Wheel/Tire Size Calculators
http://www.willtheyfit.com/ - Compare current setup to new setup. Useful for us 4Matic guys who need front and rear outer diameters to be the same (mine are staggered... I do front wheel in "current" and rear wheel in "new" and it compares the sizes between the two)
http://www.1010tires.com/Tools/Wheel-Offset-Calculator - Name says it all... useful for comparing offsets. I can see this being useful if you measure the OEM fender-to-wheel distance (and wheel-to-strut distance), then using this to see if your new setup might rub.
https://tiresize.com/wheel-offset-calculator/ - Similar to the previous; a little less-intuitive but better visuals, IMO. Unlike the previous, it also takes tire size into account.
https://tyrestretch.com - For the adventurous, you can see how your stretched tires look on actual wheels. I couldn't find my specs on there, so it doesn't help me, but it's cool anyway. Might take pics of mine in the spring and throw post up. Someone could maybe even get wheel ideas from there.


