Mechanical Brake Big problem

[Shark413]

Ok I have several brushless conversions and most of large scale (1/8) vehicles use mechanical brakes. I like the feel and ability to adjust the bias, plus the fact it seems to take some load off the electrical system. For a few months everything was cool, the buggies/truggies ran great, faster than nitro, gobs of torque and sweet brake action. Then it happened, I was checking the motors (Neu 15xx series) and found a lot of play in my ST-RR truggy. I contacted Neu and they said send it in. Got an e-mail a few days later saying the front bearing was shot and needed replacement because of excessive force on the shaft and is not covered under warranty. Yikees!! So I paid $$ and got my motor back a few days later. I believe the reason there was "Excessive force" on the shaft was because of my mechanical brake setup. I was using the Kyosho semi-metallic pads and precision rotors, which in my opinion are the best brakes. Unfortunately they are also very fat, the pads are very thick, so the motor needs to be set well back to clear the pads/rotor. This means the pinion rides on the end of the shaft, and multiplies the force placed on the front bearing. My 1/8 buggy has the same setup and the bearing felt ok. But because of what happened to my truggy I removed the rear brakes from both and went to a hybrid rear motor brake and front mechanical brake, since most braking is performed by the front brakes I felt this would be ok. I set the motor brake (Mamba Max) to 75% and took my truggy out on the track, right away I could see that there was way too much brake and I could no longer control the truggy in the air, the brakes were like an on/off switch. The track has this triple jump leading into a sharp 90 degree left turn, normally you hit the last jump nose down and get on the brakes. But that day the last jump was destroyed by previous drivers lawn darting it and it was a crater. I figured I would try a few more laps and try and get used to the brakes before I lowered the setting. Big mistake, I came in a little hot and over cooked the last jump, I applied brake and they totally locked when I landed, which normally with mechanical brakes would not be a problem, but immediately the truggy was make bad sounds. I pulled in and found that I had lost 3 teeth off the pinion. I believe this was from having the motor brake completely lock the motor and then the hard landing with such a heavy vehicle just put to much pressure on the drive train so some had to give (pinion). I know this is a long story, but this forum has a lot of very knowledgeable people who have passed on some good info. I just wanted to pass on my experience for those that may be thinking of using mechanical brakes.

Broken pinion, spur gear and diffs were fine.






Motor spaced 12-15mm from diff mount to clear brakes. Put a lot of stress on the front bearing.