Tantrum build: 210 dualities, tangent deck, 18s4p rs50, rs125s, d100s, custom brackets, BOTY 2026!!!

Pecos · November 8, 2025, 5:47am

Goal of this build is to play around with this tangent deck more than anything. really enjoy riding this thing analog and wanted to put some motors on it without changing the feel too much. how light and nimble it feels is a part of its charm and i want to preserve as much of that as possible. But i kept changing what i wanted to do with it. At first i just wanted to stealth some hubs on it and make a medium range commuter, then i got my sportster build second hand and tuned that up how i like and don’t want to double up in the quiver, I have a lot of boards and have been selling or trading off the overlapping ones that just don’t get ridden enough. It would do a great job i think in that role but it also has so much potential to also explore.

Then i saw what @poastoast did to his tangent and the idea for the build kept changing but was starting to jell a little more. What about a mid range belt board on regular urethane wheels and keeping it super push able? I’ve been having so much fun on the sportster hub build trying to slide and riding it at the edge of traction I’m getting drv faults. Then my mind flips again and I’m planning something fast and long range again but i don’t want a top box and i don’t want a fat belly enclosure. i want to keep it low and as light as i can get away with. Then im searching for ronin trucks and can’t find a thing for that duality/singularity feel in a smaller form factor.

if i could build from unobtanium i wanted to use Ronin trucks but up to a 10mm axle, custom shorter brackets as the plastic tangent ones are a bit too flexy and the length of the 30mm idea brackets is just toooooo long. 6465 Reachers on a gear drive that will run thane and cram a 16s battery underslung at 2p or maybe 3p with some 105mm thanes.

then i saw dualities in 210s?!?! messaged @Titoxd1000 and got a set from his next batch for a flat deck. didn’t realize the width of the baseplate wouldn’t really work for drop through brackets… but brackets cant be that hard to design right?

im on version 5 and had to learn fusion 360 - it’s getting better but the tldr is a flat bracket sucks, the idea brackets are too long and too deep and would need some modifications to work drop through anyway. 20mm drop seems perfect but the 30mm and dropped through is too low (bushings for reference) once i account for the enclosure. Printing some 20mm ones now and ill see how they do

20mm bracket for dualities

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Pecos · November 8, 2025, 5:48am

Complete! OK so BOTY Nomination! (Edit: BOTY win!?!? Thanks everyone for the love!) hell ya. really appreciate the love I’m getting on this build. biggest contributor to the success of the Tantrum and the refinement iv been able to shoe horn into it has been the rain. This winter has had a really good mix of rain, showers, storms, atmospheric rivers and a small countable number of sunny days mixed in to give me the time to just keep plugging away on this guy.

final spec (as of feb 1 2026) (wall of text will get pics and hidden details added later)

Loaded tangent deck: defanged for goofy riding - absolutely routed within an inch of its life - skinned with one layer of Kevlar/CF on the topside and one layer top and bottom CF twill with some shiny red tinsel in there. original had a little bounce and was nice and reactive - mid process it was so soft and flexy from all the material i removed from the bottom - now its very stiff but has a good pop when you push it hard.

210 Dualities: just absolutely phenomenal trucks. New 95a tpu lean stoppers at 7mm. 95a wfb riptide up front and the stock green krank in the back.

Custom Brackets: 10mm drop, 304 stainless with a gloss red paint.

Tomiboi enclosure: Poast’s custom tangent enclosure, 10mm clear TPU gasket with butyl seal to the deck and just a smidge of foam on the enclosure side. super bright led’s imbedded and glued to the interior running of a generic Bluetooth driver with enough modes to keep me happy while i work on something custom

Tomiboi single front foot hook: custom tpu spacer to get it to the right position without pushing the front foot position back. top charging xt60 port. usb 5v whip attached under the front edge for remote/phone/whatever slow charging.

Rear wedge and wire management: kept biting my foot so the wedge gives me that feedback to help keep my rear foot in a good position. remade it a million times and this one wedge has taught me fusion. still a work in progress. added concealed power button.

