Big Rock 20T Pinion Bashing Issues

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Mirovingian

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Location
Dubai, United Arab Emirates
Arrma RC's
  1. BigRock 4x4
Hey there peoples,

I've had the Arrma 20T pinion fitted to my Big Rock a couple of days ago, and noticed that it overheats half way through the battery pack on light bashing. My backyard is not even big enough for the thing to stretch out its legs out anyways, but I'd like to have an all purpose setup so I can run it on my front street for speed runs when I feel like it.

I do have the Arrma motor fan installed too, but my punch level is on 5.

The car runs again as soon as I turn the power off and on. Not sure if that's just tricking the ESC into working again or what exactly, or if it's even recommended to do that.

Any tips on how to handle this issue and have a permanent all around 20T setup?

Thanks in advance all.
 
20t will over heat when bashing no way around it. Get an adjustable motor mount and an 18t. Best for both speed and bashing
Thanks man.

I do have the adjustable HR motor mount on the side, but it's not as beginner friendly to use as the stock motor mount so I haven't used it.

Any links or posts on how to use it with the 18T pinion correctly in terms of meshing...etc.?

Thanks in advance.
 
What you’re experiencing could be thermal, or it could be premature LVC due to the amp loads you’re trying to pull thru a BLX100 ESC. I had these issues when trying to use too large of tires on 20T or above. You can run up to a 18T with large tires as long as you have the motor fan. You will have cogging in the low end tho. If you want to avoid heat and cogging, 15T is the limit on larger diameter tires.
 
What you’re experiencing could be thermal, or it could be premature LVC due to the amp loads you’re trying to pull thru a BLX100 ESC. I had these issues when trying to use too large of tires on 20T or above. You can run up to a 18T with large tires as long as you have the motor fan. You will have cogging in the low end tho. If you want to avoid heat and cogging, 15T is the limit on larger diameter tires.
Thanks for the insight man.

I'm running 2.8" trenchers, which I assume are the closest thing to stock diameter wise at least. Here's a pic.

20200329_235808.jpg


I did face the cut off on 15T when running the 3.8" though, battery would cut out at 35%. Here's a pic of that one too. There's a bit of rubbing against the chassis on full turns, but otherwise a lot more fun to bash and jump with.

20200327_010342.jpg


Too bad the early cut off sets in, or the HR extenders do not hold on tightly enough, loosening throughout the run.

I'll research about the adjustable mount for now.

??
 
20t is going to cause heat. I tried it and went back to an 18t. Gear mesh isn't that hard to figure out. Don't let that intimidate you. I usually start with the two gears meshed tightly. I then back off a little and rock the two gears back and forth. I like to have a little lash between the two. You you can tell if it's too much by looking at the gear teeth and seeing that only the tips are contacting each other. You will also notice that there is a lot of movement between the gear before they touch. That's too much lash or too loose. It will be too tight if you can't rock the gears at all without them both moving. You will also see the teeth fit together like pieces in a pie. That's too tight. A lot of it is just feel, but it's something you should learn how to do. Give it a shot and post a video so we can help ???
 
20t is going to cause heat. I tried it and went back to an 18t. Gear mesh isn't that hard to figure out. Don't let that intimidate you. I usually start with the two gears meshed tightly. I then back off a little and rock the two gears back and forth. I like to have a little lash between the two. You you can tell if it's too much by looking at the gear teeth and seeing that only the tips are contacting each other. You will also notice that there is a lot of movement between the gear before they touch. That's too much lash or too loose. It will be too tight if you can't rock the gears at all without them both moving. You will also see the teeth fit together like pieces in a pie. That's too tight. A lot of it is just feel, but it's something you should learn how to do. Give it a shot and post a video so we can help ???
Well if it ain't Mr. Wham-Bam-Bickety-Bam. Enjoyin those YT vids you put up.

You spared me a ton of video sifting with this post of yours. Got every angle covered. Thank you bud'.

That dog 18 by the way? JK man ?
Time to make that Big Rock squeal, and that warranty come to think of it.?
 
Thanks for the insight man.

I'm running 2.8" trenchers, which I assume are the closest thing to stock diameter wise at least. Here's a pic.

View attachment 72634

I did face the cut off on 15T when running the 3.8" though, battery would cut out at 35%. Here's a pic of that one too. There's a bit of rubbing against the chassis on full turns, but otherwise a lot more fun to bash and jump with.

View attachment 72636

Too bad the early cut off sets in, or the HR extenders do not hold on tightly enough, loosening throughout the run.

I'll research about the adjustable mount for now.

??
If those Trenchers are Belted, just know the added weight will have a similar effect as 3.8” tires. They will drop your voltage and add heat as well. If they are standard Trenchers, then you can treat them pretty much as stock Ragnarocks as far as heat and gearing.
 
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