peter Brueggeman said:Yes. No. If I have it right, the freewheel cog teeth have a profile and are not symmetrical. The straight side of the cog teeth faces outward towards the rear derailleur, to facilitate chain pickup when shifting onto larger cogs. If you turn them around, they will work but your upward shifting may/will suffer.
David Bean asks "...On 5 speed Suntour freewheels, are the two smallest cogs the only ones that are threaded? And the other [splined] ones can be flipped over in order to wear out the other side of the teeth?..."