Chainring bolts sit in an awkward spot for wrenches. The nut on the backside of the chainring needs to stay put while you tighten the bolt from the front, but there's almost no clearance between the nut and the crank spider. Standard wrenches won't fit, and pliers just round things off. Park Tool's CNW-2 solves this with a slim profile designed specifically for the job—the wrench head is thin enough to slide into that tight space and engage the nut's slots without interfering with the surrounding chainring or spider.

The CNW-2 works with slotted chainring nuts, which remain the most common style on road and mountain cranksets. Two engagement pins on the wrench head drop into the nut's slots and hold it stationary while you drive the bolt from the opposite side with a 5mm hex wrench. The handle provides enough leverage to keep the nut from spinning, even when you're applying real torque to seat the bolt properly. Without a tool like this, you're left trying to jam a screwdriver into the slots at an angle or hoping friction alone holds the nut—neither approach works reliably.

This is one of those single-purpose tools that seems unnecessary until you actually need to install or remove chainring bolts. Shops keep several on hand because they're essential for crankset service. Home mechanics who do their own drivetrain work will reach for it every time they swap chainrings, replace worn bolts, or build up a new crankset. The stamped steel construction handles repeated use without bending, and the compact size means it fits easily in a tool roll or shop drawer without taking up much space.... Read More