6455 170kv SKP Reachers: picked up second hand on here. using tito’s short motor mounts and belts. currently settled on 15/45 and fits 340mm belts added custom red tpu bump guards for now…

radium rs125 mediums: was messing with repainting them but ended up going back to black and yellow.

RS50 18s4p diy battery: Copper and over built - should be good for somewhere around 200a cont and short duration pulls over 300a. Oversized 50a JBD smart BMS. charging at 30a had good thermals so feel comfortable saying this can regularly charge at 20a. slow charge about 8a.

D100s on 6.06FW: smart reverse is fixed, 6.06 seems like the most stable and smooth vesc interface I’ve ever used. knock on wood - haven’t cussed out vedder once programming this thing. USB extension added to the rear lip of the deck so i don’t have to open up to adjust settings i don’t feel comfortable doing over Bluetooth.

VX4 PRO remote: long term this will get replaced. grip and thumbwheel just don’t work for me. they work great but i have hand issues and flipsky trust issues. Looking for another trigger and hoping the GB will slide in here pending development.

Mini for Bluetooth and logging - stolen from my sportster - wont get a dedicated one unless Cheeto taxes go away as i had to pay 250 to get it out of customs. fuck trump and his pedo cronies - if it was just a tariff it’d be fine but annoying - but there is a depth of abhorrent disgust i have for that entire group of self enriching pedo scammers i wont get into further. manus haec inimica tyrannis ense petit placidam sub libertate quietem

some pics before i do more formatting:

Pecos · November 8, 2025, 5:59am

Pecos · November 8, 2025, 6:42am

Ok so it doesn’t look like i added 10mm of clearance but i did and i like it. Part of it is bad photography on my part and also partially my impatience. I printed these from American cheese which if you’re familiar has no character and therefore no spine so is sagging just a smidge. When i take some if the weight off it looks like what i want so im gonna roll with it. A few tweaks and off the the water jet.

Speaking of cheese:

Printed them so thin they don’t want to hold a screw, but like grandma used to say “if you can’t screw well, screw a lot”

Pecos · November 8, 2025, 2:34pm

Decided im gonna do one last prototype just to be sure. Upgraded from cheese filament to petg with reasonable strength settings and tuned the spacer sizing, added all my drill holes or pilot holes so it’s easier to center it all up And started the printer before im off to work.

Saturday work

also messed up my pulley and belt order lol. Ordered one of each…

More on the way soon lol. Using the force calculator i settled on around 16t. Oh ya, drive train:

So ive got some 6455 skp reachers sitting on the shelf so im gonna use those for now. They’re 175ish kv so not ideal but workable. Then im using the 45t wheel pulley for the rs125s

that puts me at 90mm center center on tito’s motor mounts with 15t/45t and a 335mm belt. also snapped up some 17t pulleys and have some 340mm belts on the way to try some different arrangements. putting it all into the calculator its showing 419 newtons… so i may have to upsize my motors if it doesn’t punch like i want. This thing needs to be able to do a wheelie. Also why im trying to keep the pully on the larger tooth count to limit slipping. depending on how it shakes out i may put in a longer motor mount so i can add an idler/tensioner to keep good tooth engagement. i hate slip and want to eliminate as much as possible.

cells showed up for the 18s3p and i messed around with configurations and possibly lower (16s) voltage to get more into the shallow enclosure without a gasket… but im also toying with the idea of a clear tpu gasket (6-8mm) and putting led lighting into it. i think i can get by without a gasket but it may just be easier and neater to use one if i think on it enough. not committed to the voltage yet but i dont want to reduce the cell count. range is already gonna be limited and i don’t want to reduce it below a solid 17 miles of range. ideally i would figure out a way to get 22miles of range but i just dont think i can cram it in there and refuse to do a top box. i just love walking around on my deck and hate being locked into one stance or not being able to squat down low on my boards.

