Update - save yourself some headaches and use an 18t pinion as you can use the existing holes in the gearbox! See my newer video:    • Kyosho Raider 18 Tooth Pinion  Instal...   That being said, this video has some really good info on the different setups and is still worth watching before doing the mods.

Kyosho did us a bit dirty with the gear box in the Raider and Rocky. I wanted taller gearing to get some more speed out of my Turbo Raider as it would get up to its top speed really quickly but fell flat in its face on top end and left me underwhelmed with a 15 turn brushed motor and the stock 14 tooth pinion and 36 tooth idler gear. The car is really light (especially on a LIPO shorty) so I figured taller gearing would be not problem at all (plus I run it on pavement).

In this video I ended up doing some modifications to make a 17 tooth pinion fit in combination with a 32 tooth idler gear(now a 7.9 ratio down from the stock 10.8 as I calculated the transmission ratio as 4.2 and then just take the idler gear teeth divided by the pinion teeth and multiply this number by 4.2 to get the overall ratio) While many have complained about the stock gearing and lack of pinion options, I looked everywhere on the internet and couldn't find anyone that has put bigger than a 15 tooth pinion gear in so this was my solution.

Please note anything bigger than 15 tooth will not fit through the motor plate so you have to install the pinion from the top of the trans. It is easy to line up with the idler gear as you can see it. I ended up adjusting the mesh one final time as it was a little tight in the video. Using a thin utility knife to extend the adjustment slot didn't seem ideal in my mind at first but it worked really well (and I didn't want to fire up the Dremel with my family sleeping). That is also why I am so quiet in the video.... sorry if I am hard to hear. At night while my kids are sleeping is usually the only time I get to work on the car so I have to keep it down.

Below is the Turbo Rocky manual I mentioned in the video (page 7 and 29):

www.dirt-burners.com/rcdox/Manuals/Kyosho/Kit%20ma…

Last thing, that Futaba 112b speed controller - I might be wrong on the max motor your should run with it. The manual doesn't specify a certain number of turns but it seems 17 is the absolute max most people recommend and many say something more like 27 turns is more appropriate. 15 may fry it (especially with the taller gearing) but it is a risk I am willing to take!

Update: As you can see in my more recent videos of this car, it is faster (it did 28 mph) but it just does not have the torque it needs to get up to speed quickly. I was wrong thinking it would not really kill the acceleration but it did. It also gets the speed controller hotter that I would like so I am going to upgrade it to brushless to get all the torque I could want and then some and to have a setup that can handle the taller gearing.