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If you’re having trouble with iron losses, you can try adjust your gearing for less torque. This will reduce the rpm of the motor while you’re cruising, which will also reduce the heating due to iron losses.
Beyond that…there’s a reason I don’t run 7490s on Ankle Wreacher anymore
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Not sure if pole pairs matters, but the 7490 I think has 10 pole pairs instead of the usual 7. So the ERPM is much higher.
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That’s correct
These motors have 20 poles(10 pole pairs) you need the 135kv version for 12s
This is the way!
I am very excited about your tits
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24 slot stator 20 pole rotor is what it looks like to me. im not an expert though just a guy with hot motors haha.
I just swaped them out actually for the flipsky 6384 140kv that I had kicking around. I’ll grab some reacher 6485 when the flipsky get cooked.
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Correct it has 20 poles not 24
it does matter with respect to iron losses.
iron losses come from hysteresis. and eddy currents.
these things are a function of the erpm. (among other things) which ends up being the frequency at which the magnetic fields in the coils are flipping directions.
erpm = rpm of motor * motor pole pairs.
so for the same kv and similar construction a motor with more pole pairs has higher erpm and higher iron losses.
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Past couple months have been all about race events.
Before the con, gave my helmet a nice rattlecan paint job
Pretty happy with the result
At esk8con, I fell 6 times, 4 of which were on Ankle Wreacher, and I’ve got 3 of them on camera.
I fell twice on the slippery patch
Once while getting eliminated from the drag race
And again during the 2nd heat race
cutting these together into a proper crash cut is on my todo list… at some point. We’ll see if it ever happens
Qualified 10th out of 95 racers, and scraped just enough points together in the heat races to make it to the final,
finishing 9th overall. Such an incredibly talented group a riders in the pro final, 'twas an honor racing with ya’ll… competition is really heating up this year!
I love how incredibly different everyone’s board is, and how tuned they are to everyone’s respective riding style. Such a cool part of the sport.
Next up was Electrify Expo Arizona
With the air temperature around 95~100F, both days were about tire management. Mine got all the way up at 75C(~167F) at the end of the 6-lap final 
.
With live tire temps, it was super cool to be racing and be able to know exactly where my tires were at (and confirm what I was feeling) with just a quick glance downward 
I’ll be making a full thread about this system once it’s more mature.
An absolute blast racing with Team SKP, Incredibly proud to be racing with y’all.
Cat break
@HAIRYMANJACK Finally talked me into swapping bushings from KranK to APS in the front. About time too- my Krank had some serious permanent deformation!
Everything came off easily enough (with some heat)
And going back on was just as easy. Swapped the old yellow hardware for some sleeker black stuff too
With the two of us working, and a drill to spin the hanger, we managed to swap out the front bushings in only 90 minutes- woot!
Riding it for the first time last night… I should’ve done this so much earlier!! Instantly felt a faster pace. I was confidently sliding the tires on heel and toeside, not something that I’ve been able to do before.
“I’ve never see your board move like that”
Only footage I’ve got is @R2trivv taking some easy laps, but you can really see how much more responsive the board is.
10/10 would recommend.
What’s next?
I got invited/sponsored by xerace to go race in their European Indoor Championships! It’s a genuine honor to be invited out, I can’t wait!
How am I getting my board out there?
Right now, the plan is to pack the board/tools/charger into a pelican case, check it (sans batteries), and carry-on the batteries.
I’ve got a ton of work to get done to prep before my flight next week;
- Fixing grip tape
- Ripping apart my 8x 4s lipos into 16x 2s lipos to get under the 100Wh limit, so I can fly with them
- Modifying my BMS harness to accept this new configuration
- Building the interior structure to the pelican case (for safe transport)
Going to be busy week!
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That slippery patch was also an issue for me during esk8con, I kept sliding out on it so many times trying to get used to the track, luckily I was able to correct myself before my board went too far.
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Definitely interested to see what you did to make the temp sensors there. Of course, now that you’ve got digital feedback, you can hook up a misting system and 4 heat guns to make your tire temps PID controlled.
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FTFY
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I know people who race usually know how to fall and stuff but it really does amaze me sometimes how somebody can make a 30+mph crash look both painless and almost a little bit fun.
Also I think the drag race crash is my favorite esk8 crash that I’ve seen on camera.
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I’ve got plenty of practice at it 
No binding and trusting my good gear really does all the work. Once I was on my back, I was just chillin, waiting to slow down.
Speaking of, I got another Bionic Action V2. (well, I got a spare for my dad to race with at esk8con. Now, because I shredded my old one with so many falls, I’m now going to use it)
Had to give it a paint job.
Took several days of painting, but psyched with the result. Same paint that I used on my helmet and board… Going to be awesome matching head-to-toe 
Grip Tape
I don’t run a binding, so my griptape is super critical. I think because I don’t run a binding, I stress my grip a lot more then other people do.
