I was just a tad overzealous with the bolt preload.
What an expedition! That track looks fun, but almost entirely hairpins 
Maybe the terminals need a wrench flat on them? The solder shouldnât be experiencing torque in the first place.
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G300 Repair V2
Talking with @YUTW123, he wanted a close up video of the problem with G300.
You can see the broken PCB
In an attempt to understand the construction and apply a more permanent fix, I removed as much solder as I could from the bottom of the PCB.
TIL the terminals are held in place with a Philips head bolt.
The bolt was soldered into the hole, and I couldnât get it to spin freely to tighten the terminal. The terminal was freely rotating though, so I tightened it onto the soldered bolt
I took a close look at the PCB. Thereâs an area around the terminal thatâs a copper pour filled with vias, whose job it is to transfer the power from one side of the PCB to the other. (roughly outlined in red)
The top layer had broken off, but it exposed some internal layers. However, these part of the internal layers are there just to transfer power to the terminal.
With plenty flux, I removed the broken part of the pcb stuck to the bottom of the solder blob and soldered directly to these internal layers.
Pretty? not really. It works though! Just in time for Legend League
Legend League
Apex Racing Center, June 7th.
Crazy long track with incredibly long straights.
The day was hot, and the track abrasive.
After a single outlap, my tires were already up at 60~70 degC
I got a great start in the final. Staying in 2nd place, keeping pace behind Jack.
Then I suddenly got bumped by Redbeard, getting tossed off my board. First time my board has ever flipped
I was at the back of the grid by the time I was moving again.
On the bright side, it was fun moving up through the grid 
At the end of the final, my tires were at 80C+. Not a system malfunction, I confirmed with a commercial IR gun
Insane. No idea how they didnât blow up.
Repairs
In the crash, my board sustained surprisingly large amount of damage. The highlights are;
- Megan rubber destroyed, case scratched.
- Rear tail bent/scratched
- Racebox micro broke off (never seen again)
- Insta360 broke off (somehow didnât scratch the lens!)
- Front box bent
- Broken temp sensors
Still ridable, but not ideal⌠Iâve got a lot of work to do!
T-3 days until Electrify LA.
Also, itâs new PCB day! Stretch goal to also install these in time for the race.
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Collision at 1:20
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Iâm such a Tucker fan.
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Updates
Been Awhile! Been taking it easy the past few months, but lots still happened.
what legend leauge did to my tires
New Temperature sensors
Previously, my temperature sensor mounts were designed to work with a COTS breakout board. Mounting holes on one side, and theyâre partially covered by the lens on the low-FOV variant that I use.
Predictably, these old sensors kept breaking (Thatâs usually why one or more sensors arenât working in pictures from previous posts)
So I designed a new PCB to fix those issues.
Three mounting points, larger area, and a less flimsy mount.
I wouldnât dare doing this with the old ones. perfection.
Temperature sensor fix
With new temperature PCBs, I was having intermittent communication problems. Quick investigation later, the pullup resistors I used werenât strong enough for the (relatively) high capacitance bus.
Little soldering later, much better.
What a loaf
Electrify Expo LA
The track was interesting, with the finish on a hairpin corner.
I had some fascinating temperature distribution
Tons of BRPs were destroyed that day, wasnât even particularly hot. Just a super abrasive surface.
I personally destroyed 2. @zero_ads came to my rescue, selling me two spare tires that he bought.
Was a great event, hope itâs not the last one!
Tire Testing
AKA a huge text wall
At the end of EE LA, @MoeStooge surprised me with a bunch of experimental wide tires to test!
4x 7" 45a (~830g each)
2x 6.5" 41a (~710g each)
2x 6.25" 45a (~730g each)
(stock 6" 45a is ~510g each)
Iâve tried a bunch of different variations. Temperatures were from a single night at the LA garage, which is about the most aggressive surface possible. Weather was typical socal (70F-ish). CCW track, on the shorter side. Iâd go until the temperatures stabilized and my legs gave out. Doing multiple stints (from cold) yielded roughly the same temperatures for every combination.
6" 45a Front and Rear
What I normally race. For a baseline
7" 45a Front and Rear
Predictably much cooler temperatures (larger tire, more rubber). I tried really really hard to get these up to temperature, but this was the best I could do.
Handling on this one was interesting, more on it later.
6.25" 45a rear, 7"45a front
Hotter all around?
Had a ton of trouble handling corner exits with this setup. I kept loosing the rear, fell twice. Probably because of the torque difference between the front and rear.
6.5" 41a rear, 7"45a front
Scorching!
This setup felt amazing. Super controllable and smooth, lots of rear grip.
I could really send it around corners, until the fronts started overheating and started sliding more then turning.
Conclusions
I am pleasantly surprised by the 41a compound. Itâs super responsive to start sliding with, had truckloads of grip, and didnât immediately dissolve. They were more forgiving at low temperatures, and heated up super quick.
