Abaqhubi abaninzi abatsha abasandula ukuthengaibhayisekile yentabaAndazi umahluko phakathi kwesantya esingama-21, isantya esingama-24, kunye nesantya esingama-27. Okanye yazi nje ukuba isantya esingama-21 yi-3X7, isantya esingama-24 yi-3X8, kwaye isantya esingama-27 yi-3X9. Kwakhona umntu ubuze ukuba ibhayisekile yentaba enesantya esingama-24 ikhawuleza kunebhayisekile enesantya esingama-27. Enyanisweni, umlinganiselo wesantya unika abakhweli amathuba amaninzi okukhetha. Isantya sixhomekeke kumandla emilenze yomkhweli, ukunyamezela kunye nezakhono zakhe. Ukuba nje unamandla amakhulu, isantya esingama-21 asicothi kunebhayisekile enesantya esingama-24! Zingaphi iimayile onokuzikhwela ibhayisekile yentaba?
Ngokwethiyori, kwisantya esifanayo sokuhamba ngeenyawo, ibhayisekile enesantya esingama-27 iya kubaleka ngokukhawuleza kunebhayisekile enesantya esingama-24. Kodwa eneneni, xa kukho umlinganiselo ophezulu wegiya, isantya sokuhamba ngeenyawo siya kuba nzima kakhulu, kwaye isantya siya kwehla ngokwemvelo. Ukuba isantya siya kwehla, isantya siya kwehla ngokwemvelo. Ngamanye amaxesha abanye abaqalayo bathenga iibhayisekile zeentaba bathi, “Ibhayisekile yam ilungile, kutheni kunzima kangaka ukuyihamba ngeenyawo?” Isizathu kukuba akazange akhethe umlinganiselo wegiya ofanele yena xa ekhwela.

Okokuqala masijonge umahluko phakathi kwesantya sama-21, isantya sama-24 kunye nesantya sama-27:

Ivili le-chainwheel kunye ne-crank ezinesantya esingama-21 48-38-28 ivili elijikelezayo 14~ 28

Ivili le-chainwheel kunye ne-crank ezinesantya esingama-24 42-32-22 ivili elijikelezayo 11~ 30(11~ 32)

Ivili le-chainwheel kunye ne-crank ezinesantya esingama-27 44-32-22 ivili elijikelezayo 11~ 30(11~ 32)

Umlinganiselo wegiya linani legiya elahlulwe ngenani lamavili ajikelezayo

Umlinganiselo wegiya ophezulu wesantya esingama-21 yi-3.43, umlinganiselo wegiya omncinci yi-1

Umlinganiselo wegiya ophezulu wesantya esingama-24 yi-3.82, umlinganiselo wegiya omncinci yi-0.73 (0.69)

Umlinganiselo wegiya ophezulu wesantya esingama-27 4, umlinganiselo wegiya omncinci 0.73 (0.69)

Ukusuka koku sinokubona umahluko phakathi kwazo. I-27-speed kunye ne-24-speed zine-gear ratio enkulu okanye encinci kune-21-speed, enokukwenza uqhube ngokukhawuleza kwaye ikwenze uqhube kancinci. Ngenxa yokuba i-chainwheel ene-speed ezingama-24 ayifani ne-21-speed, i-chainwheel encinci inokufumana i-gear ratio elula, nto leyo eyinzuzo enkulu xa ukhwela. Ibhayisekile ene-speed ezingama-24 inokufikelela kwi-transmission ratio ye-1.07 nokuba isebenzisa i-2X1 speed ratio. Ukuba i-flywheel yi-11~32, inokufikelela kwi-transmission ratio ye-1 (umlinganiselo omncinci we-transmission we-21-speed yi-1). Ngoko ke inzuzo ngaphezu kwebhayisekile ene-speed ezingama-21 ye-24-speed ayikho kwi-gear ekhawulezayo kuphela, kodwa ikwi-gear ecothayo, nto leyo eyenza kube lula kwaye kube namandla ngakumbi kuwe ukukhwela kwiindlela zeentaba. Umkhweli omtsha ucinga kuphela ukuba ibhayisekile ene-speed ezingama-24 ikhawuleza kunebhayisekile ene-speed ezingama-21. Mhlawumbi bambalwa abantu abahlulahlula inani lamazinyo e-crank kunye ne-cassette nganye ukuze babone ukuba yintoni umahluko.

Ngokuphathelele ibhayisekile yasezintabeni enesantya esingama-27, ivili layo elijikelezayo lifana nelenesantya esingama-24. Umahluko kukuba i-crank enkulu engaphambili ihlengahlengiswa ukusuka kwi-42 ukuya kwi-44, efanelekileyo kubantu abanamandla omzimba. Ibhayisekile yasezintabeni enesantya esingama-24 okanye ibhayisekile yasezintabeni enesantya esingama-27 ngumahluko phakathi kweendawo ezahlukeneyo zebhayisekile eziphuculweyo ukuya kwiimodeli ezingcono ngomgangatho wazo.