njf690,
Perhaps this will help:
At least it's a visual guide for what you need to measure.
In addition to this, the Showwheels site offers this useful tip:
Wheels are 1 inch wider than the size suggests. For instance, an 18x7 is actually 8 inches wide overall. Width wise, to fit an 18x7 you will need 8 inches for the wheel plus tyre bulge. ekute, the inner guards have been pumped - it still scrapes though.
Unfortunately once you start modifying stuff it's a ripple effect.Stinky, this a huge lesson thath I am learning at the moment - I'm in the process of fitting triple webers to my 186 powered FC. I say process, as initially I thought it would be pretty straight forward, but the more I progress, I find more stuff that needs to be modified (or upgraded) to handle the power/induction increase. It never ends...
But it is mighty fun learning.
Kind regards,
Ol_Girl_58