Tamiya ta01/ta02 speed tuned gears.

[Mike145]

Hi, I'm sorting out my ta01 for the iconic cup at west london and Broxtowe. Got the speed tuned gears for it but not sure which to use with what pinion etc. Put simply I don't really understand how the gear ratios work to be honest. Can anyone put it in idiot terms for me or even help me out with spur/pinion combinations for the two tracks. Would really appreciate any help, thank you.