I think I went overboard on this build I put together for USGT 25.5

I used TRF 419 arms and installed DCJs in the front and CVDs in the rear.

Also the Hiro Seiko kit for the TA07 works great with the TT02

Anyone guess what I did yesterday?

You have connected your Multimeter wrong?
Illegal motor tuning?
A complete mess?

My TT02's first run.


She's not fast, but she's quick enough to be fun!

Aside from some 'wandering' off fully-trimmed steering, which is probably the result of play in the steering links, I'm very happy!

aluminium screws are nice... but that steel turnbuckles hurts really!

Its a cheap multimeter and the common port is broken. It still works the way its plugged in, but reads the inverse. Works for stuff like this.

I've read about water-dipping motors to wear in the brushes to the comm. But the water is only for the brushes, so I figured why dip the whole thing? Have some syringes I use for precision stuff, so I filled one with RO water, and the other with 99% Isopropanol Alcohol.

I actually compared this to a silver can that I just threw in and ran. The comm on that one is scored and nasssssty. Might try it on that one and post a before and after.

I run it on a single AA, and use Labelle 106 on the bushings. Couple drops of water on the comm and it starts to work its magic. As it starts to drag running voltage down follow with alcohol to clear the worn brush material. Repeat until the brushes are about 90% worn in, final squirt of alcohol followed by compressed air. re-lube bushings and run.

Wow. It feels smoother, maybe even more responsive I'd dare to say. Who knows, but it seems like a strong little motor.

And as for the final comment; Yes, a mess it is.

The water method is good for original silver can. The torque and sport tune have much softer brushes.. if you submerge them, they will be done for.. just a simple flash or squirt is enough to break them in

What is the largest 48p pinion that fits under cover before you have to cut it

Do you mean "spur" gear?
At the very least, the question you have posed cannot be answered without one or the other specified.....

Question. Saw the TT02 with all 419 arms. I am wondering if the Xray short arms will fit TT02. Or the stock TT02 arms handle better for rally/street run?

Yes within 30 seconds of adding the water to the brushes they wore in rather quickly, hence the alternating between water and alcohol.
Definitely a benefit to doing it but what I have read leads me to believe most who attempt it don't do it properly and get bad results.
But with it used widely in the RC scene many years ago says it did something lol.

spur is 66 48p

From what I have read, the largest 48P pinion gear you can use before it rubs on the inside of the stock gear cover is a 53T pinion.

I prefer 64P gears and my gearing is 75/51 that gives an FDR of 3.82 and post #3008 shows that I had to mod the stock gear cover to make clearance for the pinion. I later found a local guy who printed me a new cover that I have since installed.

Can I use universals in the rear of the car with the oil gear diff?

The main purpose of submerging a motor during a wet break-in is to subject the motor to significant drag, so the motor will have to work extremely hard for an extended period of time. The significant drag limits the motor's speed, which reduces the magnetic flux inside the can. The reduced magnetic flux is unable to generate as much inductive resistance in the armature coils as it normally would if the motor were spinning freely. The lower resistance allows the battery to push more amperage through the motor, and because that amperage is being pushed through a very tiny contact area between the brand-new brushes and the commutator, the contacting surfaces of the brushes get extremely hot and start to disintegrate. This accelerates the break-in process by an order of magnitude -- but it can also destroy soft brushes in a matter of seconds, as I and many other people have discovered over the years. A wet break-in is only useful (or safe) for motors with extremely hard brushes that would take an extremely long time to break-in without the continuous drag of running underwater. For brushed motors with softer brushes, a few full-throttle accelerations will put enough load on the motor to break-in the brushes, and then the commutator can be cleaned with electronics cleaner spray.

Regarding brush debris: Submerging the motor in water allows brush debris to be washed away instantly by the churning water inside the motor, whereas applying a few drops of water directly to the brushes just causes the debris to form a grinding paste that stays on the brushes. That's why the brushes broke-in so quickly for you. If it works, it works, but there's a significant risk of the brushes being damaged by so much abrasive material in such a small area.

(source for magnetic flux explanation: John Rob Holmes of Holmes Hobbies LLC)