I need help making new spur/pinion gear options.

[RC youngin]

My cc-01 finally works. I'm giving it to my brother for Christmas. But, I'm also borrowing it to do a project for my physics class dealing with how changing gear ratios in a transmission changes torque and top speed. I'm using a trailer that I built to tow various weights and timing how long it takes to travel X distance. this car has been "heck". I had to hand build both sets of body mounts, installed 2 motors cause the first got too hot, 2nd works great, custom fitted a Newbright jeep body, made LED headlights, hand made a servo horn and clevis thing, re-programed ESC, bought flysky gt3b TRX & RX, changed battery from 7 cell to 6, rebuilt entire rear axle, greased EVERYTHING, fixed rear left shock. I think thats it.
My problem is that in order to do the testing, I need at least 3 different gears, including stock. My question is what gears should i change, where to get them/how to make them work, and what tooth #'s to get.
please help.

[RC youngin]

By the way, This entire project is due on the 9th of january, so, there's a bit of urgency.

[m1009cucv]

there is only 2 different pinion sizes you can use.. 16 and 20 i think

[Honchoforever1]

There's no different size spur gear for the cc-01. And there's only two different pinions 16 & 20.

[Honchoforever1]

But you cAn use a gear reduction unit to change ratios.

[greggreg2011]

all the above,,,no spur but if your really handy you can make 1 and yes only 2 pinion options,,,,you can make a 3rd pinion option by figuring the mounting spot and adding the 2 new motor mounting holes