So, how do I start. Over the last year or so, since I finished the first iteration of RaceBro, I’ve been taking racing fairly seriously, been constantly upgrading my setup, trying to make it out to as many events as I could, and practice a lot. I’ve improved my riding skills heaps along the way, with just recently making it to the pro finals at esk8con on the most recent iteration of RaceBoi:
This journey of racing and building is well documented in the thread RaceBoi, which has by now grown itself to over 600 posts. That thread has also shown my lack of self control skills for building esk8s - I’m always striving for what I consider at the time the best thing that I can possibly have. And this brings us to the name of the board: PROJECT: ENDGAME. Firstly, this is so far, just a project. That has been going on for some time now and will continue to unfold over the rest of this year. Secondly, endgame. I’m hoping that by getting ahead of where every other setup is now, I can finally make a setup, that I just can’t upgrade anymore, because there’s absolutely nothing that can be upgraded on it, everything is top notch, even by my ever-evolving standards.
Since about last December, I’ve been working on a new project that’s much larger in scope which I’m hoping brings real innovation to the esk8 racing scene. The main idea with this project, is to take all the tire development that the kart racing scene has received, and fit them on an esk8. But you can’t just fit 10x4.5" tires on any esk8 and expect it to feel good, there are many pitfalls during the way I came across while optimizing ride feel. You need a chassis designed from the ground up to make this happen in a way that’ll feel good on the track and be indestructible. Before we dive into it too deep, be aware, this WILL be a long read.
Trucks
First a little bit about trucks. I’ve tried all kinds of trucks over the years, and Dualities by @Titoxd1000 are the best ones that I’ve ridden on so far, hands down. They achieve a precise zero slop feel, they take any regular skate bushings (including WFB), they are easy to work on and can change bushing setups within minutes. So Dualities it is. But what width? Well, the kart wheels are so wide and so offset, that I want to minimize hanger width, so I went with 240mm for now. And tried to design all clearances around that.
Wheels
Now, lets talk about the wheels, as the whole project is centered around fitting them. Full size racing kart front wheels are most commonly 10x4.5-5, so that’s the target. It’s as small as the best kart wheels can get, unfortunately going any smaller would mean compromises in tire compound. Chronologically the exact tire choices were only decided later on, so for now lets talk about how to fit the rims.
The custom MBS pattern BRP hub development from @Ac53n has given me a good start with a wheel hub - the original plan was a chassis that can swap between BRPs and kart wheels in a fairly short amount of time, so I went for these. If you stack these fully with bearings, you end up with an insanely wide bearing spacing, and they are adaptable to many setups. More about my exact bearing setup a little later, but for now the important part is that the sheer size of these wheels require me to run a very wide bearing spacing, which these do support. Afterall, they were designed to run on 17-20mm shafts, not 12mm.
At around the same time these were being designed, I found a set of kart rims which have a fairly rare 55mm centering bore, instead of the much more common 40mm centering bore of 5" rims. This is important, because this is what we needed to be able to have the BRP pattern and the kart rim pattern on one part. Meet the Righetti Ridolfi KC70AL125-67. 5" wide, 5" diameter, 55mm centering, 3x67mm M8 bolt pattern.
So, these obviously don’t just bolt together, what’s up with that? Tommy designed up an adapter for me, which gives the rims the least amount of offset possible, so they stay supported as much as possible, while still having a little bit of the bearing left for the wheel spur. Huge thanks again! I’ve got two sets of these machined, hoping to be able to swap between different tires (for example practice and race tires) within a reasonable timeframe. Or for example if I get a flat mid race I don’t want to swap tires on rims between heats, I can swap them with the BRP pattern screws.
In the middle, this can also take bearings for extra support.
So a bit about that bearing spacing now. From hanger to axle nut, this is the plan:
hanger - 1mm speedring - 28x12x12 wide double row angular bearing 3001 - 6001 regular bearing - 22.2mm spacer - 6001 regular bearing - 6001 regular bearing - axle nut. There’s 1mm extra left after the nut for perfect nylock engagement, and the Tito Dualities 68.5mm axle length is pretty much fully stacked with 58mm total bearing spacing.
