# [V8] wheel offset calculator program

Jeremy Ward jward at mti-interactive.com
Fri Feb 4 00:17:42 EST 2005

```Hey gang.  I was asked some really difficult math by someone who read my
post and actually thought I understood the fine art of offset.  8-|
Yikes, does he know I failed calculus 2 times?!? (they always say that
the 3rd time is the charm)

In checking my answer (to see if I actually new what I was talking
about) I found the following calculator:
http://toy4two.home.mindspring.com/offset.html

It's pretty straight forward when the width stays the same, but if it
changes you must split the width difference in two, convert to metric,
apply to offset...  A lot easier to just use the offset calculator.  :-)

Another good resource is this explanation of what offset is:
http://www.tirerack.com/wheels/tech/offset.jsp

Oooh, and a nice tire calculator:
http://toy4two.home.mindspring.com/tire.html

So, for those who liked story problems in math class...  If my V8 has an
ET35 offset on a 17x7.5 rim, and I upsize to a 18x8 ET45 rim, how big of
a spacer do I need to keep the inside edge of the rim in the same spot
so it still clears the tie rod?

Answer:
8" - 7.5" = .5"
divide .5" by 2 = .25"
now convert .25" to metric = 6.35mm
Now add 6.35mm to the difference between 45mm and 35mm = 16.35mm

Same answer as the calculator above gave (16mm).  Make sense?

Of course the method I used on my V8 was to mount the wrong-offset
wheel, say 'wow that looks stupid', grab a tape measure, figure out what
would just barely tuck them under the arched fender w/o rubbing, and
order the spacers!  :-)

Cheers,

- Jeremy
```

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