Newbie gearing help

[mjz1981]

I'm a newbie who recently bought a used XXXT MF1. I went and practiced for the first time with it on the track last night, and I struggled with the gearing and slipper. For a 27t stock motor, whats a safe number to use to get me around the track. I had the purple[help, if you know where the color chart is] spur gear on...which doesn't help because I can't find the color guide, unless there was a number on the gear and i couldnt read it.

I know I still need to change the gearing to fit the track, but i only ask because my first pack(i used a 23 tooth), the motor got too hot, then later on, i wound up burning up the old stock motor i was using (25),, but that was because the pinion gear loosened up and it hung itself on the side of the spur gear, and the motor couldn't turn...not sure how that happened...i guess the pinion screw got loose.

Also, whats a quick check for setting the slipper clutch. I had too much wheel spin off the line, so I should "loosen" the slipper. Am I right?

[SteveK]

I don't know any numbers for the gears or ratios (Depends on the track, and I don't know the internal ratio of the XXX-T), but if your motor is too hot to touch after a run, you're overgeared. It's also a waste if the truck doesn't real full speed anywhere on the track.

For the slipper clutch, generally you want it to slip for about 1-2 feet. With the battery fully charged, just do some hard starts in a few areas of the track and loosen or tighten the clutch until it feels right. If you get too much wheelspin, loosen the clutch, but don't go too loose or you'll generate a lot of heat and risk melting the spur gear.

If something happens that makes the truck run or sound funny, like the pinnion slipping off and jamming against the spur, then stop the truck immediately and check it out. It could save your motor.

[highroller]

First try to find the spur gear size, number is usually molded somewhere on it color is not always the number or size. Exact gearing will also depend on which stock motor you are using along with the track layout, conditions and vehicles tire and transmission ratio. High rpm motors would need to be geared lower (pinion with less teeth) like the Monster Stock2, GM3 while motors with lower rpm ranges would be gear higher (higher tooth number) motors like the P2K2, MVP or Orion/Peak.
Ask some of the local racers who are using similar items as you (vehicle and motor) what spur and pinion they are using to be safe start one or two teeth lower, practice then add one tooth until you achieve the right combination of lower lap times while motor temperature stays in a good temperature range some may feel extremely hot but also look at condition of brush and comm if those show no wear or discoloration gearing is right in the ball park. As you make changes look at how vehicle is accelerating, how it gets up to speed, also notice whether it continues to maintain that speed throughout the timed race distance or tends to slow (it should never slow if using 3000 or higher capacity batteries if gearing is correct) mid way through the race and battery still has plenty of voltage left, after inspecting brush and comm it looks worn or discolored then gearing is too high. With 2400 or lower capacity they should run pretty strong right near then end to about the 4.30 to 4.45 min mark of a 5min heat. On extremely hot days it may be benefical (allow motor to run stronger) by gearing down one tooth to allow motor to run cooler.

[mjz1981]

Thanks..Matt