I have a ROC412 1800KV and an RX8 gen1 ESC. At low throttle it is really smooth. At about 20% throttle I start to get intermittent ratcheting. It will rev up to full speed but you can still hear the ratcheting a little. It is the same with the sensor wire plugged in or unplugged. I'm running it on 4S and the timing on the ESC is set to #1. I just pulled the ESC out of my Tekno to put in another car. The ESC was working great in the Tekno so I'm 90% sure the problem I'm having is with the ROC. The ROC motor is out of an old SCX10 and was working good when I last used it but the rig has been sitting for the last 3 years.
I looked at the lights on the ESC for the sensor checker. They are really hard to see but I think only two are lighting up. I was going to order a new PCB from Tower but they don't carry the TT2613. They only have the TT2513 for the Pro4 motors. Will that work?

Tekins are touchy. Anytime you change motors You must Calibrate the ESC. If it doesn't remedy it, try your gear ratio, to a smaller pinion. What is size of pinion and spur? if 3 led of sensor don't change states, sensor board or cable defective.

Gearing right now is 86/17 and the motor acts the same when the sensor wire is unplugged.

Series ROC motors are rated for Rock Crawlers. If using a Hotwire turn on sensor. if not set sensorless. using hotwire will open that function. LED's 5,6 & 7 should flash by turning the pinion by hand slowly. Hotwire does open other files than the blinky mode. Hotwire Shows Sensor or sensorless, motor timing and boost.

Not into rock Crawlers, would think smaller pinion would work, Try larger pinion. see if it improves.

After I got the truck together it seems to work well enough. It's in a Proline Pro-MT. I tried it with a 17T pinion first. It wasn't quite fast enough. Motor was barely warm too. So I threw a 21T in it. Much better speed. You don't notice any cogging in the car while driving it. You only notice it when you pick up the rear end and run it. I've decided not to mess with it. I do think I'm going to get a 23T pinion for it though.

I stated ROC Series motors rated at crawler rc's. Maybe the wrong motor for the MT. may cuz it slow. Crawlers are slow moving.

Did You calibrate the ESC? Follow manual to calibrate, make sure the motor chimes, insure that its calibrated.

Yea, I've run the latest update available for the Gen 1 RX8 and set all the parameters with the Hotwire. Calibrated the ESC to the TX as well.

One things for sure, it has plenty of power. With 1800KV on 4S I can wheelie at any time.

Calbrating esc to TX!! Actually Calibrating esc to motor not TX. Brushless motor needs to find home for it. The only thing left to ask you timing and and motor setup to see where you're at. Motor at Bl/ FWD and Br, or BL/Rev?

When you updated Software did you recalibrate it?

I'm just shot gunning at this time! cuz out of ideas.

The TX is calibrated to the ESC. Have the timing a 1 right now. I might go up to 5 to see what it does but I want to put the 23T pinion on it first.

I just want to say that at this point I'm very happy with how everything is working. I can't explain the weird cogging at no load but it doesn't do it under load when driving it so it's all good.

With a 2 pole motor you drop teeth on pinion, with 4 pole motor like the ROC you can drop from 17t pinion(15t-14t) is my guess.

Good luck!! Getting it to run with no glitches with or without load your goal. Remedies problem in long run.