I was given a old schwinn that I want to convert to a fixed gear. The only issue I have so far is with the crank. It has a ff system crank which means the free wheel is on the crank. I want to replace the crank but i'm not aware of a crank that can fit the bb. Any suggestion would help!! Thanks.

get a new BB, they are now terribly expensive. All city cranks are hot for the price.

take it to a store to find the bb size, threading, and perhaps find a ss crank if the preexisting crank is not good enough.

Just get a new BB that fits, try to get something with a spindle length of from 103-107. 107 will probably be cheaper and easier to find but you might have the run the chainring on the inside of the spider for a good chainline. Then get a crank that will fit the BB and that should be good. Be prepared to spend over $100 for all of this. Plus the $100 for a cheap wheelset, plus money for tools. You may need to buy a cog/lockring, etc. It isn't cheap to do a good conversion.

I was just looking at the BB and it isn't threaded its pressed so I don't know if that presents any more issues.

Many of the late seventies/early eighties Schwinn electro-forged bikes with the Shimano Front Freewheel System used Ashtabula one-piece cranks. You'll have to use an adapter like the TruVativ American to Euro BB-Shell Adapter] to use a 3-piece crankset with standard bottom bracket.

Mmhmm. New bottom bracket is a must man. I got a nice sealed cartridge Shimano 103mm BB at my LBS for $30. They're really easy to install, it's just kind of a gunky mess doing it because your old bracket is probably the "condom" type, rather than sealed cartridge. Either way, it's pretty important to get something good in there. 103mm is nice because it helps with chainline. I use a Sugino RD crank with the ring on the inside of the spider and my chainline is pretty darn close to perfect, I'm really happy with it. Have fun with it man!

i have a 71 schwinn super sport converted to fixed,with a 1pc. crankset,and it works just fine

I had to mess with the converter on a build and trust me its not worth it. By the time you buy the converter you could have found a cheap bike to use from goodwill or a flee market or even a garage sale.

That is completely different from a Front Freewheeling system. An FF bike might make a decent single speed, but converting it to fixed gear is probably more trouble than it's worth. Especially since the FF system came on lower-end bikes.

Yeah I think the only way is with the truvative BB converter. Does anyone know anything about Tec-9 cranksets or Pake cranksets?

is the truvative converter the only solution? curious to know since i have an unfinished project bike with the FF system. i stopped when it became cheaper to just buy a complete bike from ebay instead. but i hope to someday finish it for fun

you may be able to sell the FF if it still works. there are folks out there restoring old schwinns and the FF system is one of the harder parts for them to find

Could you just use the bottom bracket and 1 pc cranks/chainwheel from an old (or cheap) BMX bike?

Not sure how "nice" you wanted your conversion to be, but if you're stricly going after function, this would be a cheap and easy route to take.

I have read some stuff about using a 1 piece BMX crank but nothing to serious. Just people thinking it might work but I haven't found anyone who has done it yet. I think I am going to go with the BB converter that truvative makes. It will create less headache down the road I think. I'm not sure how many teeth BMX cranks have on them but it seems like its less then I would want for a good fixie ratio.