If you manage to setup a small group buy of the 7" ones, i may be interested lol. I’m realizing that if i want to run my deck at axle height, i need some pretty large wheels to clear the enclosure with any reasonable amount 
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Renders of Phase 4. Here’s what the whole board will look like (bindings will of course be added).
Here’s the stainless steel subframe. As far as assembly goes, it needs to be bent into shape, then 2x3 M8 bolts hold the truck mounting part together. The triangular part on the bottom will be welded shut. And of course gonna add a couple bolts to mount the deck, just forgot to model it.
With place in the bottom for a couple cells, so I’m probably going to be running a 20S5P in the end.
Here’s the thing unfolded.
And an auto generated quote to see how much it is to get it manufactured from 304 stainless… I really, really, really hope it’s going to work out for the first iteration 
In the ends I need one of these to hold the trucks in place, these will need to be CNC machined. Held into the frame by 4x M10 bolts.
Specs:
- 75 cm standing platform
- Wheelbase variable between 97.5-102 cm
- Integrated angle of 35 degree - will probably be running some dewedge in the rear, but probably perfect for the front
- Standing platform height variable between 45mm below axle and about 20mm above axle in the shortest wheelbase position. Longest wheelbase position maybe around 55mm below axle to 10mm above axle.
- Ground to standing platform can be as low 72-82mm depending on wheelbase on the absolutely huge 10" gokart wheels
- Rear motors basically touching each other with 240mm hangers
- No clearance issues for the full 33 degree articulation - but I might need to run longer wheelbase so that my feet doesn’t touch the tire when turning
- Total width of about 50cm from the outside of the rim to the outside of the other rim
- Total length including tires 123-128cm
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Just curious what top speed you will be shooting for with this build
It is only getting used on the race track. I don’t really race long track, only short and medium tracks.
Given the 22kW of peak power of the planned 20S5P tabless battery, I’d say maybe about 50mph - 80kph is what I am realistically going to be reaching assuming I’ll actually be putting down over 20kW. The open gears I acquire at esk8con will allow enough ratio so that I can gear down to this speed.
But I could also run a lower ratio for long track if I ever feel like it. It won’t feel underpowered if I keep my small wheel ratio which gears it for 75 mph - 120kph. Just puts more stress on the electronics.
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If you are keeping it under 50mph,
Have you considered onewheel hub motors instead of gear drive?
I realize mounting might be weird. But the torque would be unmatchable.
Plus they are almost silent, and no chance of gear issues
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I haven’t yet but I don’t think I have anything to gain.
Mounting is gonna be weird. Torque will already be enough at a 50 mph gearing to spin all four wheels simultaneously unless the tires will grip for an acceleration around 1.1G, at which point I would accelerate comparable to a 1300cc Hayabusa and close to 20% faster than the current fastest time recorded on an esk8
Silent is actually a con for racing. People aren’t aware of you on a silent board when you get close up to try and overtake. Safer if they hear you, less chance you’ll get cut off.
Regarding tires that fit gokart rims, I think all onewheel rims are about 6" wide? 4x that contact patch is impossible to heat up so that they grip properly with only about 120kg total weight. I’m thinking in the range of 3.60-4.50 width tires all around, preferably on the lower end of that spectrum.
And I also don’t want to be committed to running only gokart tires. Some surfaces fit certain tires better, and gokart tires is completely untested territory on an esk8 at our usual tracks. They should work pretty much everywhere in theory where gokarts work well if I can heat them up, but having the ability to fall back onto our usual tires like BRP and narrower indoor tires like exway venators and mboards novas is a good thing. Perhaps I won’t be able to get them up to temperature on an esk8 on some slicker surfaces.
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I’m running the untested BRPS from top level RC
Last night I pulled 2.23Gs I could barely stay on the board.
But also the rears may be lacking grip since they are “asphalt rated” I manage to fishtail & wipeout on a hairpin.
Rear: https://www.toplevelrc.com/products/brp-tires-405-street-slicks-in-stock-now-4-wide-standard-6-wheel
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Yeah he’s talking about that added foam on the larger 7" wheels. The host is only 100 ish mm in diameter, just under 20mm foam profile on the 6’s. Add the extra height in foam and they’ll likely be more compliant but get them hot and I would assume they’re gonna be quite squirmy on the corners. I can see it already from the way the pinions wear the insides of mine. Interested to hear how they go.
I think it was talked about above but hitting bumps can register spikes in peak g’s. 7.2 is my record looking at my data 
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I’ve actually been discouraged enough that I’m probably not trying them for the immediate future unless if Moe would decide to stock it before I buy 6", as he knows his stuff around BRPs much more… I don’t really want to run untested tires at esk8con that I buy direct, if they fall apart they could just end up ruining my race, to which getting out is a shit ton of money plus if I injure myself there’s no free healthcare out there, so I want to minimize the chances of that. That said I want to run BRP’s there so will probably end up on a 6" set from Moe.
