The stock wheel/tyre combo (195/55 R16) has a diameter of 24.44" or 620.90mm. The closest matches to this (with less than 1.1mm difference in overall diameter) are: 215/50 R16 (24.46" or 621.40mm) 210/45 R17 (24.44" or 620.80mm) 235/40 R17 (24.40" or 619.80mm) 205/40 R18 (24.46" or 621.20mm) For reference sake, the biggest difference lies between the stock tyres and the 235/40 R17's. With the speedometer calibrated for 195/55 R16's, replacing them with 235/40 R17's would result in the speedometer and odometer reading high by 0.18%. To give a practical example, the error would cause your speedo to read 100.2 km/h at an actual speed of 100 km/h, and your odometer would record 1001.8 km for every 1000 km actually travelled. Keeping the stock rims and using a 205/50 R16 tyre would drop the overall diameter to 24.07" or 611.40mm. This would result in the speedometer and odometer reading high by 1.55% (i.e. 101.6 km/h at 100 or 1015.5 km after 1000). A common "upgrade" seems to be to 215/50 R17's, which have an overall diameter of 25.46" or 646.68mm and therefore cause low readings by 4.0% (i.e. 96 km/h at 100, and 960km after 1000). Moving to 215/40 R18's will cause low readings by 1.32% (i.e 98.7 km/h at 100 and 986.8 km after 1000). Finally, the other size mentioned was 215/35 R18 - these will result in high readings by 2.17% (102.2 km/h at 100, 1021.7 km after 1000). As for scrubbing, this will be determined by different wheels' offsets as mentioned by others and your guard clearance. Different tyre widths are suited to different rim sizes, typically as follows: 195's suit wheel widths of 5.5-7 inches 205's suit wheel widths of 5.5-7.5 inches 215's suit wheel widths of 6-7.5 inches 225's suit wheel widths of 6-8 inches 235's suit wheel widths of 6.5-8.5 inches Hope this all helps.