Size of Rims

i want to know what's the biggest size of rims you can fit on a 1995 buick rivera. i was thinking of some 20s but don't know if they fit. if any one can send me some info it would be much appreciated.

Ok man ill tell ya i have a 98 buick rivi and you should be able to fit 22s with low pros though real tight fit but looks good peace....