what offset would i want for 17 inch rims with 205/40/17 tires? also could you give the suggested offsets for 16s with 205/40/16 and 15 with the the recommended tire size i forget what it is for 15s. any help will be appreciated.

For what car?

For a Civic:
17x7" 42-44mm offset 205/40x17"
16x7" 42-44mm offset 205/45x16"
16x7.5" 42-43mm offset 215/40x16" or 205/45x16"
15x7" 42mm offset 205/50x15" or 195/55x15"
15x6.5" 40-42mm offset 205/50x15" or 195/55x15"
15x6" forget what offset and 205/50x15" or 195/55x15"