FMS ROC Atlas 6x6

[spoo76]

I have both the SCX24 and Barrage motors. The shaft diameters are definitely different and the pinions not interchangeable.

The 0.3 pitch means nothing to me. I and use to 48p, 64, 72 used for slot cars, and I have seen that used for some RC gears.

1.5mm is the standard shaft diameter for those motors. I don't think they even commonly make 030 and 050 motors with a different shaft diameter than 1.5mm
I also have many Barrage and scx24 motors as well as other 030 and 050 motors, I also have lots of brass pinions all with 1.5mm holes and swapped the same pinions between motors and many others have as well. The actual official measurement of the gear teeth is called "mod 0.3" it's what it's sold as when listed. The equivalent in "pitch" is close but I don't think it's exact as it's a different way to measure and not even common or easy to find last I looked, either way if you want to find a pinion that works it's going to be "mod 0.3" with a 1.5mm motor shaft hole. Some have used 8t and have had them break. I prefer 9t for the smallest for a 1.5mm shaft as it has a little more material.

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[themountain]

0.3 modulus is a 85pitch
https://helihack.co.uk/modulus

But what about the spur gear ? Is there any chance to put a bigger than stock in it? I found this --> https://de.aliexpress.com/item/32861197222.html?spm=a2g0x.12010615.8148356.10.24745131DDrTI3
Would that fit ?

 

[shiggy]

1.5mm is the standard shaft diameter for those motors. I don't think they even commonly make 030 and 050 motors with a different shaft diameter than 1.5mm
I also have many Barrage and scx24 motors as well as other 030 and 050 motors, I also have lots of brass pinions all with 1.5mm holes and swapped the same pinions between motors and many others have as well. The actual official measurement of the gear teeth is called "mod 0.3" it's what it's sold as when listed. The equivalent in "pitch" is close but I don't think it's exact as it's a different way to measure and not even common or easy to find last I looked, either way if you want to find a pinion that works it's going to be "mod 0.3" with a 1.5mm motor shaft hole. Some have used 8t and have had them break. I prefer 9t for the smallest for a 1.5mm shaft as it has a little more material.

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By actual measure, Barrage shaft: 1.46mm. SCX24: 1.51mm
The SCX24 press-on pinion “fits” on the Barrage but just spins under power.

My main frustration is I can find ZERO aftermarket pinions.
Searches return nothing.
I really want a few 9-10t pinions and am coming up dry.

 

[Shape_Shifter]

I dont get email notifications anymore!!

Yes my pinions were from Poland microantrieb.com. I bought 10 of them a couple years ago. Very hard to find. Micro heli and slot car resources are sometimes effective sources.

If you get brass ones, make sure to heat them with a lighter before pressing them on, otherwise they could split because of the thin wall.

 

[Shape_Shifter]

Also, I think that spur gear may have come out of an SCX24

 

[Shape_Shifter]

Ok I have found the ultimate micro crawler gearbox setup. I used the stock Atlas gearbox and mated it to a divorced transfer case from an RGT Adventurer. The RGT transfer case is ~2.5:1 ratio so it basically cuts my final ratio in half. This is the perfect combination of low voltage torque and wheel speed IMO, and works excellent on the Atlas 6x6 and should work on any micro crawler.

To do it, I cut away some of the radio platform above the front axle to make room for the low platform I printed. The output shaft and drive dog cups from the RGT are 2mm instead of the 3mm like on most gearboxes. Instead of drilling out one of the cups to 3mm, I just modeled one with a 3mm hole with a D flat then printed it. Also printed a new radio platform that sits between the motor and the battery tray.

Ill try to get some video of the crawl speed.

 

[Shape_Shifter]

Short crawling video.

https://photos.app.goo.gl/XfyrKLLcKVUF4dh77

 

[shiggy]

Also, I think that spur gear may have come out of an SCX24

I found what appear to be the same spur gear as the SCX24 at panda hobby. Can get almost every part of the Panda individually. Not expensive—mostly.

Also got a couple of RC4WD FF-030 micro motors with 10t brass pinions.

 

[shiggy]

Ok I have found the ultimate micro crawler gearbox setup. I used the stock Atlas gearbox and mated it to a divorced transfer case from an RGT Adventurer. The RGT transfer case is ~2.5:1 ratio so it basically cuts my final ratio in half. This is the perfect combination of low voltage torque and wheel speed IMO, and works excellent on the Atlas 6x6 and should work on any micro crawler.

