JUMPINATOR II | swappable batteries | lightweight MTB | HAERO | MBS | APEX

rich · October 10, 2019, 10:41pm

This is the evolution of the Jumpinator, a board made for fun in skate and dirt parks.

The goal is minimal weight for maximum air and easy maneuverability.

I had to deal with bottoming out Trampa decks while landing so the consequence was to switch to the ultra-stiff DW II deck. Because the deck was out of stock everywhere I decided to buy the complete board and switch to E-Toxx Mini Helical Drives. My wallet is not amused but I am twice .

Board (weight: 7.66 kg / 16.89lb):
DW II deck
Matrix II metal trucks
F5 bindings and heelstraps
Rockstar II hubs
8” T1 tires

Mechanics (weight: tba):
E-Toxx mini helical drive 8T/40T 1:5 gearing

Electronics, motors & battery (weight: 3.3 kg / 7.28 lb):
Flipsky V4.12
Modified 6364 150kv motors
3x4s 30C 5Ah Zippy lipos
12s BMS 60A (120A peak)
VX1 remote

Final weight approx. 12kg / 26.5 lb

This is the first and last time you see the board so fresh and clean

There are some things to prepare.

MBS doesn’t use bearing spacers but I prefer to have some. So time for old school work with saw and sandpaper, the spacers ended between 22.2mm and 22.5mm depending on the hub.

The countersink screws of the bindings are not flush with the deck and stick out a bit. I would damage them so better to fix this now.

Due to the drives I need to make cut outs at the tips of the deck or if I’m lazy at least at the rear. For now I’m just playing around with cut newspaper to find a nice shape.

Due to the concave of the deck it’s not that easy to mount enclosures compared to flat Trampa decks.

Right now the electronics look like this but I have to replace the ABS sheet and type of mounting for the DW II deck.

Also I would like to have an easy switchable battery (enclosure) without velcro, some kind of quick-action locking system…. Also thinking about better protection than the 0.04mm silicone cover only. But I guess i ghettomount it somehow before the winter starts otherwise it would take too long .

That’s it for now, I’m very excited to pick up the parcel from E-toxx which is waiting at the post office. Unfortunately it’s almost 1am here so I have to wait (and probably sleep) a couple of hours…

malJohann · October 11, 2019, 2:12am

Contact @Duffman, he might have something for you.

rich · October 11, 2019, 8:49pm

That’s a very smart solution I’m just not a friend of velcro
I was thinking about to mount a plate to the deck with 4x threaded inserts and then mount the rest to the plate somehow.

I got it
From E-Toxx with love

The mini drive looks so small compared to the maxi drive

On special request I got also some 7075 aluminium plates for the maxi drive to replace the steel ones. Time for some comparison pics.

Size comparison of mini drive and 66T HTD5M pulley, great ground clearance.

Also not listed in the E-Toxx shop but I could order a custom made 8T helical with 10mm inner diameter

The last 2-3mm are 8mm bore, it’s not possible to make it 10mm there. This is no problem for motor shafts up to 27mm. In my case it’s 30mm. So I have to cut the shafts or use this motor spacer which is made for Flipsky or TB motors or just too long shafts

I think I have some things to assemble

Pedrodemio · October 11, 2019, 8:52pm

What about Velcro straps? I have used them a lot in rc cars and the battery wouldn’t move

Actually I used both, Velcro on the bottom and the strap looping around

rich · October 11, 2019, 9:06pm

I could try that with velcro plus straps but mounted to the plate and not to the deck.

I’m also curious how long the Matrix II trucks last or until the axles bend.
From jumping I’ve bent the solid steel axles of the Trampa Infinity trucks

Today I had a short but crazy ride with the dirt machine and trampinated the front vertigo truck to the fullest The hanger plus one axle is bent. R.I.P. I killed 5 trucks within 1 year so far, is that normal? .

malJohann · October 11, 2019, 9:11pm

Try @Kaly trucks, they’re CNC not cast.

rich · October 11, 2019, 9:40pm

I’m sure they are solid but the 10mm axle maybe not for heavy abuse and jumping.

@Kaly was just surfing on your page, great products btw
I recognized the bearings which you sell and ship from USA are made in Austria.

