Great Visual Calculator for Wheel/Tire/Spacer Influence on Tire Position
 

Don't know about you, but I learn best when I can see something - not just read numbers. Just found this calculator which takes wheel, spacer, and tire size, along with wheel offset, into consideration and then shows the position of the original tire compared to the new set-up.

Shows height and width of the old and new tire positions, both vertically and horizontally. Shows the change in proximity of the top of the tire to the fender well and the change in distance from suspension. Even shows the projected change in speedometer reading from old set-up to new.

For this bonehead, the visual is really helpful. To some of you this may be old hat, but for the rest I hope this helps you as much as it does me...

Wheel Offset Calculator

That's way useful, thanks!

Awesome resource, much appreciated!

Mods, this should be a sticky since it comes up so often.

I used this when I was looking at new wheels and tires. Extremely useful and gave me a great idea for tire comparison from stock, different size tires, and the offset. Like you mentioned, nice to see how how it impacts your speedometer as well. Great resource for sure!

That site is amazing. I'm the same way, need to see it as compared to reading numbers. Thanks for posting this!