freewheel
 

I have a bike with the freewheel in the bottom bracket, not at the rear hub. It feels like it's stripped, cranking with any real force cause the cranks to just slip right through, and not drive the bike. Can this be fixed? I'm totally unfamiliar with this type of freewheel, wondering how to replace it if necessary.

This is called front freewheel and while uncommon is still serviceable.

These systems are fairly robust, and rarely fail with parts breaking. Most of the time, rust, dried grease, or dirt are interfering with the action of the ratchet mechanism causing it not to engage solidly. Often you don't even need to disassemble, but can get by squirting in some solvent, working the mechanism to clean the insides, then flushing it out. Follow that by a rinse, dry and fresh oil and there's a decent chance that it'll function like new. The hardest part of the job being cleaning up afterward.

If all else fails you can replace it with a conventional rear freewheel system, but this involves some pricey parts - new crank and bottom bracket, and new rear wheel - and so is only worthwhile if you have used parts to transfer, or buy a used or crashed bike at a yard sale for the parts needed.

Just out of curiosity, what kind of bicycle do you have? i have heard of these front freewheels on one or two models of old Schwinns. I THINK they were on an old version of the Caliente?

Anyway, they are pretty rare and pretty cool.

+1

I still ride my 79 Caliente and love it.

Easy enough to remove the crank to inspect and clean.

My biggest problem is that it has the Shimano Postiron ll and needs a special cable and housing ( push/pull ) for the RD.
( heck, the original Postiron had 2 pull/pull cables to RD ! )

Enjoy the looks I get when stopped at a light and my chain just keeps on a truckin'.