Tuesday, September 15, 2020

RC Car Fun!

 Sorry, no videos, although I did dig out the GoPro mount for the little red RC truck.

We had so much fun blasting around the front yard, that after TLG went home with his Daddy, I dug up the other set of wheels and tires I bought last year, along with my aviation snips to modify the body a bit.

Why modify the body? Well the new tires are a bit bigger than what came on it:



I had already changed the pinion gear on the motor so that the overall gearing would be the same. With the small wheels and smaller pinion gear, it had a lower top speed, but got there right now! The larger wheels give me back the top speed I lost, and the acceleration is way more than "adequate". The larger tires also make it easier to go over things, like the wacky curbs we have here.

I snipped out the body trying to follow existing body lines, and after a few minutes I had this:


I put a flap-wheel in my Dremel and smoothed out all the rough edges. This plastic leaves SHARP edges when you trim it. They can slice you open. It hurts, and you get blood all over your model car. DAMHIK....

And I swapped out the hard plastic steering wheel on the transmitter with a nice, soft, foam unit. Cost about $6, and makes the car much more fun to drive.

So how did it work? Better than I expected. By putting these tires on I now have enough additional ground clearance that I can charge the curb at full-power, get launched about 3' into the air, and carry it out about 12' before it comes back to earth. Couldn't do anything like that before! And as long as you back off the throttle as soon as you get airborne, you won't break any driveline parts when you smack back down.

I tried running it before I swapped the tires, and I wasn't happy with it. I was using a cheap 2S LiPo rated at 4000mAh with a "20C" discharge rate, and it just felt really sluggish. It accelerated to top-speed almost instantly, but with the little tires it just didn't go very fast. Now with the larger tires, the gearing is back in the correct range for this motor and speed control package, and it really honks. I also decided to try one of the 2S 5300mAh/75C batteries I have for my little Vintage Trans Am car. These are far better batteries, and the little Senton is a road rocket now. I'll try it again with the new wheels and the cheap LiPo to see if it's as sluggish as it was with the smaller tires on it. I wouldn't expect there to be that much difference between the two batteries, but it's possible.


  1. You're having way more fun than I am. Whose fault is that, I wonder..? Hmmm. :)

    1. And for "Snow Days", Kyosho makes one of these:

  2. Envy your skills to do that sort of thing. My latest accomplishment is driving a long enough screw to find real wood for my flag mount.

    1. Just swappin' parts, WSF, not terribly hard to do.

  3. Question is, what are you doing to the geometry, and unsprung weight adding that much stress on the suspension components?

    1. These parts cam from a slightly different Arrma model. The "Granite" is a twin of theis "Senton", but with a Monster Truck type body instead of the longer wheelbase "Short Course Truck" that this one is.

      The only "downside" to this swap is that if you don't change the pinion to correct the gearing for the taller tires, the truck won't accelerate very hard, and the motor will be undergeared.

      The suspension and other parts are so overdesigned that it doesn't matter otherwise.


Keep it civil, please....