Gear case

{{Short description|Bicycle chain enclosure}}{{singlesource|date=December 2012}} {{nofootnotes|date=December 2012}} A '''gear case''', also known as a '''chain case''' or '''chain guard''', is a protective enclosure for the bicycle's chain and sprocket assemblies. Its primary function is to protect the cyclist from being soiled or trapped in the chain rings while also protecting the chain from dirt and moisture. Gear cases may fully or partially enclose the drivetrain and sometimes incorporate an oil bath for continuous lubrication. Modern examples are usually moulded in plastic. Although they are also used by some touring bicycles as well as some chain-drive machinery, chain cases are most frequently found on utility bicycles.

==History== From the 1880s until the 1970s, bicycle chain cases were typically made from metal or varnished cloth. These materials provided protection against dirt and damage, with metal cases offering greater durability but increased weight and production cost.<ref>{{cite web |title=Innovation and Sustainability - Cycling In Wageningen |url=https://www.cyclinginwageningen.nl/cycling-facilities/innovation-and-sustainability |website=Cycling In Wageningen |access-date=2025-08-24}}</ref><ref>{{cite web |title=Plastic kettingkast |url=https://logbankje.nl/?p=5342 |website=Logbankje | date=8 October 2016 |access-date=2025-08-24}}</ref><ref>{{cite web |title=100 jaar kettingkasten van De Woerd |url=http://www.rijwiel.net/de-woerd2n.htm |website=Rijwiel.net |access-date=2025-08-24}}</ref>

In the mid-20th century, Willemine Johanna van der Woerd (née Looijen), director of the De Woerd bicycle accessory factory, improved the design of cloth chain cases. On 25 July 1959, she filed a patent for a closure for a chain case in which the seam had alternating open hooks. A wire could be zigzagged through these hooks to close the case, providing a closure that was easy to open and close while remaining under proper tension. This design became the standard for varnished cloth chain cases and remains in use by Dutch bicycle makers today.<ref>{{cite web |title=De Woerd: geschiedenis |url=https://www.rijwiel.net/de-woerd_n.htm |website=Rijwiel.net |access-date=2025-08-24}}</ref>

In the late 1960s, van der Woerd introduced a plastic chain case. Together with technician Willem Gerritse, she has designed a one-piece chain case that was later optimized into a two-part design. In comparison to earlier cloth or metal cases, this innovation improved durability, simplified assembly, and decreased production costs.<ref>{{cite web |title=9 oer-Hollandse uitvindingen |url=https://mtsprout.nl/tech-innovatie/9-oer-hollandse-uitvindingen |website=MT/Sprout |date=15 April 2014 |access-date=2025-08-24}}</ref>

==Gallery== {{Gallery |width=240 |File:Popal Daily Dutch bicycle chain case.jpg|Fully enclosed cloth chain case on a Dutch bike |File:Close-up of plastic chain case on Bakfiets.nl.jpg|Modern fully enclosed plastic chain case |File:Bike chain guard full.JPG|Old-style fully enclosed plastic chain case imitating the cloth chain case |File:Bike chain guard part.JPG|Partially enclosed chain case |File:Flaming stack guard 1.jpg|Huffy Flaming Stack chain guard |File:Crank_Set.jpg|Crankset with an integrated chainguard bolted to the outside of the largest chainring }}

==See also== * Luggage carrier

==References== {{reflist}} * [http://sheldonbrown.com/gloss_ch.html#chaincase bicycle glossary entry for "Chain case"] from Sheldon Brown's website * [http://sheldonbrown.com/gloss_g.html#gearcase Sheldon Brown's bicycle glossary entry for "Gear case"] * [http://sheldonbrown.com/gloss_ch.html#chainguard Sheldon Brown's bicycle glossary entry for "Chainguard"]

Category:Bicycle parts