What is the purpose of a rim nut?

The rim nut fixes the valve in the rim. Some regard it as unnecessary. And indeed, you may well ride your bicycle without a rim nut. It is however helpful when attaching the pump connector, as particularly when the pressure is low the valve may fall inside the rim. With some rims there may be a rattle if the valve is not fixed.
The use of a rim nut also prevents unwanted movement around the valve, which can prevent valve tear off damage.

The rim nut must only be tightened by hand. Never tighten the rim nut with pliers, as this can lead to tube damage.

Updated on: 03/25/2025