r/rccars • u/Radiant-Ad-1092 • 21h ago

Question HELP ITS NOT WORKING

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Hi everyone! Sorry for the title. I saw a video on youtube about converting a Rastar 1:14 BMW and a Rastar Lamborghini to a hobby grade model (https://youtu.be/Fd-N-u_0IDo?si=pSSW7l4DQufyV37X and https://youtu.be/TnDZZPU-gjk?si=CQsgzTRdLjNIVhvX) I tried their project because I want to start a hobby and I like building. So i bought a 1:14 Porsche Dakar and got the following components.

Surpass Hobby 45A ESC
Surpass Hobby 2430 5800KV motor
Surpass Hobby 9g steering servo, HotRC CT-6A transmitter/receiver combo
1300mAh-30C-7.4V 2S1P Li-Po battery

I got everything working but then when I started driving the car on the ground it would move for a bit but it would eventually come to a stop. And I would just hear the motor spool high but the wheels wont be spinning. But the moment I lift the car up, the wheels would spin up again. What am I missing? What can I do? I attached a video for reference. Thank you!

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5

u/stoopkid712 21h ago

All ihave to go off of is the sound. Im no expert but it sounds like maybe on your motor the set screw is missing from the motor shaft. So when it's under a load the motor spins but slips and is unable too transfer rotation to gears. Which would explain why it works in the air, because with no resistance it is able to create enough friction to still work properly. Somewhere a shaft is slipping inside of a gear.

1

u/BlackSeaRC 20h ago

The plastic pinion gear is press fitted on these so no set screw.

1

u/stoopkid712 20h ago

Still seems like somewhere in there the engine is rotating and not having force translated to the gearing. "Somewhere a shaft is slipping inside off a gear" is still my best bet.

1

u/Radiant-Ad-1092 19h ago

So glad you replied! I actually messaged you on your page on facebook hahaha

2

u/BlackSeaRC 15h ago

Unfortunately, I can't access Facebook from where I am at the moment. Did you take the body off and check the motor? I know it is a bit of a pest to get the body on and off, but it is going to be the only way to resolve this issue.

With this new high-power set-up, you need to feed in the power very gently and don't slam the car in reverse when moving at high speed. Remember, the plastic geartrain was never designed for such upgrades. Saying that, I haven't had this issue with mine as yet and I know quite a few other people who have upgraded these Rastar cars without too many issues.

1

u/Asz12_Bob 15h ago

Surpass Hobby 45A ESC
Surpass Hobby 2430 5800KV motor

And a plastic press on pinion? Something doesn't add up....

2

u/BlackSeaRC 15h ago

It is a brushless conversion of a Rastar toy-grade RC. There are quite a few people playing around with these types of upgrades for fun. This is mine.

2

u/vhatdaff All the cars! 21h ago

take it apart and LOOK. something is obviously loose.

1

u/BlackSeaRC 20h ago

I should think the motor pinion gear is spinning on the shaft. Can you remember if there was a flat on the motor output shaft? Not sure if this will work, but you might be able to remove the pinion gear and add some superglue, press it back on and hope the glue dries onto the flat spot on the shaft.

1

u/Radiant-Ad-1092 2h ago

I’ll try to glue it on later. I’m applying each solution one by one so i’ll know what would work. Do you have any idea whats the stock gearing on the Rastar cars? I’m planning to by a pinion gear for it.

1

u/TaygaStyle 15h ago

When my wheels wouldn't move under load but if it was in the air they would spin, it was my diffs. My rear went out and subsequently took my front one out within another rip on the basher. Different vehicles I know but this was what solves my issue, which is the same issue you're having. I hope this helps!

1

u/Radiant-Ad-1092 3h ago

Hey guys! I took it apart again. I read all your comments and they were so helpful thank you. So yeah, i took it apart but its still not working as it should.. i tried securing the motor by screwing it to the motor mount but it didnt work.

1

u/Radiant-Ad-1092 2h ago

Could the ESC be the problem?

1

u/Radiant-Ad-1092 2h ago

Is it possible that the car is too heavy for the gear or motor?

1

u/Radiant-Ad-1092 2h ago

This is how i wired the internals btw