Aƙafafun ƙarfe na motawani ɓangare ne na ƙarfe mai siffar ganga, wanda aka ɗora a tsakiya na tayar da ke tallafawa tayar a cikin yanayinta. Wanda kuma aka sani da rim, rim, ƙafafun, ƙararrawa tayoyin. Cibiya bisa ga diamita, faɗi, hanyoyin ƙira, nau'ikan kayan aiki daban-daban. Girman cibiya a zahiri shine diamita na cibiya, sau da yawa muna jin mutane suna cewa cibiya mai inci 15, inci 16 irin wannan magana ce, wanda inci 15,16 yana nufin girman cibiya. Gabaɗaya a cikin mota, idan girman cibiya mai ƙafafu ya yi girma kuma rabon lebur na tayar ya yi yawa, zai iya taka rawa sosai ga hangen nesa, kuma kwanciyar hankali na sarrafa abin hawa zai ƙaru, amma sai akwai ƙarin matsalolin ƙaruwar amfani da mai. Akwai manyan sigogi da yawa a cikin injinan kera taya, a cikin sarrafawa dole ne a kula da sarrafa sigogi a cikin iyaka mai dacewa, in ba haka ba zai shafi tsarin da aikinTayar Rimin Karfe.