A bicycle rear frame includes a mandrel, a hub mounted on the mandrel, a
freewheel secured on the hub, two rear fork end members each mounted on
the mandrel and each formed with a first tapered face, two rear stays
each mounted on a respective rear fork end member, two press members each
mounted on the mandrel and each formed with a second tapered face rested
on the first tapered face of a respective rear fork end member, and two
locking nuts each screwed onto the mandrel and each rested on a
respective press member. Thus, the second tapered face of each of the
press members presses the first tapered face of the respective rear fork
end member to prevent the freewheel and the hub from being pulled forward
by the chain, thereby preventing the chain from becoming loosened.