Originally Posted by
Cridd
From what I have read, spur size is all where you want your motor, further back with smaller spur, further forward with larger. Sometimes a 69 is too small for a certain gearing so you have to go to 72 so pinion hits spur. But gearing ratio is gearing ratio, different spur is just changing motor placement by a few mil.
That makes sense but it seem like even though the spur gear doesn't effect the driving as much I find it hard to believe that all its for is a mm or 2mm of motor placement so can someone please elaborate more and the difference between a 69 tooth and a 72 tooth spur gear