[Nonfractal]

Scaleauto cars?
Looking on retailer websites, scaleauto use two sizes of spur gear for their 3/32 axles
15.8 mm 17mm
To replace either of these with another manufacturer's gears, you will have to closely match the diameters. 

however, in a new car, it is likely that the gears have been assembled in a slapdash way at the factory.
Disassembly and careful reassembly , especially paying attention to the backlash, run-in and lubrication, will bring quieter running gears.

Have a look at thread "gearing explained" if you really want to dive deep down that rabbit hole. 
https://slotracer.online/community/showt...=Explained
AlanW




Scaleauto 1/32 anglewinder Procomp RS nylon crown gear 28t (Yellow).

• For 3/32" (2,38mm) axle
  
  
• Black aluminium insert
  
  
• M2.5 screw
  
  
• Outside diameter: 15.8mm