Another idea that I had just recently, but might require 270 hangers, is to mill a 30mm or 35mm bearing mounting interface for the 22^2 R6 motor mount part which would take an oversized gear bearing, and shift the wheel to the insides a bit, freeing up axle length on the outside of the wheel which could be used for extra bearings for an even wider total bearing spacing (including the spur’s bearing).
Everything was test printed when the tire arrived, and it went all together, signaling that these parts are ready to be ordered from metal.
Tires
Well, I have to talk about these too, even though I am yet to ride them at the creation of the original post. The main goal of this project was running top notch tires. For now I’ve got two sets of discontinued Bridgestone YPB softs to go through, as I’ve got an 83% off deal on them. These are close to what I’ve wanted to run anyways, but not the final tire choice. Given that my board is not as heavy as a gokart, and that esk8 racing is harder on my body than karting, I decided to go for super soft compounds, as I probably wouldn’t be able to overheat them anyways. The tire that I really want to try later on are Lecont LPM, they are the grippiest tire in karting right now, and they have stiff sidewalls, which I think is what we want in an esk8. Oh and I think this is the perfect place to throw in a size comparison to more normal tires:
Linnpowers (6.5") CST C190 slicks (9x3.5"), kart setup (10x4.5")
These kind of super soft compound tires are specifically made for the higher power karts, this one is for the 50hp KZ category, as they are known to bog down rental engines too much in the turns. Another reason for an electronics upgrade.
Also rest assured there will be custom gear drives in this project, but now lets get to the chassis itself, now that we know the constraints that I’m designing around - the wheels and the trucks.
The chassis - design iteration 1
Well, a raceboard has to be stiff and rigid so that the inputs by the rider are translated directly to steering.
Future me circa mid 2025: It was discovered that while torsional rigidity is needed, longitudinal flex is actually desired. More on that later. For now continue with the original post.
Rigidity calls for an all metal chassis. Also I’m not super experienced with welding, but I can weld somewhat. This made me want to avoid the V5 style tubular steel chassis. Let’s come up with something new, what are cars made of? Sheet metal. Let’s see if I can make that work. I can design for the parts to be able to take most of the load without welds already, and then the welds just make sure everything stays in place and add strength - they aren’t as critical in my design as in a V5 or something like that.
The design work for this chassis started months ago already. I set out a couple goals in the beginning: adjustable ride height, by a large range, being able to go down as close to the ground that I can scrape. (Mostly) top mount, with space in the frame for a few components - ESCs, and a small part of the battery. Standing platform length that suits my stance. Then as time went on, I also added the goal of an adjustable standing platform length, which can be used to shorten the total wheelbase by a fairly large amount. This last goal might be scrapped if it turns out not to be strong enough in FEA (finite element analysis). Early stages looked something like this:
Then I realized how I can make those ugly square towers look better:
Then recently I decided to get rid of that ugly pelican while also making the standing platform adjustable length, and making the bellypan capable of taking the makerx G300 ESCs:
Future me: I built a super half assed prototype with the geometries of interest, and I realized this isn’t actually the way. These plans were scrapped and new plans were constructed, but for now lets just continue with the original post.
Electronics
It will start running on my RaceBoi electronics in the beginning, so 2x D100S, 21S4P P42A, 2x 6385, 2x 6395 reachers. Then, I’ve got a cruiser board planned which would need one of the D100S, and then 2x G300s would go in. Roughly at this time, I’d also build a 20S6P battery for this board, 15S6P on top in the middle, 5S6P under. Tabless cells of course. After that the remaining D100S would also be swapped to 2x G300 as funds allow.
Future me: the battery ideas were revised, ESC refresh will be 2x 2G300.
Then, it will be time for new motors. But while I still run the reachers, let’s discuss the gear drive I designed up for the reachers.
