bikes you should not buy.

If the cog is made of soft metal, (this applies to all production “fixies”) it will strip the threads off said rear wheel leaving the rider truly “brakeless” and the wheel unusable as fixed (unless you have a fixed-fixed flip hub).

  • surely if the cog is a soft metal it would strip the thread on the cog, still leave you brakeless - but the rear wheel would be ok?
    I’m no mechanic, but surely if the cog is a soft metal, it would strip/bend/break/wear faster, not the thread on the hub, non?

Either way you’ll be riding brakeless bmx style.
Also, cheap cogs have imprecise and sometimes less threads, both of which can strip your hub’s thread.