Depends on the tire manufacturer. For example Dunlop 200/55 GPA DOTS are actually 191mm vs 188.5mm wide for 190/55's. Using your current tire as a reference either look-up its actual width or measure it. Then measure the distance between the tire and the closest interference point, typically the chain or the chain guard. Multiply that distance by 2 and add to the actual tire width - the result will be your answer minus a little for clearance.