Iibheringi ezihamba kumgca othe ngqo kumzila othe ngqo zezeebheringi ezicacileyo.Ukuthwala umgca kusetyenziselwa ukumisela indawo yentshukumo ehambelanayo ye-shaft ejikelezayo kunye nezinye iindawo, ukuxhasa okanye ukukhokela iindawo.Umsebenzi ophambili wokuthwala umgca kukuxhasa umzimba ojikelezayo womatshini ukunciphisa i-friction coefficient yomthwalo womatshini kwinkqubo yokuhanjiswa kwezixhobo.