Mazda Talk Forums

Anyone know a web site with a good offset calculator? The one I found is confusing
MORE offset cause the tire center lines to create a wider or narrower track ?

IF you have 50mm offset wheels then 40mm offset is pushing the wheels OUT by 10mm.....and doing that on both sides of the car means you widen the track by 20mm. There are 25.4 mm per inch.

So, positive offset is from wheel hub mounting face IN toward the centerline of the car.
I needed to hear that from a reputable source because the online info I have seen just didn't quite make it "crystal clear". Thanks for that simplified explanation!

Easy way to remember,
"Smaller number, bigger track"

Imagine your wheels with rubber spokes. As you push the barrel/tire towards the center of the car, offset increases. As you pull the barrel/tire out, the offset decreases. Keep pulling, as the centerline of the barrel passes outside the plane of the mounting face of the wheel, offset goes negative. Deep-dish wheels have low to negative offset.

Got it ! Thanks all.

I use this:
http://www.1010tires.com/WheelOffsetCalculator.asp
and this:
http://www.1010tires.com/TireSizeCalculator.asp