The translator says:
Zahnrad means 'gear wheel'
And - which drives the chain: welches die Kette fährt
which drives the wheel is: welches das Rad fährt
I tried these back and forth many times to see if they come out both ways and they stay constant. When Zahnrad is combined into the phrases we get:
Zahnrad welches das Rad fährt = Gear wheel of which the wheel drives
and Zahnrad welches die Kette fährt = Gear wheel of which the chain drives
And 'Getriebe' seems to mean 'transmission' while 'Antriebe' also means 'drives'.
Okay, I thought you asked for the possible translations of the word "gear".
'The gear that drives the chain" - Der Kettenantrieb (in German you use more nouns than verbs)-
you could say: "Das Getriebe, das die Kette antreibt" but that would sound strange in my ears.
"the gear that drives the wheel" - Das Rädergetriebe (unless it's a car, then you just say "Getriebe")-
Again you could say "Das Getriebe, das das Rad antreibt" but that would sure be the Anglicism of the month.
"drive" and "gear" have the same meaning , therefore you would not translate them both.
"gear wheel" is something different, it's the same as a toothed wheel.
Well, "toothed wheel" means "Zahnrad".
Sorry I can't really help you.
"gear" can also mean "der Gang"
But I don't even know much about these things in German so how could I help you with the English words?!
Sorry