# Bearing Sizing

Can someone clear up some confusion for me. The way I understand it, bearing sizes are listed in this order: inner diameter (ID) x outer diameter (OD) x width (W). A size C or SPEC bearing from YoYoFactory is listed with the following dimensions .250 x .500 x .187 (or 1/4" x 1/2" x 3/16").
But, a narrow C or a Half SPEC bearing is shown as .125 x .500 x .187 (or 1/8" x 1/2" x 3/16").

According to YYF dimensions, their narrow C bearing isn’t any narrower, it just as a smaller inner diameter. This, of course, can’t be correct, because it fits on the same axle as a regular C SPEC bearing. Shouldn’t the correct dimensions be .250 x .500 x .094?

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I think the half specs are actually a little more than half as thick. Maybe it’s supposed to be .250 x .500 x .125.

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I was just thinking the same thing myself. I have one in my yoyo at the office I’m going to measure tomorrow, but I just ordered a 5 pack of 1/4 x 1/2 x 1/8 (.125) on Amazon for \$8. If they work, I’ll be thrilled. I hate paying \$8 for a single bearing.

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Correct

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It’s called half spec… but more just to differentiate it from the full spec.

Calling it half spec was just a convenient way to identify it.

It is not ‘half’ the width.

Trust me on this>>> if it was actually ‘half’ .094; it would be hard to handle. And… that is why it is .125 and not .094.

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Yep, I understand that and it confirms what I was originally confused by. The size given for the Half SPEC bearing is actually wrong. It’s given as .125 x .500 x .187 when it’s actually .250 x .500 x .125. I thought I must be nuts because everywhere I see dimensions listed for that bearing, it’s the wrong dimensions. Just wanted to make sure I wasn’t crazy.

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There is a very very good chance that you ‘are’ crazy.

But that has nothing to do with questioning bearing measurements.

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That was funny.

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Yeah, there’s definitely some bad specifications that have been copied and pasted:

Both C bearings have an ID of 1/4" and an OD of 1/2".

The half spec is 1/8" (2/16") wide, the wide C is 3/16" wide.

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That cracked me up. Thanks for the smile.

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Huh I don’t really care about the bearing size I only care about the yoyo

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