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Hi
I have all steel wheels on my various cars and I think I put 33 on the ones I had and as I bought newer covered hoppers they seem to sit higher for matching couplers. HOw do I measure car wheels to see if they are the same. Is there a guage to use or what?
Thanks
Bill
 

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use a micrometer to measure actual size ... for scale size [HO], just divide by 87 ..
33" wheels = actual 0.3793, 36" wheels = 0.4137 and so on ..
 

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if you don't have a micrometer, you can just use a ordinary ruler and cut out a piece of styrene or something firm
 

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With a ruler in place, and a small marker dot on the rim of the tire where you can see it, place the dot at BDC. Then roll the item until the dot returns to BDC. Note the point on the ruler where the dot is placed originally, and then note where it ends up at BDC again. That is the circumference.

Now, using Euclidian geometry, you divide the circumference by Pi, or 3.14159, and that should be your diameter.

A small digital or mechanical caliper would be faster...if you have one.
 
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