HEADSET SPARES LOCKNUT 1" THREADED 21.1MM I.D. CHROME
$5.00
By BMX Life
Great if you damage or lose yours - BUT - The main reason we sell individually these is different.
If you have a 1" threaded fork with internal diameter of 22.2mm, and your stem is 21.1mm you will experience rocking and movement at the top of the headset. This is annoying and can lead to damage or failure of parts.
Most people either seek to find a matching stem in 22.2 or SHIM the stem to make up the difference. The latter can be tedious and messy work.
By installing a 21.1mm Locknut on your existing setup, you can stop the movement at the highest point of the headset, hence solving the problem easily and invisibly.