FTX Vantage Reversing Direction of Drive Train

FTX Vantage: Reversing direction of drive train

When you want to upgrade to brushless electronics in your FTX Vantage car, it is good to note that before you can use a motor and ESCs with sensors, you must reverse the rotating direction of the drive train.

With the sensor technology you’ll get a better throttle response for the lower revolutions and a more accurate torque response. The motor transmits information on the precise position of the rotor when it is rotating on lower revolutions to the ESC, enabling the ESC to regulate current output more precisely, improving the power control.

When using motors with sensors, you must note that the rotating direction cannot be reversed the same way as in brushed motors and motors without sensors. Sensored Motors rotate in the opposite direction compared to regular motors. That’s why you have to reverse the drive train rotating direction for example in the cars of the FTX Vantage, Bugsta and Carnage series. It is not a difficult operation and it does not require special tools. You only need to turn over the differentials of the drive train inside the gearbox to reverse the rotating direction.

You’ll get the job done easily by following the steps below.

Tools needed for the project:
2.0 mm Allen wrench
1.5 mm Allen wrench
A work stand
Clean paper towels (e.g., kitchen paper)
E.g. a desk pad on which you can disassemble the car (to keep the working environment clean)
A container for the loose screws
Suitable grease for the joints and gears

• Start by removing the body and rear wing. If the tires are dirty, you can remove them as well to avoid spreading the dirt on the desk.

• To start the disassembly, remove the cover of the drive gears and the pinion gear from the motor. This allows the drive train to rotate freely.

Rear differential:

• To start the disassembly, unscrew the two rearmost screws from the bottom of the car, and loosen the screws in the front by about 3–4 mm but do not remove them.

• Next unscrew the two topmost screws on the gear box.

• To make the job easier, unscrew the shocks from the bottom ends.

• Unscrew all three screws of the rear suspension arm mount.

• To remove the mount, pull it backwards. Be careful when removing the mount so the hinge pins of the suspension arms don’t come off with it. If they come off, you can place them in the holes of the arm mount in the front. This way the suspension arms will stay put when you open the gearbox.

• You can remove the gearbox cover by pulling it backwards. You can easily access the differential once you’ve removed the cover.

• You can remove the differential by pulling it directly backwards. Once you’ve removed the diff, you can use the paper towel to remove grease from it and the inside of the cover of the gearbox.

• When you turn the differential, you should note that there are thin shims between the bearings and the diff itself that are used to adjust the gear mesh between the differential ring gear and the pinion gear of the drive shaft. When you turn over the differential, you have to move the shims to the other side.

- So, if there used to be three shims on the side of the gear and one on the side of the cup, you should switch their places so that there is one shim on the side of the gear and three on the side of the cup. When you have switched their places, you have to check the play of the gear once it’s put back into its place.

• Put the differential back in the gearbox with the gear on the opposite side to where it was. Turn the drive train on the main gear and make sure that the gear mesh between the diff and the pinion gear is ok. When you turn the drive train, it should turn without resistance from too tight gear mesh. Note, however, that there should be enough to fit a piece of paper between the gears.

• Next, grease the ring gear of the differential. You do not need to put a lot of grease on the gear, but enough to cover the whole gear. You can also grease the grooves of the differential (with e.g. Black Grease).

Next, close the gear box:

• Close the cover and tighten the two topmost screws
• Screw back in the suspension arm mount (all three screws)
• Tighten all four screws in the bottom
• Screw the shock absorbers back in

Front differential:

• Start by unscrewing the two screws in the bottom of the front bumper to remove it

• Next, remove the shocks to make the rest of the job easier.

• Unscrew the two screws in the front in the bottom of the gearbox and loosen the two rearmost screws by 3–4 mm.

• Unscrew the two topmost screws on the gearbox cover.

• Remove the suspension arm mount by unscrewing all three screws and pulling the mount off.

• This allows you to pull off the gear box cover.

• Clean the differential and switch the places of the shims as you did with the rear differential.

• Put the differential back to its place and check the gear mesh.

• Grease the ring gear of the differential and the grooves.
• Put the cover back to its place and tighten the topmost screws.
• Screw the suspension arm mounts back in (three screws).

• Tighten the four screws in the bottom of the gearbox.
• Finally, screw the bumper and the shocks back in.

-  After this, it’s important to check that the drive train rotates freely. Keep the car on the work stand and spin the rear tires to see if the front tires spin in the same direction. There should be no resistance when spinning the tires . If there is resistance, you can check the shims of the differentials. Too tight gear mesh will overload the motor and negatively affects the car’s performance and durability.

• Finally, put back the motor’s pinion gear, check the play between the
  pinion and the main gear and close the drive train covers. Now the car is ready for a test drive.