Haha sorry bro!

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Same even with the extender kit ^^

Like that it’s just on time

(I have to go with Rockstar2 too … would want 5star but …)


Nah I’m going to leave this one manual. It’s on a pretty junior setup so I’m going to let some of the older kids in the neighborhood downhill it and tow them behind my golf cart for practice. @sender currently has my DW2 deck. Going to rework my mtb over the winter and hopefully be ready come spring.


Finally received the bearings to assemble the fixed motor and everything works

After adding a second flatspot to the motor shaft and gluing it to the can on the first motor I wanted to upgrade the second motor the same way. Well unfortunately 1 bolt got totally stripped despite using wera hex plus tools and using a blow torch before. Gluing the bolts with Loctite 638 was a bad idea.

So I had to saw a groove for a flat screwdriver but there was no space for any tools except this tiny saw blade and later a bigger blade.

Then I heated the area with the small blow torch again aaaaaand snap!

OK let’s try it deeper in the thread and blow torch again… zing!

This was the very last groove and try aaaand the blow torch…

aaaand snap!

After spending many hours the glorious result is a can full of metal chips and that’s it :partying_face:.

At least something different works, made 4,5mm spacer for the truck extensions so I can mount Superstar hubs as well plus bearing spacer.


Oh man that’s rough


Yeah sometimes it’s FIY (fuck it yourself) instead of DIY :man_shrugging:
I guess I glue the gear and wait until the shaft starts shifting/moving (hopefully not at the first ride) then I can remove it and do a ghetto surgery.

Time to move on…
Curved cut-outs look sick but are tricky without the right tools (or would take forever) so why not going the easy route with a straight cut, made a simple template.

started with the small japanese saw

better with the big one, looks like a weapon :laughing:

Well my arm hurts but I’m satisfied with the result


Super cleanly done bud. Did you have to go over the cut edge in black again or did it stay black?

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It looks like this before painting with permanent marker :grin:

and the build lost some weight


I used this

Much easier!


It’s always the same, you think you can do things fast but in the end it takes forever. I’m sure you know this feeling :laughing:.

First I had to shorten the 30mm shafts

After cutting several shafts with the dremel I found a better technique this time for getting straight cuts. The bell inside a bag is much easier to work with instead of the whole motor with wires. Also you can rotate the bell if you got askew and get a new chance.

On the left side you can see the slice is askew but on the motor side perfectly straight.

After grinding the edges I dremeled a (ugly) flatspot for the grub screw of the helical.

Shaft length check succeeded

Sanding the shafts and inside the helical with 80 grit sandpaper

Time for gluing
The clamps are perfect for holding the motor without any axial backlash (both motors had between 0.5 and 1mm). If you have backlash the motors will rattle badly on every bump or offroad and move left and right when accelerating/braking because of the side load of helicals.

Marked the flat spot for easy positioning of the threaded hole for the grub screw.

Then glued them with Loctite 638 and pressed them hard against the washers for some minutes. This way there is no chance for any gap and the gear sits straight on the shaft. If I would use the grub screw now this wouldn’t be the case.

It’s done, after 24 hours cure time I’ll add the grub screws with Loctite 243 and let it cure for another 48 hours.

I was thinking about a solution for precise mounting of the motor mount and went with ABS sheets between mount and wheel helical.

In the end I used the 2mm ABS sheet plus 0.5mm shrink tube to get the perfect spacing when the helical has 28mm distance to the motor.

This is very covinient for the future. When I change motors it’s always 28mm distance. When I kill the rear truck I buy a new and use the ABS sheet and heat shrink for mounting the drive train.

On my regular MTB I had to re-mount the drives several times because of killed trucks. It’s not fun to find the correct position on the hanger with mounted motor and glued helical. Next is to use the same technique with ABS sheet spacer there, too. Very soon I can do it because I’ve bent the 12mm solid axle and actually waiting for a new rear hanger.

And this is the max. tilt before the motor would hit the deck, that should be enough.

Have a nice day :grin:


What BMS are you using?

Are you using a balance charger to charge?

