Iimpawu zegiya eziphilileyo:
1. Xa ukhwela igiya ezimbini zangaphandle, ukujikeleza kwenzeka kwelinye icala, xa kunyibilika igiya yangaphakathi ene-gear yangaphandle ivela kwicala elinye.
2. Inkathalo kufuneka ithathwe ngokubhekisele kwinani lamazinyo kwigiya nganye xa inyibilika enkulu (ngaphakathi) yegiya encinci (yangaphandle), kuba iindidi ezintathu zokuphazamiseka zinokwenzeka.
3. Ngokwesiqhelo iigiya zangaphakathi ziqhutywa ziigiya zangaphandle
I-4. Ivumela uyilo lwe-compact lomatshini
Ukusetyenziswa kweegiya zangaphakathi:Iplanethi yeplanethi yeplani ye-gear yenqanaba lokupheliswa okuphezulu, i-stutcheches njl.