I'm not really sure what they mean though?
So if it says:
Current Wheel Width inches Current Wheel Offset mm

New Wheel Width inches New Wheel Offset mm
current 8" wide and +40mm
new 8.5" wide and +26mm
Rim Inner Edge Position: 8mm more (rim clearance to the strut housing)
Rim Outer Edge Position: Extended an extra 20 mm (position of outer edge of the rim)
So this means that it will hit the inner strut and if i had 8 mm more (26+8 = 34mm) it would be fine?
1 millimeter = 0.0393700787 inches, about 1/3 of an inch
Does this also mean my wheels will be sticking out 20mm from the fender?
.7 inches further out to the fender from original.
Sorry a little new to this.