bmw 316 i compac 96 reg - stering - mikomi 61

hi got a problum with the steering it tends to wander right an left an some times grabs the road iv been told a few things what it can be just like to be shor what the problum is be for i do any thing been told steering bushs it doz have over size wheels size 215/45/zr/17 inch on it dont think that will be a problem any help will be good thanks . colin