Zoben da jujjuya jikin yumbu an yi su ne da kayan yumbu, gami da zirconia (ZrO2), silicon nitride (Si3N4) da silicon carbide (Sic). Mai riƙewa an yi shi da polytetrafluoroethylene, nailan 66, polyetherimide, zirconia, silicon nitride, bakin karfe ko aluminum na jirgin sama na musamman, don haka yana faɗaɗa saman aikace-aikacen yumbu bearings.