Before esk8con, I was pushing Vicious to the limit, having to replace the rear griptape every 4~5 weeks. Additionally, on hot race days, Vicious would melt, accelerating it’s wear even further. If I left the board out in the sun, I’d end the raceday without any griptape left 
Looking for an alternative, I switched my griptape from Vicious to Seismic Skate Lokton 36-grit. It has a paper backing (instead of a vulcunus one), so it doesn’t melt in hot weather like vicious. In fact, the heat-sensitive adhesive actually gets stickier with hot weather! Requires a heat gun to apply to the board.
Even better, this stuff is way shaper (basically glass frit, it’ll draw blood).
And the best part? It’s blue.
A month later of hard racing, it’s showing zero wear. Not an easy feat, super happy with this grip.
Unforunately, it seems to have trouble sticking to my front MBS concave pad.
Over the past couple weeks, it’s actually slid a non-insignificant amount.
It kinda makes sense… the MBS pad has a glossy surface that doesn’t seem like it would be conducive to adhesives.
As a bodge fix, I gave the pad a nice sanding, and re-applied the grip with a heat gun.
Long-term I’ll probably replace the pad with a material that this griptape’s adhesive sticks to better (perhaps 3D printed), but this will do for now.
New Camera
Watching everyone’s POV shots from esk8con this year were sick.
Wanting some of my own, I recently purchased a Insta360 Go3s from a sketchy marketplace deal.
Unfortunately, My helmet doesn’t make mounting it easy. There’s no nice, flat surface to mount it to.
Some creative use of wire snips and VHB later, this was solved.
Pulled the non-stick backing off the Insta360 mount,
And we’ve got a mount that Louie approves of
Man, I love VHB
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This stuff works wonders, I use it all the time at work. Clean your surface, apply this stuff, and it’ll be twice as sticky after it dries.
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Got back from racing at xErace in Prauge! What a blast.
It was my first time flying to a race, so figuring out logistics was a whole thing. Definitely need to figure out a better way next time, this was way too much faf.
Packing For Prague (Batteries)
I shipped my batteries via fedex.
For the batteries, I made a box for them with foam on all sides, reusing the foam that my EUC came packaged in. Can’t be too cautious!
All connectors got Kapton tape. Also threw in this temperature logger (more on that later)
While doing this I notice that the insulation on my BMS connector had started peeling back. Not great
Cut and re-terminated them 
FedEx Tangent
I had a hell of a time figuring out how to actually ship the batteries.
Everywhere I went to quote a hazmat label (to do this “”“properly”“”) just wouldn’t let me checkout.
I ended up buying a general shipping label on Shippo.
On the custom declaration I put “power supplies”. Technically the truth.
Dropping off the batteries at the fedex store, there were signs everywhere about increased scrutiny on packages going to Europe, and they all had to be opened and inspected. Additionally, they specifically couldn’t ship batteries there. Uh oh.
At the counter, the guy asked if there were batteries inside.
I had to answer “Uh… yeah”.
“Leeeeet… me go get a specialist”, and he disappears with my box into the backrooms of the Fedex distribution center
I’m panicking, fully expecting to be denied, trying to figure out a backup plan.
10 minutes later, he pokes his head out.
“You’re good! thumbs up”
Stunned, literally unsure how to react
“good?”
“Yup! It’s on the truck, leaving right now”
No idea how I managed to get so lucky. When I got them in Prague, the box hadn’t even been opened.
Packing for Prague (The Board)
I bought a pelican case for $100 a year ago.
The plan was to build up a foam skeleton to hold the board firmly in the middle of the pelican case, and check it with the airline.
I had to take off my front box extension (Megan/TITS prototype) due to clearing issues (case wasn’t deep enough). Fortunately this was pretty easy, and I happened to have a perfect bubble wrap thing for it to travel in.
Unfortunately, reality derailed my plans. Even paying an overweight fee, the maximum weight It can be is 32kg (70lb). With just the board and tires in the case, I was pushing 36kg(80lb).
With only a few days to go, plane-checking was my only option, so I had to somehow remove a bunch of weight. The only way I could think to do that was to remove the rear truck/motors assembly. Undo the phase wires and the whole rear just rotates off at the hym.
I had enough “spare” weight to throw in all 4 wheels and my safety gear.
(turned out the scale I was using was quite inaccurate, and I was ~2.5 kg overweight at the airport . Fortunately the attendant was super kind and pretended it said 32kg 
)
I also through my larger tools (wrench, allen keys) in the pelican as well.
In my carry-on, I had my Roger Charger, rear trucks/motors and front box (Megan/TITS). And clothes. (which I neglected to pack ANY socks)
Bye buddies
I felt silly walking thought the airport with 100lb+ of gear
Travel was uneventful, everything arrived in one piece. Hell yeah.
