Brushless upgrade

[Bjorn]

I just put a brushless esc and motor in my hammers, way too much speed! Well, I love it, but not so hot for crawling, love the torque but a little too much. My fault, 4000kv motor on a 70a esc. Any suggestions would be greatly appreciated on toning it down a bit. I'm still running the factory 76t spur and 28t pinion. What would be a better combo?

[Bjorn]

I will say, it was fascinating see the rig more than 5 times faster than the old 15 turn dynamite, and then put my 3s battery in, and it went to ludicrous speed for sure!

[meatmonkey]

You can gear it down for less speed. Going with a smaller pinion gear, such as a 21 tooth will slow it down. I'm not sure at what point you need a larger spur to allow the gears to mesh, as there is only so much room to slide the motor in the mount. I do know that 21/82 works as I'm running that combo in one of my twin hammers.

[Bjorn]

Right on, any suggestions on pins to use in the cv shafts? I've been making my own with Allan keys, I figured tool steel would be a bit tougher, but the torque is snapping them too. I've broken at least one a day as I run the piss out of my rig on a daily basis.

[Bjorn]

I cut a pin from a 1/16 drill bit, seems to be the ticket so far. First run I've had with the new motor/esc without snapping the c/v, going to change them all, probably will break something else now!

[meatmonkey]

Most drill bits make good drive pins for RC cars. In my experience the best way to prevent broken cvd's is to NOT run the front diff locked. I have one twin that is locked and it will occasionally snap cvd pins when landing large jumps at awkward angles, but it is setup for mostly crawling. I have another with 1 million weight oil in the front diff and have yet to break a pin despite more power and more abuse. The pins do wear though, so replacing them when the joints get sloppy is good preventative maintenance. You do give up crawlability with the front diff, but it sounds like your using yours as a general basher?