I am super excited to share my latest creation with you all. Still in progress but I expect to finish it this week. The build thread will be a rolling build thread. I will put all the progress into the replies and update the first post once the build is finished.
The reason this board exists, is because I want a jack of all trades board so to speak. Something that performs while racing. Something that performs out in the woods. Something that has way too much power. Something that looks kinda decent. I wanted to stay on the mountainboard platform, as I am very comfortable with Matrix IIs on riptide bushings. I do wish for more power and speed than my previous mountainboard, so I am selling most of those parts to a friend and I am building a new board basically.
Specs:
My trusty 2021 stiff Haero Bro deck. It’s my favourite deck by a long shot.
Keeping the F5 bindings and heels from the previous board too.
BN310 channel trucks with an M1-AT straight cut 5.2 gear drive
MBS Rockstar Pro II XL rims - with a 3D printed widening spacer
9x3.5 slick gokart tyres for the ultimate asphalt grip and a set of 9x3.5 turf tyres for offroad grip
21S4P P42A pack built by myself
The most overkill fast charger that you can imagine - adjustable voltage and current up to 92.4V 34A
MakerX D100S with a small external heatsink, pointing down towards the bottom of the enclosure
Placed inside a pelican storm im2050
Reacher 6395 v6 175KV motors @180A hopefully
GT2E remote because I wanted to try trigger and because fuck Flispky and their VX1s that tried to kill me
Some clever cable management ideas stolen from @Shadowfax’s 4wd lacroix, more on that later
I went a little overboard with the speed to be honest, as I am mostly racing short track. Don’t think I will push it past 40mph but we will see. Got a bit carried away by the HV trend. 16k RPM at no load 4.2V per cell. Once I have my CNC up and running I’m probably going to machine a set of (straight cut, steel) gear drives somewhere around 1:7-1:8. 1.5kN would be sweeeeeet. That won’t happen until the summer though, probably. And 1kN is still very nice until then.
This is also the fastest build that I’ve done so far. Started shopping mid January, will have the last parts in by tomorrow. I started building last Friday, and I expect to finish the board this week. Hopefully by Thursday.
Meet the CST C190 9x3.50-4, right next to a standard clever 200x50. Now that’s a difference. This also meant, that widening the rims was not just a plus, but a requirement even.
So I designed widening spacers for my MBS rockstar pro ii xl’s, that I printed out. These use the locking feature of the hub, with a decently tight press fit fit, which should help keeping the tyre run true. I would like to get them machined out on a CNC mill one day out of alu.
Both of them grip really well, and both are really heavy. Sadly it makes jumping significantly more effort, especially as I am still recovering from a sprained ankle.
Thank you! I am super excited to have it finally come together! I took some inspiration with the cable management for the phase wires from your lacroix I can’t wait to share that too
On paper yes, but it actually measures around 210mm inflated without any weight on it. With weight I think it should be closer to 205mm
I hope I can do 180A. The 95s are super beefy and the 175KV is also pretty high. Should handle similar amps to the 205KV 85s. The D100S should be also fine when exposed to some air hopefully. I would love to gear down more but I am already at 5.2 and I need a closed gear drive. I’ll make it happen one day. I need a 1:8 ratio though. I expect to have a CNC up and running around the summer, I will mill a gear drive out on that.
I’ve already bought a GT2E for the build that I am probably going to print a smaller case for. So far I like it but we will see. It’s a good option that’s for sure
I’m stoked to see what you’re doing, and I gotta give credit to @poastoast - the ESC under battery strategy (and phase wires footpad) was all his idea.
180a puts that motor at 9.8nM max torque, which seems very plausible for a 6396 motor. (even tho it’s above reacher’s max torque spec of 6.5nM.) I believe that reacher way under spec the torque for whatever reason, but it is rated to 10kw for power at 75v
Regarding the cable management I am also going to have the D100S below the battery, and it’s going to be heatsinked. I printed a channel out of TPU to go under my feet (and avoid the bindings). I’m going to stack the rest of the area with some foam to leave a tiny bit of W and put some griptape over.
Then I also printed out a piece that goes over the antisinks, and uses the spring adjusting holes on the deck to mount. Here the cable will get passed under the deck and to the motors.
Here you can see the two prints in action. I still need to wire up the box and assemble the gear drive, before making the actual wiring, but this gives an idea about how it will look.
I’ll probably reprint the cover over the trucks once I get some black filament, I don’t really like the color, but this is my last roll of filament that I am actually able to print decently
More pictures on this once I have the box finished and the mechanics assembled, so that I can decide on the final wire length
Thanks! The tyres are great These are the same ones that @Swol_Moon uses. I’ll get to T-race them properly soon and try to find their limit. So far I had a 10 minute session and did 15.43s as a starting point on my old board, while being low on charge and hitting top speed. I definitely need to learn to lean in more with these than with the 200x50s.
Very well said! I am excited to put them to the test.
I personally think I like the 8x3’s better unless you’re pushing to the absolute limits. The 9x3.5’s have a super stiff sidewall that you start to notice after a bit on an imperfect track.
Interesting. On the track the stiff sidewall is a pro I think. They feel super predictable, and they don’t really flex sideways like the 200x50s that I had before. But I only had 10 minutes of time riding them, and it was all on a smooth and grippy parking lot.
Actually I haven’t widened the bearing spacing at all. It’s still on the standard MBS bearing spacing, and even fits on matrix IIs!
You can see it on this picture that this hub has both bearings on the inner piece, this is why it’s possible to widen it but keep the spacing. Just needs longer screws and that’s it.
I can’t wait to share that too
