Ha Ha just had a Eureka moment.
A couple of weeks ago I was plagueing everybody about tyre offset. http://www.mr2roc.org/phpBB2/viewtopic.php?t=9999&highlight=offset But today I found a website that really makes it easy to understand. The Offset Calculactor http://www.1010tires.com/WheelOffsetCalculator.asp
Offset only really tells us whereabouts the Face/ Fixing plate of a wheel is in proportion to the rims center of balance. Its usually in mm so a positive offset of 45 means the face of the wheel is 45mm from the center of the rim.
Nearly All aftermarket wheels have a positive offset. This just means that the face of the wheel is closer to the outside edge of the wheel than the inside of the wheel.
Simple
Now it only really matters when we're changing wheels. and this is where it gets a bit more complicated. The standard wheels on the MR2 are 45 offset.
Most people are trying bigger wheel and therefore wider rims. So heres an example changing from a 6"front to a 7" rim.
Now first of all the extra inch means the wheel has grown by roughly 26mm(25.4 for those being pedantic). Now if my new wheels were also 45 offset it would mean the increase of 26mm would be split evenly. In otherwords the new wheel would be 13mm closer to the inside of the car as well as 13mm further out to the edge of the car.
(http://i56.photobucket.com/albums/g196/kjireland/offset.jpg)
Now every mm less than the original offset means that the face of the wheel is closer to the outside of the car
e.g. 6 inch wheel with 45 offset changed for a 7" with a 43 offset and then one with a 47 offset.
If the offset is 40 than the new wheel is 11mm further inside than the original wheel (13-2) while its 15mm further outside the car (13+2).
The 44 offset moves the wheel the other way now its 15mm further inside than the original wheel and only 13mm further outside.
Eureka
not quite
standard offset is 45mm
s:oops: :oops: s:oops: Edited, Thanks Mark