Yeah, the deck is also a lot higher off the ground than normal boards, way more clearance.
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Good session today with a few shortish rides over an hour or so, until the batteries were mostly discharged. I went around paths, packed dirt, clumpy and long grass, and over concrete/gutters etc. got it up to around 30kph I think, though that was when a helmet didn’t feel like enough safety gear.
But man, what a rush. Some of the most enjoyable parts were riding over really bumpy terrain at speed, or transitioning between quite different terrain types, trying to hang on.
Anyway, the board is just fantastic. No major issues. The mounts were a little loose by the end, pretty much just due to the bolts that go into the trucks through the brackets. There is no nut there and not enough thread in the truck, loctite isn’t enough. So I plan to drill right through the other side of the truck and use longer bolts with nylock nuts on the other side. Should sort it.
I also got some dropping of connection for fractions of a second on the Winning remote. It only occurred in one location, where I was near to a road with lots of fast flowing traffic. Disconcerting when it happens.
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Awesome! Glad it’s all working out for you. I’m guessing you have a lot of off road terrain in NZ, right? I’d love to see some more pics and videos of where you live and ride. I imagine it’s beautiful there. I hope to visit NZ one day. Everything I’ve seen looks amazing.
And not to second guess your plan, but you’re not going to drill all the way through the hanger and axle, right? I’d hate too see you end up with a broken axle or worse.
@dinodave this is an awesome build thread thanks for sharing it all!
However, unprotected lipos are anything but robust, and heat shrink is definitely not suffient to protect your vescs in the long-term. You might be alright for a few rides, but this seems like a major gamble.
NZ sure is a great place to live. Looking forward to having some videos to show off, but at the moment I’m still not quite feeling good about trying to hold a selfie stick while riding… Shouldn’t be too long!
These trucks seem to be hollow, so I will definitely be weakening them, but hopefully not too much. Definitely concerns me a little too though, but I really don’t want to weld or epoxy, as I’ll probably modify the mounts at some point.
I sort of figure if MBS are happy drilling one 8mm hole in these trucks, another one might be OK… Hopefully![quote=“treenutter, post:44, topic:7419”] However, unprotected lipos are anything but robust, and heat shrink is definitely not suffient to protect your vescs in the long-term. You might be alright for a few rides, but this seems like a major gamble. [/quote]
Those Lipos are so high off the ground, I just don’t think it’s an actual issue, unless I start doing jumps or rail slides. I’ll keep an eye on the ESCs for any dust issues, but this is the way I roll. Don’t fix it until it breaks!
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Ha, so I went for another ride today, this time in quite a different setting: a small-scale dirt BMX track.
My original goal was to build a board I could cruise along flat paths with, and this board fullfills that goal pretty well, but wow, there is a whole new level of fun this board could reach with a few tweaks! So sorry if you thought that was the end of my monologue, I have some modifications to make 
On the lipo/esc protection front, I now agree that a case is going to be necessary for true off-roading on really bumpy terrain. I started to fear for the safety of the electronics when riding over steep crests/ridges. I’m still going to put that off for now though.
But my main problem right now is that the mounts move too much. I got slipping on a belt today because the mount moved enough that the belt got too loose. That’s just not good enough.
I think the off-centre wheel pulley centre holes are the trigger. They cause an oscillation that tightens and loosens the pressure on the belt every motor turn. This tightening action puts pressure on the mount and bends the motor outwards towards the belt/wheel. It then loosens again and at certain speeds the oscillations get in some sort of resonance and the whole mount wobbles back and forth, I estimate by about 10-20mm at the motor end.
This gets worse as the ride goes on, because all this movement loosens the bolt holding the mount to the truck, and yeah. OK for about 15 minutes, then it needs sorting out with a spanner or I’m getting belt skipping and poorer performance.
So the first fix will be the aluminium motor pulleys I have on order that already have an 8mm bore, and will hopefully sort out those oscillations. The next fix I think will be thicker aluminium on the mounts, and an improved mount design I’m yet to fully devise. Shorter belts resulting in shorter mounts, but with a belt tensioner to keep enough motor pulley teeth engaged is also an option.
