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strange sound when coasting to a stop

strange sound when coasting to a stop

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Old 05-07-2019, 08:40 PM
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Default strange sound when coasting to a stop

I'm new @ rc cars. I started a couple of months ago with a Legend and been running on carpet ovals. My 2nd car got a new Reedy 17.5T and a Blackbox ESC. They came as a pair and have worked ok from day one. The only thing is the car makes a funny/loud sound the last couple of feet when coasting to a stop. It sounds like ratcheting. Everyone gets a good laugh the first few times they hear it. Not a soul at the two places I run have a clue what it comes from. All the experts who've looked at the car check the gear mesh. The 48P OEM set passed muster from 3 or 4 different experts. I've now got a 64P set installed that is quieter than the 48P was, but didn't affect the strange sound at all.

I've reset the ESC mode. Or more exactly I've "restored default' (the 6th MODE setting).

I've tried two different sensor wires from the Reedy motor to the Reedy Esc. Same sound happens.

I can adjust the TX's throttle and brake amounts and the car responds correctly. BTW, the car doesn't slow to a stop any faster or slower when the sound kicks in. The sound does taper off as the car comes to a stop.

Anybody experienced this and know the fix?????
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Old 05-07-2019, 08:53 PM
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Don't worry about it. That's just the brake. Sometimes they get noisy at low speeds.
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Old 05-08-2019, 05:26 AM
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Any chance you might have dropped a small metal object into the motor or is the can fully sealed?
I would consider pulling the rotor out and inspecting for any loose screws or washers that may have inadvertently got sucked up into the motor through the cooling vent holes.
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Old 05-08-2019, 10:54 AM
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Originally Posted by frewster View Post
Don't worry about it. That's just the brake. Sometimes they get noisy at low speeds.

A number of experienced racers thought that too, but the car is obviously coasting to a stop while making the noise.

I'm not on the brakes (or throttle) at all when it's coasting.
The ESC and TX has been calibrated by a number of different drivers who're Reedy fans.
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Old 05-08-2019, 11:11 AM
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Any chance the motor got any moisture in it? If so, then I wonder if the bearings in the motor might need to be replaced if any rust has formed and/or caused any of the bearings to go out of round/seize causing a screeching sound.Could be any bearing in the car for that matter.
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Old 05-08-2019, 11:26 AM
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Do you have drag brake turned on?
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Old 05-08-2019, 12:39 PM
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Originally Posted by billdelong View Post
Any chance the motor got any moisture in it? If so, then I wonder if the bearings in the motor might need to be replaced if any rust has formed and/or caused any of the bearings to go out of round/seize causing a screeching sound.Could be any bearing in the car for that matter.
The motor and ESC are brand new. Only seen dry carpet.

I've got some BOCA bearings coming. Will find out in a couple of days. There is no indication from the rears that those are anything but free.
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Old 05-08-2019, 12:44 PM
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Originally Posted by frewster View Post
Do you have drag brake turned on?
According to the instruction sheet, the ESC comes with 0% drag brake.
The ESC is one of those "beepers" so it isn't easy to tell what the settings are, and harder to set them. A couple of Reedy 'experts' have restored the settings and calibrated the sucker. It's supposedly got NO drag brake and no optional settings. Just forward and brake from the throttle.
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Old 05-31-2019, 11:37 AM
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OP is this the sound your talking about? I believe itís just the sound of the motor at low speed. This is a REEDY 13.5 S+PLUS with a REEDY 510R.

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Old 05-31-2019, 12:01 PM
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Originally Posted by Krogers View Post
I've reset the ESC mode. Or more exactly I've "restored default' (the 6th MODE setting).
6th Mode is Not default......
If you confirm that is in in fact in Mode 6, the sound you are hearing IS the drag brake and the resistance it is inducing in the gear.
6th mode has 25% drag brake

Try setting to MODE 1 instead.
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Old 06-02-2019, 09:21 AM
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Originally Posted by NoEffects6 View Post
OP is this the sound your talking about? I believe itís just the sound of the motor at low speed. This is a REEDY 13.5 S+PLUS with a REEDY 510R.

https://youtu.be/Oq9Z26oUKx8
I am running a 17.5 turn Hobbywing Bandit Gen1 in my Tamiya TB-03.
At ​low rpm, car sounds like a shaken bag of screws nuts and other metal stuff, just like yours. At higher speeds: silence.
I think this ist related to the high torque character of these Motors.

Regards,
Michael
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Old 06-02-2019, 07:33 PM
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Weird things happen when the rotating magenetic field is less than synchronized to the rotor. On a stepper it kind of sounds like whales talking. Do you have a frequency setting for the brake or PWM?
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Old 06-11-2019, 10:26 AM
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Does the car make the noise if you roll it by hand? My new 13.5 Splus motor does the same thing. It is due to the motors magnetic "indents" if you turn the motor by hand you can feel the motor "slip" from one spot to another. So at low speeds that motion is transferred to the drivetrain and any slop in the drivetrain will kinda slap back and forth. Hence why it only happens under no load from brake or accelerating. or even light load during slow starts or stops.
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