To do it, I cut away some of the radio platform above the front axle to make room for the low platform I printed. The output shaft and drive dog cups from the RGT are 2mm instead of the 3mm like on most gearboxes. Instead of drilling out one of the cups to 3mm, I just modeled one with a 3mm hole with a D flat then printed it. Also printed a new radio platform that sits between the motor and the battery tray.

Ill try to get some video of the crawl speed.

Interesting.
Not sure what I am looking at without a pic of the stock truck for comparison.

 

[Shape_Shifter]

I found what appear to be the same spur gear as the SCX24 at panda hobby. Can get almost every part of the Panda individually. Not expensive—mostly.

Also got a couple of RC4WD FF-030 micro motors with 10t brass pinions.

Those FF-030 motors are great for 1/24 stuff but will struggle with the 6x6. Good to have for other projects though.

 

[Shape_Shifter]

Interesting.
Not sure what I am looking at without a pic of the stock truck for comparison.

Good point. That's because my installation is so awesome, it looks stock ;-):ror:


The Atlas is basically a CR-18 with an extra axle. I didnt take any "before" pics but if you look for Spoo's CR-18 threads, Ill bet he has some stock pics.

 

[shiggy]

Those FF-030 motors are great for 1/24 stuff but will struggle with the 6x6. Good to have for other projects though.

Mainly interested in the 10t pinion.

 

[spoo76]

The Atlas is basically a CR-18 with an extra axle. I didnt take any "before" pics but if you look for Spoo's CR-18 threads, Ill bet he has some stock pics.

Awesome job with the motor setup!
Here are some photos BTW.

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[shiggy]

Good point. That's because my installation is so awesome, it looks stock ;-):ror:


The Atlas is basically a CR-18 with an extra axle. I didnt take any "before" pics but if you look for Spoo's CR-18 threads, Ill bet he has some stock pics.

So, did you move the stock transmission/motor to the front and install the “new” transfer case in the middle?

 

[Shape_Shifter]

So, did you move the stock transmission/motor to the front and install the “new” transfer case in the middle?

Yes, that is exactly what I did. The new transfer case mount holes are the same as the stock motor/tranny so it bolts right up. Its an easy way to "bolt on" higher ratio gears.

 

[shiggy]

Yes, that is exactly what I did. The new transfer case mount holes are the same as the stock motor/tranny so it bolts right up. Its an easy way to "bolt on" higher ratio gears.

Higher ratios? Faster?
More torque/slower is lower.

 

[Shape_Shifter]

Higher ratios? Faster?
More torque/slower is lower.

No, a higher ratio is slower and has more torque. For example: 4:1 is a high ratio, but slower - 1:1 is a low ratio, but faster.



When people talking about drive trains use the term "lower gears" they actually mean a higher gear ratio.

 

[shiggy]

No, a higher ratio is slower and has more torque. For example: 4:1 is a high ratio, but slower - 1:1 is a low ratio, but faster.



When people talking about drive trains use the term "lower gears" they actually mean a higher gear ratio.

You have that backwards 4:1 is low ratio (or a short gear) because the wheels are spinning at a lower RPM than the motor. 4 revs input = 1 output.
1:4 would be high, with output four times faster than input.

In a full size vehicle first gear is “low” gear. Fifth gear is “high”.

You gear down to go slower.
Gear up to go faster.

 

[Shape_Shifter]

You have that backwards 4:1 is low ratio (or a short gear) because the wheels are spinning at a lower RPM than the motor. 4 revs input = 1 output.
1:4 would be high, with output four times faster than input.

In a full size vehicle first gear is “low” gear. Fifth gear is “high”.

You gear down to go slower.
Gear up to go faster.

No. In math, science, and industry, an example of a high ratio would be 20:1


As a rule - if the difference between the two numbers is large, it is considered a high ratio. 4:1 is a higher ratio than 1:1.


As I said, above, "When people talking about drive trains use the term "lower gears" they actually mean a higher gear ratio." Just because 1st gear (1) is a lower number than 5th gear (5), doesn't mean the ratio of the actual gears in the transmission is lower in 1st gear.









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[Shape_Shifter]