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Rock Crawlers For those Rock crawling, stone sliding, body scratching, articulation crackheads; this place is for you!


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  #1  
Old 09-25-2019, 03:33 PM
Tommygunn Tommygunn is offline
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Default Strange SCX10 type drivetrain phenomenon!

I have an SCX10 esque vehicle, think all metal (Aliexpress) Chinesium, which is properly shimmed and buttery smooth. However, today I have received a 55T motor and I've been busy messing.

I noticed, after removing the spur gear and the attached clutch/friction pad, that when I rotated the opposing alloy friction disc it was buttery smooth but in the other direction there was resistance. By resistance I don't mean friction but more like magnetic or gravitational, if you get my meaning.
I was using the pad of my finger on the edge of the friction plate and it was not a problem in the one direction but slipped in the other, regardless of pressure.

I'll say again, everything is shimmed to perfection but what comes to mind is the differentials and the direction the gears rotate.

Is there some sort of mechanical phenomenon that produces this? What is also strange, is that if I lift the vehicle off of its tyres the buttery smooth prefection is the same in both directions of drivetrain rotation.

Any ideas?

Tom.
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  #2  
Old 09-25-2019, 06:27 PM
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frizzen frizzen is offline
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Good job going through a chinese truck and getting it shimmed to perfection and buttery smooth. It sounds to me more like the gears need time for their mesh to wear in. Probably run a couple packs through it and recheck.

Also might want to scuff up the friction surfaces on your slipper clutch while its apart.

Or being chinesieum, it could have an off spec bearing trying to act more like a One-Way beaing.
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Old 09-26-2019, 01:31 AM
Tommygunn Tommygunn is offline
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I've just experimented with the orientation of the gearbox/motor as a process of elimination. I've been running it with the gearbox/motor flipped 180 to counter torque twist(spur gear to the front) so I reverted it to its original, factory setup, with the spur to the rear.
The effect is the same in all ways but in the opposite direction!

The gearbox, on its own, was slick and equal in all directions be it spun from the input shaft or output. Therefore, the only thing left are the axles which have not changed orientation.

I also hand tested the axles/diffs in each direction, via both the drives shafts and wheels, and they too are perfect and free, needing only the slightest effort to move and keep moving.

How can this effect be explained if it is now in the oppposite direction?

Tom.

Last edited by Tommygunn : 09-26-2019 at 01:57 AM.
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Old 09-26-2019, 01:49 AM
Tommygunn Tommygunn is offline
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I just tried the gearbox connecting each axle individually and then followed by flipping the gearbox and repeating.
The effect is the same on both individual axles and with the flip of the gearbox the effect reverses.
Really weird.

Tom.
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