This is a common happening. If area is just around the valve stem hole and the rest is solid you can clean the rust off, weld the valve stem hole and any other holes up (might have to gas weld because metal is usually very thin), and coat with an epoxy like JB Weld. This will let you use tubeless tires. Lastly, drill a new valve stem hole 180 degrees from the old hole in nice virgin metal.


Evan