Gear drives for reachers
Well, there were a couple design requirements. First of all, I wanted to be able to make everything cheap on a laser, the wheel spur was cut on a laser too. Secondly, ratio should be able to gear me down to 80 km/h or 50 mph. Thirdly, somewhat enclosed.
I ended up getting a set of clamps from Tito, designing my mounts around those clamps, which is just a lasercut aluminium plate, then designing a 3D printed cover and a spacer that mounts to the side of the gear. The gear itself is lasercut chromoly 4130 from sendcutsend, not as nice as hobbed gears, but it does the job and it’s cheaper. They do appear to have a different sounds profile and maybe even a bit louder compared to the stooge open gears.
There was another design requirement, and that’s quite a strange one: the kart rim needs to run inverted for the proper offset, which makes the valve stem face towards the inside, which is rather inconvenient. I designed the gears and the mounts so that I have plenty of space to pass a valve extender through the whole assembly, so that I can inflate my tires without having to disassemble the board.
Back to electronics - motor upgrade
So, all the cool guys are moving to inrunners nowadays. I’ve got a couple challenges - I don’t want to move below 20S, so 600ish KV is out of the question. And I also absolutely hate the look of staggered motors like the new stooge setups.
I’ve found these long boi SSS motors, that are nearly as long as the distance between my mounts, so I can print like 20mm spacer or whatever and then it looks like two full length cylinders.
At 330KV this motor is rated for 75V, so what could go wrong if I do 20S. I intend to only charge to maybe 4.0V or so per cell, so that hundreds of amps of regen won’t cause that much damage to the battery. So close enough to that voltage rating, and not like I’ll ever be riding top speed anyways. Rated for 14kW constant 20kW peak per motor I’ll be able to gear to top speeds I can never reach and still have infinite torque. Probably doing a ratio of 12:1 or somewhere in the neighbourhood of that, requiring the design of a new gear drive, more on that when I actually get to it. Rated for 266A (continuous (I think)). Hoping to be able to set 400-500 phase amps on G300s and never reach it due to not having enough grip with a 60 mph gearing. Hoping to have enough torque to not need to run any power to the front for maxing out total traction, and not need to run any brake to the rear. That would mean complete freedom for tweaking my bias, without having to worry about any power compromise. And hoping to set 400+ battery amps at 20S, and never reach it because I’m not that crazy (yet).
Conclusion of original post
PS: I’ve decided to break this out from the RaceBoi thread, where it doesn’t really fit that well anymore, so it’s not burried under 600 ish posts. I’ll first try to fit the kart wheels on the old chassis just because I’m impatient and can’t wait for the frame to be made, but progress regarding the new chassis will all be here in this thread.
Timeframe at time of original post: Running the wheels in May on the current chassis. Hoping to order the new chassis soon after, probably after having done the first ride on the wheels. Hoping to build out the first iteration on the new chassis by mid July. First pair of G300s ideally during the summer, second pair and new battery probably autumn, new gears and motors late autumn/ winter.
From this point on, it’s update time
There have been many unforeseen changes since the original plan, and these pushed the timeline back for many things. Developing stuff and pushing the technology forward ain’t easy!
“V0” iteration - throw em on Raceboi - post 12 onward
As soon as I had every wheel component from alu, I basically just setup the wheels on Raceboi on the esk8con drivetrain to see what needs to change and get a quick first impression on the tires asap, I was very excited.
I was impressed by the grip and directness, but wheelbite prevented me from pushing the tires hard, so that needed to be fixed for sure. Funnily enough the wheelbite didn’t happen on the deck, it happened on my front toe on the shoes and on the rear heelstrap. There goes my ability to simulate wheelbite in advance! And I also learnt that the original CAD design wasn’t actually long enough to avoid the footbite issue fully.
“V1” iteration(s) post 22 onward
At this point I wanted to do two things, drop ride height and eliminate wheelbite. Dropping ride height eliminates wheelbite I got started on that.
