specbolt main specbolt store specbolt products about specbolt Team Specbolt Racers Favorite Specbolt links Contact Specbolt
To order or ask about specific Motorcycle or ATV bolt kits you can call us anytime at 770-363-6580.

This is where we will teach you all about fasteners. Everything from properly measuring a bolt to the different head styles and grade ratings system of metric fasteners. This information can come in handy when you are trying to order a certain size bolt. Giving us the correct size ensures that we send you the right size.


To measure a flange bolt's length ( l ) measure from the bottom of the head to the end of the bolt. This measurement is in mm.

To measure a Hex or flange bolt's diameter ( d ) measure across the thread of the bolt. This measurement is also in mm.



The common metric thread pitch for motorcycle and ATV uses are M4-.7, M5-.8, M6-1.0, M8-1.25, M10-1.5, M12-1.75, M14-2.0 and M16-2.0. Where the first number indicates the shank size in mm, the second number indicates the thread pitch in mm.

For example M10-1.50 indicates a 10mm thread diameter with the spacing between the adjacent "peaks" of the threads = 1.50 mm.

Typically a metric bolt's size is stated like this....

M(d/diameter)-pitch x(l/length)

For example if a bolt's diameter is 8mm with a pitch of 1.25 and a length of 25mm.

The bolt size is a M8-1.25x25



Specbolt uses 10.9 grade which meets and usually exceeds motorcycle and ATV manufacturer's specs.

If we want to approximately compare metric grades to U.S. grades, a metric 8.8 is roughly equivalent to a Grade 5. Grade 10.9 is roughly equal to a Grade 8; and 12.9 is roughly equal to a Grade 9. Metric nuts are marked with a single or double numerical symbol (8, 10 or 12). Always match bolts and nuts of comparable grades (use a Grade 8 nut with a Grade 8 bolt; use a metric grade 10 nut with a 10.9 grade bolt, etc.). When dealing with metric fasteners, the 8.8 bolts are similar to a Grade 5. If you need higher tensile strength in metric, stick to 10.9 or 12.9.

The higher the first number, the stronger the bolt in terms of tensile strength. The higher the second number, the longer it will take to enter the yield point.

Note: Metric steel bolts are only required to show a grade mark if they are 6mm and larger and/or are Grade 8.8 or higher. Nuts must be grade labeled if they are Grade 8 or higher.


To ask us about a specific ATV or Motorcycle bolt kit email direct to specbolt@gmail.com or call us anytime at 770-363-6580.

Specbolt's Suzuki kits Specbolt's KTM kits Specbolt's Honda kits Specbolt's Kawasaki kits Specbolt's Yamaha kits