micky wrote in
:

I finally bought the trailer hitch for my Solara and it came with
M10 -1.25 x 30mm bolts. So how come I need to use the 17mm socket
on a 10mm bolt?



There are two dimensions at work he
1) the bolt shaft, and
2) the bolt head.

The "10mm" refers to the diameter of the /shaft/ of the bolt.

The "17mm" refers to the flat-to-flat dimension of /head/ of the bolt.



--
Tegger