Roda nganggo griginuduhake pindah ing pinggiran transmisi meshing terus-terusan gerakan lan daya saka komponen mechanical, dening untu pindah, alur untu, pasuryan mburi, pasuryan normal, bunder ndhuwur waos, bunder ROOT waos, bunder dhasar, pamisah bunder lan liyane. bagean, kang digunakake digunakake ing transmisi mechanical lan kabeh lapangan mechanical.
Peran pindah utamane kanggo ngirim daya, bisa nransfer rotasi poros menyang poros liyane, kombinasi gear sing beda-beda bisa muter peran sing beda, bisa nyadari deceleration mekanik, wutah, owah-owahan arah lan tumindak mbalikke, utamane piranti mekanik yaiku ora bisa dipisahake saka gear.
Ana akeh jinis gear.Miturut klasifikasi poros gear, bisa dipérang dadi telung jinis: gear poros paralel, gear poros intersecting lan gear poros staggered.Antarane wong-wong mau, pindah poros paralel uga kalebu pindah spur, pindah heliks, pindah internal, rak lan rak heliks, etc.Gir poros intersecting duwe pindah bevel lurus, pindah bevel busur, gear bevel nul, etc.The gear poros staggered wis staggered poros heliks gear, worm gear, hypoid gear lan liya-liyane.