I’ll be much more open to experimenting after esk8con, or if I don’t have to place a blind order that may or may not work out, but then the first priority will be the gokart wheels and chassis update, which I suspect will keep me busy for a while. Once that’s done and the 6" set wears out I’d want to buy some 7" though.
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It really takes away the board aesthetic, but I kind of love it. Looks legit.
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Made some refinements to the design and increased length as I realised I currently have more deck real-estate than what I remembered, so needed extra length.
Bad news, now it doesn’t auto-quote, meaning I probably went over some standard material size limit or something.
Deck is changed out for a 5mm/6mm aluminium sheet, thick enough so that it can countersunk M6 screws, while being flat so I can build up concave exactly how I want it.
Figured I don’t want to chop the Hellhound as it’s such a nice deck, but also don’t have anything on hand with the right dimensions so might as well get an aluminium one made. It’s actually not even that expensive.
Variable ride height adjustment range
Doubt I’ll use the lowest set of holes for anything other than taking some photos but we’ll see. In the lowest setting it would probably be the only board on the forum that has better clearance when ridden upside down 
It can fit 4x G300 and 20 cells in the belly pan. I’m definitely going to be utilizing those 20 cells. G300 fitment is just for future proofing since the chassis is about as future proof as it can get on current tech. Also there’s mounting holes to move the 2x D100S down here, not sure if I’m going to bother repositioning them but the option is there. I’d need to see if the extra height I’d gain by repositioning them can result in more cells in the enclosure or not. If it can it’s worth the effort.
Bellypan for protecting the electronics - not required for strength. Considering making this from ABS instead of steel for cost and weight saving. And I have a bunch of 3mm ABS anyways.
If no G300 is being used the belly pan can be as shallow as it is in the middle of the deck - that’s probably how I’m going to be making it if I end up doing ABS. If it’s made from steel some scrap material needs to be used to bridge the gaps that inherently come from the folded sheet design and then it’s adds strength as well.
Now the design is more or less final. Although won’t be ordering the chassis until I’m back from esk8con.
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Confirmed I can make 20S6P happen!
The way to do it is the following:
First a 14S6P brick, will require me to buy some 50mm wide copper.
Then a 2S6P flat pack on top, with the BMS next to it
This takes up about 100mm vertical space once accounted for insulation and everything, with 108mm to play with in total - so I should have about 8mm space for the hardware at the bottom of the enclosure - so I should be able to fit it, but I’ll definitely have to be mindful of pretty much every dimension during the pack build.
Then 2x 2S6P flat packs in the bottom, along with the 2x D100S:
Needless to say it won’t be an easy battery build, but it looks doable.
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Holy shit what a deal I just got. Tires will be here this week. Not like I can use them for the immediate future, but still.
40€ including shipping from a local company for a set of 4 brand new 10x4.5 Bridgestone YPB tires. 36A hardness.
Granted they are from 2020. But still in the plastic wrap original packaging and properly stored in a warehouse. Sure I might give up a bit of performance compared to if they were manufactured last year, but for 40€ brand new for the whole set it’s definitely worth a shot.
I’ll need to get some tire grease for installing them, they are tight fitting ones apparently. Well they better be with a 200 km/h speed rating.
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What wheels are you going to run these on?
These 5" rims with 115mm internal width, the BRP hubs I am getting, and a custom made adapter piece which I’ll need to get machined somewhere.
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Next up I’ll need to buy some tire grease, so that I can actually put them on the rims.
After that the next obstacle will be the hubs and adapters. If all goes well the hubs should be finished in 7075 for esk8con, not sure about the adapters yet - the budget is first spent on flight tickets and such… The kart tire project is not going to appear in Vegas unfortunately.
But! I’ll be 3D printing the hubs and adapters for test fitment soon, just to make sure that I get the tire offset perfect when the adapter will be made from alu. And also because I really want to see just how ridiculous it would look.
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Prototypes 3D printed, fitment is good! Some considerations: the hub adapter will sit about 2-3mm closer to inside if my printer wasn’t as shit at bridging over supports as it is, the gear would be just about level with the hub now. So I’ll probably move the relevant face by 2mm to have any actual clearance, as I can’t afford to move the gear further out, then the innermost bearing would stop taking it’s centering loads.
Valve access is shit - the rims need to come off the hub to be able to adjust pressure. And it needs to he released specifically at the BRP interface. It was designed like this in order to be able to have the rim as close to the inside as possible.
However, due to it needing release at the BRP interface specifically, I’d need two sets of adapters machined if I want to be able to swap to different kart tires on race day, as I’m not going to be taking tires on and off the rims all the time. So another set of rims and hub adapters will add to the cost. Still considering if I need two sets though. Would definitely be good if I end up cording a set mid race or get a puncture - and the rubber is super soft so it wouldn’t be hard to get a puncture. Plus of course this allows me to bring two slightly different compounds and I can do head to head comparisons between them… Within a few minutes.
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