Originally Posted by
1simplexnut
What about simplex ! no spring at all ! Those cunning french men
I believe that has a black plastic cylinder in the hole you can see in the dropout. Screw runs through that, Acts like thick grease or beeswax. And yes, in my experience with one bike, it works rather nicely. (I just wish those dropouts were longer. The chain had to be the perfect length to be able to use fix gear cogs 2 teeth apart without messing with it.)
Edit: I see from the post above that's a crescent, not a cylinder. Never looked at mine that closely. (They were on a trashed frame I bought for $20 to be a cheap, light fix gear. Fine scrutiny of the frame didn't happen until I discovered the cracks and then, the emphasis was on fixing them and watching for others. Subtle touches got missed.).