Depends on the hub. If the other side is one single thread diameter, yeah. If it has a "ledge" on the threads, please don't. Some hubs are "fix/fix," some are "SS/Fix," and I've never seen a "SS/SS" one but I suppose they might exist.
I might be totally wrong, but I think there might be more threads for the ss side than the fg side.
I was told by my local shop, it will work for some period of time. But in the long run it will probably fail.
in the long run we're all dead.
the cog side of a fixed/free hub will have less threads on the fixed side for the freewheel to engage on as it is step threaded and partially reverse threaded, but should still work.
free/free hubs do exist, primarily for BMX applications, but generally one side has a bit of a different diameter to run freewheels with less than 15 teeth
And if you don't believe me that it's OK, then listen to Sheldon. Don't f*&^ with the Sheldon.
Fixed/Free model can be used with 2 freewheels if desired.
I have run a freewheel on a fixed/fixed hub with no issues. Fixed/fixed hubs are the best when it comes to versatility.
and to the OP's question, I've done it in the past without any problems. Freewheels have significantly less forces at play with the hub threads compared to a fixed cog, so the threading (even if there isn't a ton) really isn't a problem.
i've been in the freewheel on the fixed side camp for several years. used it in races, mountain bike trails, loaded touring, no problems. everytime a shop employee told me that it was "wrong" i'd give a hearty guffaw and go order my parts online (which realistically i'd probably have done anyway).
now i am a part time shop employee, and i've seen three stripped fixed/fixed hubs that had freewheels on them. to be fair, they were stock on giant boweries (out of a probable twenty our shop has sold) and i don't think they were formula or dimension so maybe it's a hub quality issue.
Originally Posted by Sheldon Brown
my vote says yeah
how to tape your bars http://www.flickr.com/photos/89572419@N00/sets/72157629279270681/
I'm doing it with no problems yet. I asked the owner of my LBS what he thought and his response was "Have you ever heard of anyone having problems doing this?"
No. No I haven't. And neither has he.