Granite Granite 3s bent motor mount, front motor bearing destroyed

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Arrma RC's
  1. Granite
Granite locked up on me today and when I got home and started narrowing things down, I noticed that it's the motor that's locked up solid and motor mount is bent crooked. Pulled the motor apart and the front bearing where the shaft comes out falls to pieces. Do you guys think the bent mount caused that bearing to fail? Has anyone gotten Arrma to replace their motor mount and do you thinky they should/would replace my motor? I got the truck in June for fathers day, so it's only a few months old. Is there a brace or mod that can be done to prevent the mount from bending?
 

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Only you know how it's been driven and I feel you should have some sort of feeling if you should pay for a new one or not. Yeah? ;)
 
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Sheesh... I would say you're up sh*t creek with Horizon/Arrma on replacements for the motor mount. Could try with the motor.
 
The front bearings in these motors are known for going bad really fast.

It is highly unlikely that the mount bent then caused the bearing to explode.

Most likely what happened is the bearing locked up and the force from the motor locking up caused the mount to bent, if that is the least of the damage then I say you came out good. When the motor locked up mid backflip on my Outcast it took out both front and rear diffs, the crown and pinion gears were toast, the internal gears in the front were toast and I broke a pin in the rear.
 
I would guess that yes, the bent motor mount caused the pinion to sit at a weird angle to the spur and put a lot of side forces on the bearing which caused it to blow up.

I would also guess that you ran into a tree/curb/car/whatever and bent that motor plate due to bad driving and I don't see why you would think Arrma should warranty a part due to bad driving.
 
I would guess that yes, the bent motor mount caused the pinion to sit at a weird angle to the spur and put a lot of side forces on the bearing which caused it to blow up.

I would also guess that you ran into a tree/curb/car/whatever and bent that motor plate due to bad driving and I don't see why you would think Arrma should warranty a part due to bad driving.
As @slick2500 wrote it's the other way around. The motor bearing exploded causing the trouble.
For what i have seen it's due to the tight gear mesh.
Get some good bearings (ceramic sealed ones are the best for motors from my experience) and an adjustable motor mount from Armma or HotRacing.
Set the gear mesh properly and have fun!
 
Is there a brace or mod that can be done to prevent the mount from bending

Hi Jake,
I did a patented brace. Without them, my son 3s Typhon (and the old Mega) power module will be destroyed. Even if we run on carpet at the track.
https://www.arrmaforum.com/threads/new-typhon-3s-coming-in-old-mega-on-brushless-conversion.11725/

Yes, we will have bented 4x2 screw after a session, but I can live with it.

Slick has a point about the so-so bearing motor quality. I add a very little drop of lube after each w.-e. session. So, I don't open motor until november.
 

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Mhm this happened only to my motor mount. I was going 40kmh and hit a rock that i never saw and the otehr time a drain curb and my gear mesh became tight i just hammer it back streight but i was dumb and use a steel hammer instead of a rubber one. So i ended up completly ruining it the second time. Moral of this is try to avoid hard nose landings and hiting a tree or a rock at high speed
And whats the bearing size of the 4s motor? I never menaged to find the size
 
Mhm this happened only to my motor mount. I was going 40kmh and hit a rock that i never saw and the otehr time a drain curb and my gear mesh became tight i just hammer it back streight but i was dumb and use a steel hammer instead of a rubber one. So i ended up completly ruining it the second time. Moral of this is try to avoid hard nose landings and hiting a tree or a rock at high speed
And whats the bearing size of the 4s motor? I never menaged to find the size
I would like to assume that they would be the same size as the BLX100 and that is 5x13x4, this is also the size of the front bearing in the blx185.
I would guess that yes, the bent motor mount caused the pinion to sit at a weird angle to the spur and put a lot of side forces on the bearing which caused it to blow up.

I would also guess that you ran into a tree/curb/car/whatever and bent that motor plate due to bad driving and I don't see why you would think Arrma should warranty a part due to bad driving.


As @slick2500 wrote it's the other way around. The motor bearing exploded causing the trouble.
For what i have seen it's due to the tight gear mesh.
Get some good bearings (ceramic sealed ones are the best for motors from my experience) and an adjustable motor mount from Armma or HotRacing.
Set the gear mesh properly and have fun!

It very well could have been a combination of both, but I have seen more posts of people blowing out that front bearing than I have seen bent motor plates. Heck I've seen quite a few people who are on their second or third motor.
 
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Ugh, I just opened up my Kraton 4S and the motor plate is bent too. Who makes a billet version? This 6mm cast piece is not impressing me if it can bend without breaking the chassis.
 
Ugh, I just opened up my Kraton 4S and the motor plate is bent too. Who makes a billet version? This 6mm cast piece is not impressing me if it can bend without breaking the chassis.
Told you
We need a fromt bumper
Might be one of my upgrades but i hate the look of the t bone bumper made for the kraton 4s i wanted something like what the typhon 3s version has
 
Told you
We need a fromt bumper
Might be one of my upgrades but i hate the look of the t bone bumper made for the kraton 4s i wanted something like what the typhon 3s version has

You're right, I was wrong. Not sure when it got bent, last time out I let my buddy bash/crash it and he was doing some cringe-worthy things with it.

Personally I think the motor is probably too heavy for the motor plate. It's the same design as the 3S which has a much lighter/shorter motor and doesn't put as much leverage on it.
 
You're right, I was wrong. Not sure when it got bent, last time out I let my buddy bash/crash it and he was doing some cringe-worthy things with it.

Personally I think the motor is probably too heavy for the motor plate. It's the same design as the 3S which has a much lighter/shorter motor and doesn't put as much leverage on it.
The only thing i don't like about the 4s kraton is the dam buggy bumper it has
 
Ugh, I just opened up my Kraton 4S and the motor plate is bent too. Who makes a billet version? This 6mm cast piece is not impressing me if it can bend without breaking the chassis.
I wonder if the Hot Racing mount would be better than the stock one :unsure:
 
I ordered an Arrma adjustable one. The HR one looks like it has cooling channels in it, which I really don't need and probably weakens it a little bit. Hopefully the Arrma version is billet.

Looking back now I remember my truck started making some weird noises while running and my buddy kept driving it and I was like "hold on! it's making some weird noises". I couldn't find anything wrong with it, so we kept running it. I'll check/change the motor bearings when I change the motor plate.
 
I ordered an Arrma adjustable one. The HR one looks like it has cooling channels in it, which I really don't need and probably weakens it a little bit. Hopefully the Arrma version is billet.

Looking back now I remember my truck started making some weird noises while running and my buddy kept driving it and I was like "hold on! it's making some weird noises". I couldn't find anything wrong with it, so we kept running it. I'll check/change the motor bearings when I change the motor plate.
Did your check if there is any wear on the pinion and spur?
I will receive my ceramic motor bearing tomorrow and put it in the front of the motor
 
Did your check if there is any wear on the pinion and spur?
I will receive my ceramic motor bearing tomorrow and put it in the front of the motor

There's a bit of wear on the pinion, but I'm just going to run it for now.
 
I’ve owned both the Arrma and HR adjustable mounts and bent them both. I think my rear motor support idea is the best way to keep the motor in place. That plastic power module only has so much room, so you can’t use a thicker plate.
 
Hey i just siwtched my front bearing from my motor with an acer racing ceramic nitrite bearing and now i don't have tight spots in my spur! So now it should stop wearing down my pinion hopefully!
 
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