First some mockups:
I didn’t actually get to ride these. I tested the flex and it was a very unhealthy amount for the deck, and I would’ve definitely scraped the sides in corners if I were to actually ride this. I also noticed a lot progressiveness coming from the trucks at this ride height, but more on that later once we actually figure things out. But at least wheelbite was solved.
Next I took some square tubing and I welded a frame that (more or less) perfectly fits to the bottom of the Hellhound and the extenders I cut out from a piece of aluminium plate. At this point I increased ride height a bit from the above shown pictures such that the standing platform is 30mm below axle. Little less progressiveness.
Yes, right outside the house in the grass is the perfect place to weld…
Put the board together like this and rode this “chassis” setup for a few practice sessions and took it a race in Pitland. This essentially emulates something like a middle ride height on the CAD modeled steel chassis - the most important rule of prototyping is to test things as soon as possible, often in their most basic form, so that not too much work is wasted on stuff that’s doomed to fail.
At this point I was really feeling the awesomeness of the tires, but the handling felt a little alien. I tried tweaking it in the usual ways → compensate with more angle for lost flex and extra wheelbase, and compensate with bushings as well. I tried even my softest bushings on hand and I just couldn’t get the feel right, it was hard to get it to turn tight - in huge part because of the progressiveness that I introduced by going below axle and reducing leverage over the bushings. Ordered some bushings to Prague to play with at the race, and decided that I’ll stick with the setup for the race, even though I was considering converting back to the supernovas to pause the experiments until I’m back.
Couple more things pre-Prague
I changed from 22T (the supernova setup) to 12T, to have a gearing better suited for the huge diameter increase in the tires.
Welp.
I had to end the first session on them early because I wore through them quicker than I could deplete my battery. And by wore through them I mean I completely lost tooth engagement. I also barely seen an increase in torque, and this was sort of verified with data. The solution is to grease (or in the case of open gears, more like oil) your gears! After lubing them up the power was only slightly less than expected, instead of like 60% of expected… Good. Took a bit of time to figure out. At the race Tilo came in clutch and brought me a set of 12T gds pinions, which are still holding on in early 2026.
I also blew a D100s right after hooking up sensors, 2 days before leaving to Prague… On the 4WD setup that has the most tire to road surface/ contact area out of all… Sort of confirming Radium is right regarding the static issues being a thing? Tilo came in clutch for this as well and brought his 2 old D100s ESCs to Prague.
Pitland updates (2025 May) - post 88 onwards
Had some small success and some big failures. It started out very rough, first trackday went by changing a blown D100s… to one that happened to poop itself when I plugged it in (I did manage to fix it months after)… Then over the next day I managed to swap in one more which finally worked, along with swapping to the GDS pinions. Finished the board at 3am on the day of the race, put in the brand new bushings with a weird setup, then went to sleep. 93/95 cone front 95/95 fatcone rear…
The floppiest front ever while still turning that well, and offering way more resistance in ride feel then it should
So how did the race go.
Well I could definitely get around the track with the board, but the sacrifices made to be able to turn were too high.
I set the at the time fastest lap in qualifying, then wobbled out and got broke a moto helmet… Yikes. Also it was by far the most aggressive wobble I had. On my “normal” duality setups (like raceboi and racebro) a wobble would normally manifest itself is a very gradual thing and I was even comfortable slightly tapping into wobble territory often. This however just came from nothing and took me down without me even having a chance to resist.
Yikes. I had zero symptoms the day after so nothing actually serious thankfully. But regarding the setup, I went back to the drawing board. Issues being progressiveness caused by standing below axle, slightly too long wheelbase, lack of longitudinal flex requiring increased truck angles, way too soft bushings needed to be able to turn, very intense wobble behaviour.
“V2” - “the temporary solution” - post 103 onwards
After a few weeks of break that happened to perfectly line up with my exam period anyways, I setup the board again.
What I did is that I basically took of the welded tubular chassis to regain flex, kept the extenders but shortened the setup as much as I could while still not having wheelbite (-6.5cm wheelbase), also added risers as needed to bring axle back inline with standing platform, lowered truck angles, put in my esk8con bushing setup (93/95 barrel front, 95 fatcone / 100 chubby rear).