Reassembly in Europe
My hotel had a comically tight staircase for my to carry my heavy af pelican case up/down
After a day of R&R in Prauge, It was time to reassemble the board.
The G300s use Bolted Spade connectors for the phase wires.
As I was tightening the last phase wire down, it ROTATED.
I prayed that it was repairable, and asked around to see if anyone had a high-powered soldering iron that I could use , as I started pulled the G300 out of the board
@adrenalinskateboard responded to my call for help and invited me over for an evening of totally-not-stressful repairs and alcohol.
Disassembling the G300
I was feeling “great”
That said, could be worse?
We reflowed the joint on the backside of the PCB, and that seemed to work!
Not before we melted one of the rubber o-rings though. nbd, Ankle Wreacher was never going to be waterproof anyway 
Getting back to my hotel at like 2am, I got the G300 back on the board and working, ready to race. Lets Gooooo
@adrenalinskateboard You’re and absolute Chad. You’re appt is amazing, your board collection inspiring, and you saved my whole race week. I owe you 
Unfairness
I went through all this, Dylan Bell just checked his board. Luggage tag around the binding. 
I’m in Prague!!!
smattering of media from my week in no particular order
Kart Planet is so much fun
The Race!
What. A. Blast.
6 back-to-back races. I think we had ~12 minutes of racing within a span of
and hour of so?
by the end of it, we were all brutally exhausted. It was borderline an endurance event! I was just focused on not falling and crossing the line.
I was right on the edge of podium the whole time, and I wanted it.
In the last race, Tas put down a great time, beating me to the podium by 0.15s
Across 6 races the difference coming down to be that tiny?? I can’t even be mad. Great racing, everyone. Fucking fantastic time.
The Return
After a private night tour of the city from David, it was time to pack up and go home.
Got back at the AirBnB around 3am, with my flight leaving at 9am.
Gave me barely enough time to disassemble my board and get everything packed. No sleep for me that night.
The bag check person wasn’t as generous this time, so I had to do some reshuffling at the airport. Wasn’t too bad though.
The flight back was cool. I got to fly in the massive double-decker A380,
where I had entire rows to myself
Got my board from bag check in LA without issue, and made it home. Great conclusion to an amazing trip.
It was such a pleasure meeting so many cool people out there, too many to name. So many people from such diverse backgrounds, and I wouldn’t have meet y’all if it wasn’t for this little hobby.
@davidpilny Thankyou so much for inviting me out there, it was a trip of a lifetime. Not one I’m going to soon forget.
20 Likes
Cool Temperature Data
I mentioned that I put a temperature sensor in my battery box. I also put one into my pelican case! I was curious what temperatures I’d be subjecting my board equipment to.
These are neat one-button modules that record continuously, and can be plugged directly into a computer to get the data it records. Shows up as a flashdrive with a csv file.
But surprisingly, my board didn’t get as cold as I was expecting. When I picked up my board from baggage claim, it was still cold.
Definitely a temperature swing, but nothing that it wouldn’t experience on a cold/hot day of racing!
Interestingly, the fedex batteries never went much beyond room temperature
Cool to have data showing this isn’t something I need to worry about 
Raw data for completeness/archive
BoardRaw.csv (127.3 KB)
BoardReport.pdf (32.0 KB)
BatteriesRaw.csv (93.2 KB)
BatteriesReport.pdf (23.7 KB)
So, it’s two weeks later and my board still isn’t put back together.
Batteries
Because of my short packing time to catch my returning flight and my neglect to pre-print a return label, I opted to leave my batteries in Europe with Bence. Might keep em out there for any future Racing, or might try to sell them at a discount(anyone interested?), TBD.
I’ve been holding on to @HAIRYMANJACK 's old SMC packs for a couple months now(They were for Super Duality).
Quincidentally, they are the same ones and quantity that I run in Ankle Wreacher.
I bought them off him to put into Ankle Wreacher. They’ll be the batteries for this board for the foreseeable future. Does mean I’m back up to 16s (Not that that changes anything)
Step 1 was to replace the QS8’s with AS150s.
SMC Quality
Taking them apart, I was shocked by the quality of some of the solder joints in here. Apparently these were soldered by SMC. Interestingly, only the positive wires were questionable, all the negatives were fine.
Something to be aware of, I guess.
One podcast later…
G300
Reassembling the rear truck, I ran into exactly the same issue with the bullet connector becoming detached from the PCB. 
I tried giving it the same reflow treatment, but it didn’t hold
I’ve sent a message to @YUTW123 to see if I can get a replacement part, but I need the board working in 5 days for the Legend Race… So I’m probably going just just need to try again.
Until then, the board continues to sit across my coffee table.
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Definitely gonna wanna add a intermediary connection for those going forward. Seems like the g300 wasn’t designed for those connections to be cycled often
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