SCX24 Issue. Need Help

[BirdRacer99]

I have an SCX24 C10. The other day it started driving really slow even with a fully charged LiPo. Holding the truck up the wheels are spinning slowly (even slower in reverse), but when i put the truck down it goes even slower (low torque).

All of my other vehicles are 1/8 or 1/10 scale bashers, so i don't have any experience with these micro crawlers. I took apart some things to try and diagnose the issue. The pinon and spur gear seem to turn pretty fast, but the rods coming out of the center diff are turning much slower. One other thing is when i turn off the drag brag it seems to run even slower.

Does this sound like a motor issue, center diff issue, something else?



extra info:
- I burned out the stock esc/rx combo (reversed polarity when soldering battery adapter ) and am using an hpi esc and a spektrum dsmr rx.
- I am using an off-brand 550 mAh 80C 2s LiPo

esc specs:
Forward Continuous / Burst Current: 40A / 180A
Reverse Continuous / Burst Current: 20A / 90A
Motor Limit: 2S LiPo or 6 cell NiMH: 540 or 550-size motor great than or equal to 12 turn, RPM over 30,000 at 7.2v
Motor Limit: 3S LiPo or 9 cell NiMH: 540 or 550-size motor great than or equal to 18 turn, RPM over 20,000 at 7.2v

 

[JatoTheRipper]

Welcome to the site!

It kinda sounds like your motor is dying. Does it get warm when running?

 

[BirdRacer99]

Yes i did notice it gets kinda warm to the touch when i was testing it out after not running long, but it does say caution hot motor so i figure that was normal. I don't know what it felt like when it was working

 

[Mr_Wolf_Is_Innocent]

The esc sounds like it’s over powering the little tiny motor.. I’m not hugely clued up on these electronics, but that would be my concern. Other things to check is over tightened wheels could cause binding, pinion possibly rotating on shaft.. but listen to others advice before mine as I confess lipos etc are relatively new to me so I am still very much learning myself.


Element Sendero 1/10. Crawler/Trailer.
Scx24 crc. Crawler 1/24.
Wltoys a212. Shortcourse 1/24.
Wltoys k969. Drifty 1/28

 

[BirdRacer99]

I was messing around and was able to adapt a ps3 controller's rumble motor (very hacky). It spins twice as fast as the stock motor in it, but still running slowly.

Can anyone tell me if this is normal? The Driveshafts spin really fast but the wheels spin noticeably slower.

https://youtu.be/kVS5kcR7GkA

 

[Mr_Wolf_Is_Innocent]

Looking at the worms screw, I would think the drive shafts need to turn a few times (4-5ish) to rotate the wheels a single rotation, I am thinking this looks quite normal, but I am no expert, hopefully someone else will be able to confirm.


Element Sendero 1/10. Crawler/Trailer.
Scx24 crc. Crawler 1/24.
Wltoys a212. Shortcourse 1/24.
Wltoys k969. Drifty 1/28

 

[HumboldtEF]

Did you keep the stock radio? If so make sure you haven't moved the throttle trim switch, its marked L M H (low medium high) and controls how fast it will go.

Its normal for your driveshafts to spin faster than the tires because its a crawler and there is a lot more gear reduction compared to a fast RC.

 

[BirdRacer99]

No I'm using a spektrum radio now. It worked fine for a bit after the switch, not sure how long it lasted. When it happened i thought the battery was just dead but it wasn't.

I even tested by hooking up the battery directly to the motor and same issue.

Does anyone know the specs of the stock motor? I can't find the kV or rpm anywhere. I have a cheap tachometer and measured the stock one around 4,500 on 2s, and my ps3 motor at about 10,000 on 2s (battery directly to motor leads).

 

[HumboldtEF]

That does sound like it might be a bad motor. I dont know the KV but the stock motor is 88T

Check out this thread regarding motor replacements http://www.rccrawler.com/forum/micro-scale-rigs/616701-scx24-motor-upgrades.html

 

[BirdRacer99]

Now that I think of it, it's possible I damaged the motor because my favorite thing to do with it is rock the throttle back and forth really fast and make the car bounce in place. Switching from fwd/rev that quickly probably isn't good for it.

 

[BIGW0RM]

Now that I think of it, it's possible I damaged the motor because my favorite thing to do with it is rock the throttle back and forth really fast and make the car bounce in place. Switching from fwd/rev that quickly probably isn't good for it.

Not sure if this helps, but mine slowed down once and or would not go from forward to backward consistently.

In my situation, it was the worm gear. Once I swapped it out, it was back to normal.

Perhaps your F to R damaged the worm. I disconnected the axles from the transmission and turned them by hand to find the one that was sticking. When I put them back together, I slathered some marine grease all over the worm and havent had an issue since.

And mine has big heavy tires. 4 wheel steering, and max articulation. So Ive got a lot of stress on mine.

Hope you figure it out! Good news is, parts are cheap. "thumbsup"

 

[BirdRacer99]

Solved. I got an RGT 050 motor from asiatees and it's back to working again. Thanks everybody.

 

[microcrawlers]

be careful not to over-tighten the front wheel nuts. it will put the front end in a bind and cause your electronics to burn up

 

[Mr_Wolf_Is_Innocent]

be careful not to over-tighten the front wheel nuts. it will put the front end in a bind and cause your electronics to burn up

But check them regularly as they do come undone... (if using the millstones or and wideners)...


Element Sendero 1/10. Crawler/Trailer.
Scx24 crc. Crawler 1/24.
Wltoys a212. Shortcourse 1/24.
Wltoys k969. Drifty 1/28