Front disc brake spacing for thru axles

I have an Anvil Post Punk disc brake jig. I’m building my first thru axle fork. It’s a 15x100. The Post Punk was supplied with some small 3mm wide spacers that I vaguely remember Don saying were to be used when using the jig with a thru axle. He had a write-up on his website that explained it, but his website is gone and I can’t remember when to use them.

Is the spacing from the actual face of the dropout the same for all axle types? Are the spacers to account for the fact that the jig rests against the “hood” that helps locate the axle on a thru axle dropout?
The dropouts I’m using only have a 2mm wide hood, so I would need to use 2mm spacers, correct?

I tested my theory against a couple different Rockshox forks and things seemed to line up as long as the Post Punk was flush against the face of the dropout and not the hood. Easy enough to do on a Torque Cap style fork. I just want to make sure I’m understanding correctly.


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Hey, i think you will find the answer here :slight_smile:

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Thank you.
Not sure how I missed that. I did do a search first.

To answer my own question: the spacers are there to make up the distance between the face of the dropout where the axle contacts it and the hood where the jig will contact. In my case I need 2mm spacers for these particular dropouts.

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FWIW there is an archive of the Anvil website at

https://web.archive.org/web/20180327013021/http://anvilbikes.com/

-Jim G

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