Pecos · November 8, 2025, 2:41pm

Dinnye · November 8, 2025, 2:42pm

If you want to be able to push the board easily, this is the way to go! Added benefit is that with a bit of luck with an idler system you might end up with a belt bigger than the wheel to allow for 10 second tool less belt changes

Pecos · November 8, 2025, 3:24pm

Are you reading my mind!?! Get out of my head!

The parsec drive train lives rent free in my head dude. The child of the mach1 and the parsec aero pro is my previously unspoken target.

Dinnye · November 8, 2025, 4:05pm

I had that on my board in 2022!

Best feature ever if you go for belt drive

MichaelWA · November 8, 2025, 10:27pm

What mounts has a built in idler?
I know Mboard, BN and IDEA.

glyphiks · November 8, 2025, 10:35pm

All you really need is a drill, some nuts and bolts and some bearings…

rafaelinmissouri · November 8, 2025, 10:45pm

I have a few belt set ups going these days and no idlers…

Idlers can be good but also finecky…

Pecos · November 9, 2025, 1:17am

I think if the idler isn’t really straight it can push the belt off. Too much tension can make it kinda useless too. There is a fine line

MichaelWA · November 9, 2025, 1:38am

I do want something more polished.

Edit: I’m lazy.

Pecos · November 9, 2025, 1:47am

I have some bn mounts with idlers, only matrix 2 clamps so id have to make something for them. Might grab those matrix 3s back from you at some point and test something out

Pecos · November 9, 2025, 5:07pm

Ok, finished tweaking the model and added all the holes for the attachment points to the trucks and deck and printed it in petg (clear because thats what i had loaded) so it will be a little stiffer. Did a reasonable amount of infill and perimeters because I don’t think ill need to do more prints.

Assembly done and checked the wheel bite. Even when I remove the lean stoppers… because i know i will, i still have good clearance to the deck.

Worst case ill have a 10mm gasket so with the enclosure resting on the brackets it gives a good approximation of my worst case clearance and im sitting about 40mm minimum at neutral lean amd about 12mm to the corner on max lean. I can live with this. I don’t want the deck any higher as it’s right at bottom of deck at top of hanger level. High but push able

Pecos · November 9, 2025, 5:20pm

Adding to the list of possibilities, after i get actual brackets made up so i can get a proper feel for how it sits and moves under my feet im think i might need to make the front toe and rear heel lip on the deck a little less aggressive.

The feel and feedback from the “sneer “ corners is good but my feet are just a little bigger than it fits perfectly. Not going to do anything until i can properly stand on it but i see it in my future.

Also plan on adding a foot stop that will attach to the spacer on the bracket to help lock in. Im thinking of something like the pads on an euc or like the hooks used on one wheels that are big tpu assemblies that partially go over the foot. Like the tomiboi hooks but a more rigid but slightly conforming… something

Pecos · November 11, 2025, 6:59pm

Playing with the motors and the 6455s look nice but I worry about having enough amps on them and at 18s I don’t know if they are the newest version that doesn’t have issues at high voltage or not… just checking on things and i could fit up to 6495s if it comes to that. 6485s would be plenty and a 70ish motor would probably be plenty. Good to have options if it comes to it but gonna run these first.

Kinda wish the wire exit of the motor was 45° from where it is. Might play with it and see what i can do

anyone know how to determine the version of reachers? Im going to start engraving it on the mount holes on my motors lol

JustNeL · November 11, 2025, 7:20pm

I got a pair that have less than 50 miles on them and worry about the same but on 12S. .. Im a big dude 6’1 230-240lbs.

I have 6485 on my flux and i fly with those. Will have to test them

Dinnye · November 11, 2025, 7:20pm

5 vent holes (+1 for cable) is v6 or newer, 3 vent holes (+1 for cable) is v5.

Pretty sure only Radium ones can be newer than v6 but don’t quote me on that.

The 75s I have on my mountainboard pack plenty of punch! I’m running them at 21S 175 ish KV 150A phase each on 1:7 gearing 8.5” tire and it gives a 38mph top end with insane punch. Suprisingly enough doesn’t melt from top speed runs either though wasn’t really riding in super hot weather.