BEARING_USA

I live in Austria but when I would buy the same bearings here they are much more expensive and made in USA

BEARING_AT

Lee_Wright · October 11, 2019, 9:50pm

Rich, do you have a 3d printer? I think you do but cant remember, anyways if you dont I could knock you something up in nylon if you have an idea, would be super light and super strong at the same time

Andy87 · October 11, 2019, 9:52pm

I think he doesn’t have a 3d printer as he last time was crying that he need to find some hardware solution for the phase wire routing instead of just printing something

rich · October 11, 2019, 10:03pm

I cry a lot because of no 3d printer

@Lee_Wright thanks a lot for your offer, I’ll let you know if I have some ideas .

Lee_Wright · October 12, 2019, 12:01am

What exact batteries are you using bro? and do you use an onboard BMS or BMS is external?

edit, duh I could just re-read the thread. I have an idea - I will try and design something for you this weekend. you want to keep all the elctronics as they are but just be able to change the batteries easily right?

rich · October 12, 2019, 2:17pm

The main first world problem is that I don’t really know the needed dimensions yet. The lipos won’t last long so I think next is 12s2p of 40T or 12s3p of VTC6, in best case 2 identical packs. Also I have to add heatsinks to the V4.12 and lay them beside and not one above the other. I had massive problems with thermal cut-offs.

So I don’t even know the size for electronics.

If I do it old-school it would be something like this:
Due to the concave I thought about a plate like this bolted to the deck

and then 2 separate enclosures, a smaller one for electronics on the right side (just as an example), bigger enclosure with battery on the left side. Could be velcro and straps.

But I’m sure there are better solutions like slots in the plate where you can slide in the top enclosures or some other future shit.

Also I have no idea where to drill holes for the inserts when I don’t know how I mount everything. That was originally the reason for using a plate, the holes for mounting to the deck would stay the same whereat all the rest can change.

Pedrodemio · October 12, 2019, 2:23pm

For securing it, you could have each battery mounted in its own plate, and a board plate mounted using longboard bushings like Trampa does

For locking the battery plate to the board one you would use Dzus (the clips used to secure lots of race cars panels)

Venom121212 · October 12, 2019, 3:12pm

Watch your back Rich, I have all the parts coming today for an ULTRA LIGHTWEIGHT _{^non-electric} JUMPER!

Disc brakes and all

Perhaps with 1/10th of the weight, I will finally be able to achieve 1/3rd of your height

Lee_Wright · October 12, 2019, 6:20pm

Let me know what battery for sure bro, I’ll draw you up my idea and see what you think. I’ll PM you this week

brown5tick · October 13, 2019, 12:45pm

Following your lead here, @rich

glyphiks · October 13, 2019, 1:09pm

have you seen how Dylan Warren rides? I would think that these trucks would be exceptional for the use case!

This is the cut I chose for mine, nice, easy and clean.

rich · October 13, 2019, 5:50pm

Good idea, will take a closer look…

Have fun!
Do you plan to electrify it and lose the word “ultra”?

Yes and I remember when he snapped a truck
This video made me want the deck, it doesn’t flex at all when landing

Today I did some mock ups and measured different parts before I mount everything. On the left side MBS Rockstar II hub, on the right side Trampa Superstar.

The Superstar hub would need a 4mm spacer on the extension.

Here a comparison with mounted E-Toxx hub adapters

The superstar takes less space on the axle

despite the inner width is bigger (about 3mm)

Looks great! Also the new foot pedals…
I thought I have to cut even more to have enough clearance for the drive train.

Then I did some tests

didn’t expect that.
This is the clearance when the distance between motor plate and tip of the axle is 68mm and the helical on the motor 28mm. There is about 5mm distance to the hanger on full tilt when it touches the motor plate. This could be enough in real life. If I cut just a liiiiitle bit at the edge I could touch the hanger.

glyphiks · October 13, 2019, 6:55pm

It was the motor that got in the way for me.

rich · October 13, 2019, 7:07pm

Thank you very much you ruined my peaceful sunday evening

Unfortunately you are right, I checked it again. The distance to the motor is the same as to the hanger right now (5mm). So if I remove a small piece of the deck then it touches the hanger plus the motor.

Again will you accept my thanks for pointing this out?