This is a Campagnolo carbon crank from the 5-arm era, but

there's a plastic part fitted onto the chainring bolts on the back of the crank arm,
which prevents any tool (Torx T30) from engaging with them.
I'm not sure what the intent behind this is, but normally
you can't remove the chainring bolts without destroying this part.


I made a tool a while back that can remove the chainring bolts
without destroying this part.


Got it off.


When you insert it into the chainring bolt hole

it clicks open and locks in place


↑It's a part like this, but



by shaping the tool tip this way

you can turn the bolt while avoiding the part.
Thanks to this, you can swap the chainring without leaving any evidence of loosening.


So there's no risk of anyone figuring out "this guy must've changed the chainring."