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M.L. Toys
KidsWheels
Gruber
HobbyMasters
M.L. Toys
KidsWheels
HobbyMasters M.L. Toys
Gruber
KidsWheels
Anything that doesn't fit somewhere else & general forum updates
User avatar
By PW_Newbie
#146985
Hello all! It all started when my girls escalade PW battery needed replaced. So long story short i ordered 3 6V batteries to upgrade. I plan to use them in series, and use a 4p2t switch to put back in parralel for charging. So i spent hours on this forumn researching. I want to keep her car reliable, so im swapping her brake resister with a .47 to help gear wear, and putting fanless heat sinks on motors. Many people say to switch to the 775 motors if you up voltage because they hold up better. They also say 775 increases torque, but not really speed. Wouldnt an increase in torque be harder on the gearbox??? So i guess my question is this, with 18 volts would 550 with heat sink last longer than the gearbox a 775 is running at 18 volts? My girl rides on flat ground, mostly grass but also some gravel driveway time. Seems gearboxes are more expensive than motors. If my motors burn out i plan to put cold air intake with fans to cool replacement motors. Please correct me if my way of thinking is flawed. Thanks for all the great material on this site by the way.
User avatar
By Hammer-fm
#146998
Several things will kill gearboxes. One problem I had was that that heat from the 550 motor at 18V+ would end up transferring into the 1st gear and gearbox, soften the plastic, and allow the pinion shaft to spin or strip teeth off the edge.

Running a 775-motor keeps the temperatures down. But you're right, it's going to push more torque. Even if you get a relatively tame 775 motor (such as the Nichibo 775-7013F), it's still 33% more torque. Most people run 'hotter' 775 motors; if you get something like the Banebots motor and you're running w/o an ESC or other current limiter, it'll be 2.5x the stock torque and will break things for sure. An ESC or other current limiter will help reduce strain on the gearbox by limiting the peak current (which in turn limits the peak torque), and should be considered a hard requirement if you're going to put in a motor like that.

You can reduce the overall torque applied to the gearbox by getting a gearbox (and pinion gear) with a higher tooth count, eg. go from a 17T (I think the Escalade stock) to a 22T. The higher tooth count means less force at the interface between the two gears. But you have to buy a new gearbox case (can be empty -- the gears just swap over) for that.

For instance, iIf you go with the 'more-like-stock 775-7013F motor, with a 22T gearbox & gear, that setup would help get rid of some of the heat and you'd get a 30% speed boost (vs. 17T stock) and the same torque as the stock motor -- if running at 12V. When you push it to 18V it's obviously going to be 50% more of both (torque & speed) again. Total cost is going to be $20-25 (two empty gearboxes), $16 (4 motors), $16 (two pinions), and some effort -- so $60-70 for that changeover.

Is it going to be reliable? At 12V, everything would probably last a very long time. At 18V, the motor will probably run forever. I'm not as certain on the gearbox at that voltage, as I've broken a few various gears even with fairly 'wimpy' current limiting -- when you're running 8-9mph and the kids are spinning the wheels on uneven surfaces, things sometimes break.

BTW, kudos on the doing the brake mod -- that's a huge help on reliability.
User avatar
By PW_Newbie
#147004
Great information! Especially that a hot 550 motor is actually hard on the gears. Never thought of that. I got thermal paste and a heat sink that i will put on, so hopefully it helps a little. I already ordered my parts so im gonna go ahead with stock 550, heat sink, 18 volts, and .47 brake resister. If/when something breaks the configuration you posted is what i will switch to. Thank you for your answer, its just what i needed to know.
User avatar
By lexx0116
#147260
So I am at the point right now to consider my next option. Like Hammer stated above, I have dune racer with stock gears and motor. Things i have done so far are:

1. Soft start system by CJB (Turbo Timer 4 board)
2. Break reducer by MLToys
3. Fanless heatsink to the 550 stock motors
4. 18v battery setup (12v + 6v in series)
5. Bike tire mod for wheel for grass terrain

When running at 18v, the soft start worked great when started out at slow speed for 2 sec then speed up to full 18v speed. Break reducer works great also. However, I noticed the stock motor gets hot faster than 12v (i think this is a given since we increase the voltage by 50%). When going up the grassy hill, the fuse broke a couple times. I touched the wire (warmer than 12v), the motor is hotter than 12v even with heat sink. I saw a video from Glorrydays here for his dune racer mod from 12v to 24v with fans support so that what I will try next by adding heat sink with fan and a couple of fans to help out with the cooling but that means I have to add in another 6v for the fans power source. I also ordered the motor suggested by Hammer and will try that out too if my plan B fails. I think my problem right now is the grass terrain and hills. I need more torque for these. Lucky I have spare dune racer to work on this so my kids can still enjoy their ride at 12v stock setup. If ESC is easier to install and less expensive, I would have try it too :)

@skinbin, yes of course.

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