Is a gummed-up freewheel salvageable?

I have the same problem, even though I never flipped the wheel to run single speed. It’s not worth the effort to try to open it up, even if possible, because it is so cheap. I would think the “ratcheting” mechanism is stuck in one position and the springs are rusted. Perhaps the answer is to throw it in mineral spirits for a month to see if that unsticks it. If it does, then you might want to put it in used motor oil for another month to lube it.

@Phatboing 110339 wrote:

I was going to ride the studly singlespeed this morning, but discovered that the freewheel has lost some of its freedom – no doubt from the combination of icy rain/road gunk/who knows what – and is more of a fixed cog that runs away on its own when it likes.

I didn’t really examine the thing, choosing the ultimately more appropriate MTB, but it’d be really obnoxious if this was the end of the freewheel. Can I salvage this with grease somehow?

Totally fixable! depending on how bad it’s frozen, either take a can of WD-40 or brake cleaner to it while freewheeling it (off the bike, so as not to degrease the hub bearings, too) – then drizzle some Phil’s Tenacious oil around the gap between the fixed part of the freewheel and the freewheeling part of the freewheel. be liberal with the Phil’s. Otherwise, you can attempt to disassemble the freewheel with a pin spanner while it’s gripped in a bench vise. But be careful because there’s about 394 teeny tiny ball bearings in there!