aluminium diamondback mtb, used for light touring. lots of rough
roads in se asia, usually about 20-25 pounds on the rear rack, in
addition to my 185.
after a cleaning following a particularly rough ride, noticed a deep scratch,
about 3" long running lengthwise, midway down one chainstay. closer inspection
found it to be a crack, with another crack on the opposite chainstay.
no dents, no accidents, nothing i can think of to cause this. all chainstay cracks
i've read about have been at the weld near the bottom bracket, unless caused
by auto accident.
should an aluminum frame wear out after three years and maybe 20k miles?