I’m using this 12S BMS but it’s quite large (95mm * 87mm * 10mm)

For charging you need a Li-ion charger (CC/CV), I have this 4A charger for 12s (50.4V)
It’s small and has a fan so it stays cool. The cheaper plastic chargers like 1A-3A get very hot. Basically you connect a charge port to the BMS (-) and battery (+) where you plug the charger, it’s very convenient. Balancing is done by BMS.

I’m also searching for a smaller 12 BMS which can be used for discharge. All the “small” BMS for charging only (bypassed) are just more slim but not smaller that’s why I stay with discharge BMS for now. From my experience a “real continious” 60A BMS is really enough even when you pull 100A from time to time. On my MTB I use a 50A BMS from Bestech and pull 100A, no problem and it stays cool. It would cut-off at 110-120A.

Here some alternative 12s BMS which would work and are smaller than mine.

40A cont./100A max. for smaller packs like 3-4p
there’s also a 21A version available but same size
size: 124mm * 60mm * 9.3mm

Sealed BMS
60A cont./180A max. size: 80mm * 65mm * 12mm
25-35A size: 73mm * 61mm * 09mm

Smart 60A BMS
size: 108mm * 65mm * 16mm (but connectors on the sides)

For charging only (bypassed BMS) this would be an option but it’s not really smaller than the others above

size: 69mm * 57mm * 15mm


I made a 2mm ABS plate for cable management / strain relief at the rear truck.

The mess is from Loctite

Normally I route the motor wires on the hanger first but this is not possible, there is no space because the motor is too close.

Next is to drill holes for threaded inserts in the deck. Since 2 days I can’t decide where to drill because my actual “enclosure” is different than later. It’s tricky to plan enclosures for something you don’t know yet with different batterys and layout.

The concave of the deck is 8-9mm when you want to use the full width (21cm)

I am thinking about mounting a 14cmx22cm plate for now


I’m designing the same for routing and protecting my cables going over the back right now, but mine will be metal, with washers used for spacing between plate and deck, on top of using truck bolts to mount.

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My current temporary solution while I figure out final wire length.


Much better for sure, at least I use high grade plastic :laughing:

On the rear I prefer wire routing like this with zero stress for the cables if there is space like on my Trampa.


Almost exactly what I’m going for, except I have MT60 connectors next to the motor, and my wires are tucked in tighter because I used the solid copper from the the motor as far as it would reach.

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May i ask how much you weigh? i am making a ‘‘lightweight’’ board too and i have those trucks i want to put on it but i may consider what jumps i do with it after i read that haha


How much does the jumpinator weigh?


I’m 74kg (163lbs) and the Trampa board weight was 16kg (with 12s8Ah Lipo) but now it’s 18kg (12s6p).

Something like this won’t destroy trucks but it could be that the axles/ end of hangers slightly bend upward.

I’ve bent and twisted several trucks/hangers but usually it happens after an impact like hitting a snag, tree, rail, wall or whatever was in the way :man_shrugging:. I’ve also bent 8mm and 10mm motor axles.

In the beginning I was riding carefully but after some time I realized that it is more fun when you just don’t care even when that means spending more money for broken parts. For example sliding or burnouts are very bad for tires but very good for my mood :laughing:

I don’t know yet but approx. 12-12.5kg (26.5-27.5lb).

The original Jumpinator (Trampa) with belt drive was 11.6kg (25.6lbs), unfortunately I had only fun for about 50km (31 miles) but at least I recorded some footage.

In the first video it’s a 16ply Trampa Holypro deck and in the second a 14ply Carver deck. You can see how much they flex (bottom out) when landing. The 14ply was veeery comfy and smooth to land but less control. I think I’ll miss the flex on the MBS deck but I guess it’s easier to handle when landing because it doesn’t deform in all directions. But don’t know yet from where to take the energy for active jumping, very curious.

Talking about weight, I did a comparison of the MBS Vine and cheap Aliexpress clones last year, the weight difference is 0.6kg (1.3lbs) for 4 tires.

And for those who don’t know the 14ply Carver flex test here it is (with 7" wheels). This is the most stupid video ever :laughing:

Enough videos for today… aah let’s add some more I think I’ve posted them on the builders forum only

Thanks for watching :grin: