==38.1mm frame (from 8020 Inc.)==

This frame is pre-punched with 21/64 inch holes which are intended for 5/16 inch hardware.  Equivalent metric hardware is listed below:

1 Bolt: 5/16 inch x 2.5 inch ~ M8x60<br>
2 Bolt: 5/16 inch x 4 inch ~ M8x100<br>
3 Bolt: 5/16 inch x 5.5 inch ~ M8x140<br>