Editing Dustcap (section)

{{More citations needed|date=March 2023}}
A '''dustcap''' is a small [[Seal (mechanical)|cover]] used on the [[valve stem]] of a [[bicycle]] or [[car]] tire to prevent [[dust]] or other small [[particles]] from entering the valve and damaging it. Dustcaps are usually made from [[plastic]] but may occasionally be made of [[metal]]. The dustcap is internally threaded and is secured by screwing it onto the end of the stem. To prevent corrosion due to [[electrolysis]] and malfunction of the electronics in a [[direct TPMS]] and avoid costly repairs, metal valve caps without insulating plastic linings should not be used on direct-TPMS-equipped tire valve stems.<ref>{{Cite web |last=Markel |first=Andrew |date=2013-06-07 |title=TPMS Sensor Corrosion: 5 Tips To Help Avoid A Snapped Stem |url=https://www.underhoodservice.com/tpms-sensor-corrosion-5-tips-to-help-avoid-a-snapped-stem/ |access-date=2023-03-29 |website=UnderhoodService |language=en-US}}</ref>

A dustcap may also refer, on a bicycle, to the [[Crankset|crankarm]] bolt cover. It is usually a piece of metal or plastic that, on the crankarm, is snapped or screwed into the threaded [[counterbore]], which houses the bolt that holds the crankarm to its axle, the [[bottom bracket]] spindle. The dustcap serves to protect the threads (on the inside of the counterbore), which are used with a [[crankarm puller]] to remove the crankarm from the spindle.

A dustcap may also refer, on a bicycle, to the metal ring that covers the bearings in a cup-and-cone ball-bearing hubset.