7mm rod. It's the most common for bushings to slide onto
It is actually NOT 7 mm.
One of the common misnomers is using the size of the hole we drill to identify everything that goes with it. When you are drilling a 7 mm hole (.2756") and inserting a "7 mm tube" (OD=.2655", ID=.2455" ish) and it goes on an "A" mandrel, which Don says is .24409 (sounds right to me!!).
The difference between the mandrel OD and the 7 mm hole is significant (11.5 percent)
Wow, I am slowing down---2 guys post while I typed!!!