Originally Posted by
ottothecow
...what happens if this all blows up?
I'd never run on the street without a front brake just in case, but if this thing blows up is it just an issue of suddenly not being able to stop without a brake or does the chain do something nasty
Yes, the chain can very easily do "something nasty." If the cog starts to un-thread, the chain will come off, wrap around the hub, and lock the rear wheel up solidly. If, say, you were sprinting to turn in front of an oncoming semi approaching an intersection, you'd go down in the middle of the road and become road kill.