On a positive note, I also rode a couple of km along a river bank and back today, just carving back and forth at a moderate speed, wind in my face… This is the shit.
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Another <10s video, my mate giving it a go. I promise to get some better video one day soon!
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My new aluminium motor pulleys showed up today, and they are fantastic! I ended up with these XL 16t pulleys from SDP, as B&B manufacturing messed me around too much with shipping.
The new pulleys are absolutely perfect. 8mm bore and two grub screws that fit right into the Orlin motor keyway so I can just slide em on and tighten for a perfect fit.
With that, all my wobble issues are gone!
But I thought I would also get rid of the effect where the belts twist the mounts outwards at the motors by about 5mm, and went ahead with @baxter’s suggestion (thanks!), with two M8 sized threaded rods to connect them. It was a bit of a trick getting all the nuts tightened, but that will help keep everything tighter.
I took it for a quick test ride, and these two changes have made a massive difference. In high torque situations it’s finding traction a lot easier without that motor pulley wobble. And at higher speeds it’s quieter and more stable. I went full throttle up a steep hill at low speed, and heavy braking down hill, and there was no belt skipping.
I also found out that the reason I was getting belt skipping last time was mostly caused by one of the motors going offline. My canbus connection had come loose. I’ve now soldered wires to the pins directly, those JST connectors weren’t good enough.
This is my crazy method for getting those plastic pulleys off… at least that is behind me now.
Lesson learned: get aluminium motor pulleys, and unless you have some serious precision drilling equipment/skill, get them with the correct bore size pre-drilled.
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Another short video, this time from selfie stick.
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Haha bro your motor mount kills me, it’s SOO far away from the board! Does that thing wobble??
it did, until I got perfectly centered motor pulleys and rods to connect them.
The purpose of the long mounts/belts is to engage more teeth on these XL belts. Seems to work as I don’t get any slipping 
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Hey, whatever works right? Looks nice, but it seems like it could have been unstable, but I see the rods on either side, good feature 
When I had a long belt all I had were problems, I like my smaller mounts.
Out of interest, what problems? I guess it might be more likely for stuff to get stuck in there?
The mount was wobbleing.
I guess you should have tried making sure your pulleys were well centered and maybe adding some rods 
This setup should keep me going for some time, but in all honesty, I do agree, I don’t really like how far out they are, it looks a bit shit and won’t be as stable when I get more confidence and start going for airs and stuff. Am looking into wider belts/HTD pulleys so I can get a more stable/compact setup.
Well it was a single drive setup.
I was rocking with unprotected lipos on one of my builds for years before it got hit by a car…
they were more robust than I thought.
I recommend covering everything up. 
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@lowGuido No lie man, I actually thought of this build of yours when I was originally typing that statement! Also, I like seeing that I’m not the only one here still using Dean’s Ultra connectors
Since @dinodave is riding off road, a flying rock, stick, or any other piece of debris could puncture the casing. We all know what happens next! LiPos are great and seemingly very sturdy until something hits them or they are damaged. I fear for anyone who has a punctured LiPo and doesn’t know it!
I’m just going from the dozens of quadcopter crashes I’ve had with these LiPos, unprotected on-board. Direct hits at high speed into rocks/trees/everything, and my carbon fiber frames got dinged up or an arm broken, propellors disintegrated, screws snapped, motor shafts bent, but never a battery explosion. I did bang one up enough that I decided to discharge it and dispose of it, but seriously, they need a sharp thing delivered with force. I don’t think even a loose nail flying at 50km/h is a threat.
On the extremely unlikely chance I do hit something very sharp that is sticking out of the ground more than 5 inches at just the right angle and it manages to puncture a battery, I’ll jump off when I see the flames and enjoy the show
Something that is a serious threat which I think hasn’t been talked about enough in this community is explosions while charging. That I’m very careful about, always double checking cell voltages and balance charging every time. If you over-charge a cell you’re going to have a bad time.
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