I recently picked up a super clean 2 X 8 speed Shimano 105 road bike. When on the the small front ring I get chain rub on the big ring when I'm in 7 or 8 on the rear ring. The whole bike looks original except for the seat. When I mentioned it to a friend he said some bikes you have to shift correctly and wont let you use both small rings.
Do I have a chain alignment issue, or do I need a shifting lesson?