20SSS 2ST BRO : a 20S SSS inrunner 2Stage reduction build (2023 BOTY Candidate Update)

The battery box : [Turnigy Transmitter Bag / Carrying Case]



The ESC box : [OVERION Speedbox V23 & MakerX Go-FOC D100S]

The power cable harness :

Fuse upgrade :

The grip pads : [Treadmaster]

The motors : [SSS 56123 360KV]


Drivetrain : [E-TOXX STEALTH420 with 1/15.625 2Stage gear drive and ]


Lipos : [20S / 4x Gens ace 5800mAh 60C 18.5V 5S1P Lipo Battery Pack with XT90 plug]



HFI settings :


Wow that gear drive ratio is insane haha


anything with etoxx gear in it needs to be flagged as NSFW :drooling_face:
and you running hfi?? my inrunners hated anything but encoders, but i didn’t tune hfi

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What is this 2 stage drive what does it mean!? :exploding_head:


a gear ratio feeding another gear ratio
1:2 with an output into a 1:5 makes a 1:10 etc


Yeah, one gear drive on another gear drive : first is 8/25 and second is 8/40.

1/((8/25)*(8/40)) = 15.625

Yes I run HFI. I have used this tutorial :

(Jeffrey Friesen the Unity then Stormcore guy)

I haven’t ride it yet! I wonder if I will get a better experience than with my 12S 80100 10/35 build which is my best e-mountainboard.


Its so… wide


Girth matters more than length Jesse… we know this.


That is the one Musk will use on Mars.

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That has to be pure insanity. Amazing build dude.

First ride today!

Opinion about SSS 56123 inrunner high KV / high gear ratio :

Compared to my 12S 80100 130KV outrunner 10/35 build :

  • The SSS set-sup feels less powerful, less beasty and it delivers the power more smoothly.
  • The SSS set-up eats more power in the same time : 27.0 Wh/km compared to 22.7 Wh/km for the same kind of travel.
  • The temperature of the SSS inrunners was a higher than the temperature of the 80100 outrunners, that are bigger and heavier (80100 : 1960 gr / 56123 : 1330 gr).
  • A lot of ABS_OVER_CURRENT faults with the 56123 on the ESC that manage the interior wheel when turning 180° off-road : I think that because of wide hangers this wheel gets all the grip work and 280A as Absolute Maximum Current is not enough ; current is at this time from 285 to 305 A on the motor involved.

Opinion about MakerX D100S :

  • ZERO issue at 20S. I don’t have the low speed braking issue which has been reported by some folks.
  • Max current is weirdly low (43.5 A) but I was limited by the ABS_OVER_CURRENT faults off-road. I usually take 75-90 max battery amps with my 12S 80100 build.
  • The ESC keeps very cool : max 31°C (considering it’s about 11°C this afternoon).

Opinion about E-TOXX STEALTH420 double kingpin trucks :

These are the best trucks I have ever tried. I have rode Trampa VERTIGO trucks with springs or barrels, MBS Matrix 2 and Trampa IR trucks.
They have the best stability/turnability ratio ever. Turning radius is stupid short. I have to admit I may have forgotten to tighten something on the rear : :sweat_smile:

But I was yet able to go up to 50 km/h like that, without fear!
The only possible caveat is the width of them, and you have to take care about available room between two obstacles to make sure one wheel will not strike one of them.

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hold up. how is it higher, i could barely break 40C on 56123 230kv 1:5 9inch mudpluggers
135A each side

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It was not very hot, maybe 50°C (because I could hold the whole can in my hand). But the 80100 outrunner is cooler for the same kind of trip.

My 80100 build is the only one I can ride in summer with no issue when it’s very hot outside.

Maybe it’s possible that higher KV motor is less efficient. It would be interesting to determine if higher KV with higher gear ratio worths it. It’s way more simplier (and cheaper) to have a 1:5 chain transmission than a 1:15.625 2stage gear drive one.

@ Pickled_Monkey How did you set Absolute Maximum Current? (and which ESC?)

if your comparing can temperature, outrunners sators are waaay hotter then the can temperature
i was running a spintend ubox v2 absolute max was 165a i believe, my main bottle neck was the vesc would hit 80c after 25min ish and the only time it didn’t was when it was -7c outside and the heatsink was exposed directly upwards into the wind

It could also be that you’re simply revving the inrunners up so much higher that the iron losses are significant.

Another for a member has had an underwhelming thermal experience with large, high revving motors on a race board this year, but I can’t remember who at the moment.

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2nd ride today :

Setting Absolute Maximum Current from 280 to 340A allow me to lower the ABS_OVER_CURRENT faults number from 11 to 1 (344.5A).

Always the same motor, in the same conditions (when turning tight on dirt).

What I don’t understand is where are the 344.5A or the filtered 152.6A on the picture!?


Setting the Throttle Curve to +10% and the thing has now more puch! :japanese_ogre:

Those E-TOXX truck are magical! It’s so easy to turn with them that I wonder if I will remain able to turn with other trucks!


That wasn’t me, but i do have a board with very high RPM outrunners and i can confirm, they run hot.

205kv 6485 at 18S, 4:1 reduction on thane. The motors, even just cruising at speed and not really being aggressive will run VERY hot as a result on the constant high rpm.

I don’t know if it’s as bad with inrunners as outrunners, but i suspect that’s a pretty big factor here.

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What fw ver?

“6.02” custom firmware downloaded here :

(but Minnie tells me FW 6.2 with Metr Pro)

Actually, today with same exterior temperature motors were less hot. I think on first ride I tested HFI with too many start up from still (and HFI runs good with my settings). Even on bench, HFI experiments make the motor quite hot.
Also, as @Pickled_Monkey said, on inrunners copper windings touch the can whereas on outrunners windings are on the strator. So, comparing by touching is a bit awkward.

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