ftermarket wheel/tire options
Diameter: Wheel diameters from 16"-20" will fit on the Mazda6 and wheel diameters 17"-20" will fit on the MS6. You might be able to go 1" smaller and larger but it is not recommended.
Width: Wheel widths from 6.5"-8" will fit on both Mazda6 and MS6.
Offset: The offset that will work depends on wheel width and tire size. To compare the offset difference between wheels of different width, use this offset calculator. However, even though the final outer rim location of two wheels may be the same, a tire mounted on each rim will stick out differenty. For example, a 225 series tire may stick out 17.5mm from the rim of a 7.5" wheel while the same tire may stick out 24mm on a 7" rim. That extra 6.5mm could mean the difference between rubbing and not rubbing. Here is a summary of the offsets I have seen work for other Mazda6 owners:
7 inch wheel with up to 215 tires: 38-60mm offset
7 inch wheel with up to 225 tires: 42-60mm offset
7.5 inch wheel with up to 215 tires: 42-55mm offset
7.5 inch wheel with up to 225 tires: 48-55mm offset
8 inch wheel with 215 tires: 45-50mm offset
8 inch wheel with up to 225 tires: 50mm offset
Note: 235 tires are not recommended for any wheel size unless you are willing to roll and/or pull the fenders.
Note: Whenever you are at the low end of offset specrum you may have rubbing under heavy weight conditions (full trunk and passengers). If you are concerned about this and do not want to roll fenders stay in the in the middle of the range. For example, some people claim the RX-8 wheels rub (18x8+50mm) with 225/40R18 while others say it doesn't.