This setup as is, is awesome. Everything feels in synergy with each other. Minor issues being that I have a bit more flex then I think would be healthy for a wooden deck longterm, and that I the more longitudinal flex I have the more torsional flex I have also, and torsional flex is bad. While it’s not too bad on this setup, it is noticeable with double bindings, which is exclusively how I race. Plus of course the electronics still need upgrading.
Race performances on V2 and minor changes
T-race
As of January 2026, “V2” still holds the first place in T-race, at 12.43/12.51, which are seriously quick times.
Pardubice 2025
I achieved 2nd place on this setup in June in Pardubice, mostly struggling with electronics issues, namely battery heat (80c+ in the poor 21s4p p42a pack, even had to skip a heat)
Budapest race 2025
For this race I set up a set of lipos which performed great in the summer. On this track, BRPs just didn’t even have a chance compared to my underinflated kart tires.
It ended up being my first win!
Brno race 2025
During the practice at home for the race I ended up breaking a kingpin, realizing my bushings are toast, and changing bushings.
Went for one more practice on the new setup, and I wasn’t sure if I like it. The rebound was so low I can’t even describe it. Turning became insanely easy and turning radius is basically non existent. Tapered barrels front, fatcones rear, all WFB.
So I managed to forget my bushing box when leaving for the race… Great. Then I was really struggling during the freeride before the race, due to battery heat… But it’s the other way you’d think. If you have cold batteries, they have higher internal resistance. While the lipos were cold, I barely had any power, which is basically most of the freeride. So that didn’t set me up for an optimistic mood for the day. I had significantly lower top speed on the cold battery and at the time I had no idea why.
Just barely, but still managed to score 2nd place.
Pitland season finals 2025
I finished this race at 3rd place, despite messing up bigtime by forgetting my brand new set of wet kart tires at home… I ended up getting a set of trashed wets from Kartplanet for free and I raced on those.
Swingarm setup planning - post 182 onwards
I’ve started from the ground up around September to CAD up a new chassis, that has perfect torsional rigidity, and has swingarms that are inspired by Radium’s solution, however have been designed from the ground up with modified geometry and the main goal of reducing turning circle when loaded.
As of January 2026, I’m working on building this chassis out ASAP. I have acquired an old CNC mill, which I’m rebuilding with new electronics (and eventually upgrading some of the mechanical parts as well), which is crucial in order to be able prototype, and eventually even build stuff for sale.
Swingarms
This swingarm based suspension would be a great way to emulate the good parts of a flexy deck, and have the effect be adjustable.
For the kart wheels specifically, they have a synergy with setups where tip angle flex increases truck angle. On a stiff setup with regular esk8 tires, slip angle can be used to fine tune your line mid corner by changing the pressure you apply. This is done by slip angle reducing your wheels effective turning angle - making turns harder. The kart wheels, especially the slicks, feel so direct that this control is lost with a stiff deck, hence they require a flexy setup for optimal ride feel and control. The swingarm (and flexy decks) increases the turning when more pressure is applied, giving back the ability to fine tune your line mid corner.
Furthermore, better turning with a loaded suspension means that I can generally run lower truck angles, gaining stability, without sacrificing any turning.
I’m expecting to have my CNC up and running by end of month (jan), at which point my main focus will be to actually make all the parts required for the new chassis. When the board will be assembled in the new chassis, a 2G300 will be used in the rear (and a spare D100s in the front), along with possibly going 20S 2P lipo. Eventually a 20S5P tabless pack will be powering the board.
Double stage drives
I’ve designed these double stage mod2 gear drives around the SSS56154 motors. I plan to make these, eventually. But first the chassis. Then I want to experiment with 8M belts. Then these drives. So it’s a bit further down the pipeline.
I’ll be watching closely
and wanted to throw my experience out there. Best of luck with the build!
