i have heard that you must remove the tire before welding on the rim. anybody know why?
i was thinking on using a mig on the rim.

 

If the part of the rim you are welding on does not touch the tire you should be ok if you weld for short periods and cool it back down quickly with a wet rag. Make sure there isn't any fix-a-flat in the tire either or you will probably die. Welding+Butane=Death. It is amazing I can figure that out but I still don't know what 2+2 equals.

 

thanks.
tire has never had fix a flat or any type of sealer in them.
butane + spark = boom