The larger 7" tires are very⌠interesting. They have this loosy-goosy feeling to them, and they really werenât happy when they slide. I think this is primarily because of the very large sidewall (the same hub size as a 6" tire).
When they got above 45~50C, they really liked to start sliding.
However, through this badness, I could see greatness. Unsurprisingly, larger tires gave a substantial ride improvement. Felt more like gliding over the ground, rather then through it. This reduced the ânoiseâ going into my feet, allowing my to focus more on managing grip and my racing line.
I didnât really feel any loss in âsnappinessâ handling from the increased weight (510g->830g!) (if I did, it was offset by the improved ride quality).
What @Dinnye and @Steuka are doing with their raceboards shows that big tires might be the next direction esk8 racing will go (big tires definitely arenât inherently bad!).
I think a 7" (or even 7.5"!) BRP tire has a lot of potential.
To prevent the floaty, loosy-goosy feeling, Iâd increase the hub size from ~4" to ~5 or maybe even 5.5". This would increase the ârailroadâ feeling (by reducing the amount of flexible foam) and a nice secondary benefit of reducing the weight.
With the 7" 45a compound, I definitely wouldnât have been able to get them up to temperature without the help of the garageâs aggressive sandpaper surface. I think 41a would be better then 45a for a larger tire. It would be easier to get such a larger tire up to temp because of 41aâs higher low-temp grip.
Looking at the testing, the 6.5" 41a remained colder then the 7" 45a. (also, the 7" 45a got hotter when the 6.5" 41a was in the rear then with a matching 7")
But I think a big part of that is that the harder compound and large sidewalls of the 7"s led to them sliding more, stressing the rubber, and heating them up. The shorter sidewalls and softer 41a compound let the 6.5" remained ârailroadedâ around the corners, stressing the rubber less. I donât know tires though, this is wild speculation, and some of that is probably riding style and 4wd
/wall
Enjoy a picture of Ankle Wreacher with 7" tires
I catch them cuddling sometimes, but only when they think Iâm not looking
Opensauce!
I exhibited Ankle Wreacher at Opensauce! @poastoast joined me, bringing his raceboards too.
I expected to have lots of downtime, so brought my steam deck to do TITS software development. However, didnât get to write a single line of code.
I was shocked by how much attention and interest there was from attendees. I blew through the stickers and hundred business cards I made way faster then I expected. It was nonstop talking to folks, and at times there was a small line to talk to us.
Lots of folks didnât even know people raced esk8s. I was presently surprised by the amount of âI have a meepo that I rideâŚâ from folks. Casual riders exist!
Was cool to hear their stories and relationship to esk8ing.
Definitely want to go back next year. âScience Fair for adultsâ really describes the vibe. Hella cool event!
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epic update. 
[ also⌠plea for bite size chunks in the future. ]
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Interesting findings on the 7" BRPs! I wouldnât have expected 1.5" sidewall to be âindirectâ, though BRPs are very different from everything else. The kart stuff has 2.5" sidewalls and itâs very direct and precise when I am pushing the board. Except at low-medium speed going straight, trying to chill. That just feels weird on my setup for some reason, kinda like itâs walking on me. But I think thatâs from torsional flex of my deck and extensions, and the feeling is amplified by the huge contact patch and sticky rubber.
Another thing is that no matter the surface imperfection, aired down kart tires will still find most of the grip. They even allow me to miss my line and go on the rumble strips, since they donât throw me off I just have a bit worse grip on them. Too bad I wasnât very productive building the next version of my own board since about may 
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IIRC the 7" were prototypes. without an appropriate mold for sidewall.
When this happens, what happens to the wheel? Are BRPâs re-tread-able or whatever we would call it? Can you install new foam/rubber on the metal wheel?
When this happens, what happens to the rider ?
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Rough day for BRP at the legend track. This one was from Reggies board. His on/off switch came loose and was ran over by the rear wheel ripping it from the harness. The switch was later recovered from the middle of the straight away. The resusult sent the board into the infield where the wheel in the picture struck a solid object and gored the sidewall.
What they call âdead rubberâ This is rubber that is put down on the track (go karts) and then picked up by hot and sticky tires. If you get out of the racing groove it gets much worse.
Normal to see on most raced surfaces. We would use a âhot knifeâ to scrape dead rubber. This one will clear itself pretty quick at the begining of the next heat cycle.
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Good info, but it doesnât really answer my questions. When the rubber and foam on BRPâs delaminate from each other and the wheel, like in these pictures, what happens next? Is the whole wheel trash? Can you install new foam/rubber onto the metal wheel?
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@BenjaminF Once a wheel is compromised, to the trashcan with it.
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BRP doesnât have a core return? Seems crazy not to
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Aluminum is very recyclable 
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Itâs a plastic rim actually
Really? If this is sarcasm itâs going straight over my head. I know very little about BRP wheels.
Interesting, I assumed it was a metal hub. Makes sense to toss it if it is plastic
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Itâs actually plastic and it does also deform mid corner. I think itâs one of the reasons why BRPs feel like they allow so much slip angle
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