Ok this is stupid. I keep seeing reference to the hex bolts common to Sugino 75 BB/crank setups being 15mm. Do they seriously use a huge 15mm hex wrench for those bolts or am I reading this wrong? Anyone who has them on their bikes want to chime in and let me know? I only ask because I haven't even seen a 15mm hex wrench around here and photos of the BB/crank setups I've seen don't look like the head is that big.

The biggest I've seen are 10mm hex bolts holding the crank arms on my Shimano XT setup..

crank bolt is standard 8mm. chainring bolts are standard 5mm.

This is why I love this place. Thank you.

the 15mm size is not hex, they are the size of crank bolts with heads for socket wrenches.

usually when it says hex and then 15mm it means it's a regular six point 15mm bolt head...six point being the hex shape...i have some crank bolts on my bike that are 14mm hex.
not 14mm allen, that would be effing huge.

external vs. internal hex, that's easier.