Granite Arrma Granite slowing down

[RhinoKeegan]

Hey all,

I bought 2 brushed Arrma Granite 4X4 trucks a couple weeks ago for my boys. Both trucks are running the stock NiMH batteries.

Both were equally fast but now one of them is noticeably slower. Like the motor isn't getting full voltage. Slower in forward and reverse. It's not the batteries (we swapped mid-run and no change), and I've made sure the throttle trim isn't the issue. Could the motor be damaged? I have noticed that it gets quite hot and there was a distinct "hot electonics" smell after a recent run.

If it's the motor, will Arrma replace under warranty? Again, only a couple weeks old. I really don't want to spend the money to go brushless right now as I just dropped almost $500 on two trucks.

Thanks in advance for any help.

 

[Mongoose]

It is definitely possible that it’s the motor I know they can get piping hot. Arrma should warranty the motor if you contact them.

Another thing to look at is any binding in the drivetrain. Even the slightest resistance will cause it to run slower and get hot quicker. What you would think isn’t a big deal by moving with your hand can be actually be a lot when it comes to the motor.

Usually the way I kinda “feel” it is by rolling it across the floor. Set the two side by side and push each truck with the same force and see if the truck in question stops short of the other. Roll it back and forth and compare the two.

This is a pretty archaic way of troubleshooting but it’s quick and easy and doesn’t involve taking it apart and getting real involved with it. It’s nice to have the two trucks to compare.

 

[arrmadillo]

If the motor is getting real hot and smells burned up, it could very well be bad. Did you take temps and compare the two.If you just bought them and motor is bad, I see no reason why it can't be warranted.

 

[RhinoKeegan]

Both good suggestions! Thanks! I was thinking of swapping motors between the trucks to see if I could identify the problem. I'll be calling Arrma support for sure if the motor is the culprit. I've read quite a few posts about the stock motors not lasting that long. If they prove to be a weak point, are there better brushed motors to swap for? We don't race and don't need the speed of a brushless truck.

 

[arrmadillo]

Both good suggestions! Thanks! I was thinking of swapping motors between the trucks to see if I could identify the problem. I'll be calling Arrma support for sure if the motor is the culprit. I've read quite a few posts about the stock motors not lasting that long. If they prove to be a weak point, are there better brushed motors to swap for? We don't race and don't need the speed of a brushless truck.

Can't suggest any brushed motors, haven't had a brushed motor in 15 years. Lol

 

[Mongoose]

Read through this thread, Peeenut suggests a Holmes Hobbies motor because of this issue. Brushed motors are cheap.

https://www.arrmaforum.com/threads/granite-4x4-motor-heat.12882/#post-154184

 

[scv484]

Mine lasted like 8 months. I actually didn't realize it was getting slower, until HH warrantied it and I put the new one in. LOL. Also, I lost reverse as well in stages.

 

[sadlerbw]

I think my stock brushed motor lasted about 4-5 months of regular use. Then, one of the armatures holding one of the brushes failed and off to brushless I went. ARRMA may give you a free replacement under warranty, but even if they don't there are 12T, 550-size Traxxas and ARRMA motors all over Ebay for $20-$30. You can just drop another one in and keep going for a few more months. Sure, that would add up over time if you had to do it repeatedly, but after six or eight months your boys will likely want to move on to something more powerful anyway so it really isn't that bad of an option.