EMF / Jacob hub motor polyurethane development

Ok ill copy you on it

count me in, 97mm or 100mm or 107mm…or 108mm lol

black works, any color fine by me


I found another polyurethane supplier today from which I can get the raw materials for under $100 including the release agent. I will place the order later tonight. This stuff is pretty good has a working time of 3 min and fully cures in 1.5hrs with a 80a duro.

I’ll take a set of tires in whatever size everyone else wants.

Lets go with 107mm and wear it down to a smaller size as the years go by.


Sounds good - I’m in for a set. Anybody know of any good 107mm standard wheels for the front trucks other than the Abec 11’s?

Good point, maybe 97mm would be better so we have the option of running clones too. Plus, clones come in black too, so they would actually match. I’ll cast my vote for 97mm.

Ditto (that means I would like 97also)

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I don’t know if I said this all before here but Bjb enterprises has room cure two part pu that can be gotten in small quantities. You’ll need a good vacuum pump and chamber and I’d get stuff that has a working time / pot life much longer than 3 minutes and it can take a lot of time to get everything well mixed, degassed, and into the mold. The longer the better for that for convenience and the longer the cure time and pot life the better the working properties seem to be

In my looking a polycarbonate 3D print core is possibly the best high heat resistant 3D printable core. Aluminum as a heat sink core there’s nowhere for the heat to go and maybe also would add to the obstacle of pu’s mechanical properties deteriorating with the heat. Think it’s best to have a non-thermally conductive core…whatever will allow the core to stick well to the pu and keep the heat away from it. Almost all pu deteriorates around a stated 170f. Pu is said to stick well to most things but with the mix of heat and stress…hopefully the polycarbonate sticks and holds. That’s my plan as well. If it doesn’t hold you could use a hard pu as the harder stuff is more heat resistant and pu sticks great to pu. A hard pu is typical as a core. All the pu I’ve seen is supposed to sit around for maybe 30 days to have its full mechanical properties. 80 duro will soften with heat U can also get high duro silicone around 50 duro for the mold from bjb. All and all expect to spend maybe 400 including pump, chamber, silicone for mold, and a minimum of pu.


Yeah, ditto 97mm then as well

Fair point on the lack of 107 alternatives to ABEC. I will go with whatever works, but prefer the 107mm. Also much prefer the ABEC thane to most clones, but you don’t get much color choice lol.

@Alextech hey would that work on the bub motor you sold me?

Guys so far im ok with any diameter but Alex is funding the innitiave through the manufacture so the money man calls the shots. The design sent out several days ago is for a 100mm wheel.

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That makes sense, I can make any of those work. 100mm fronts could be my 100mm MBS ATLB wheels. Or 107mm match with ABECs or 97mm which are pretty much 100mm so can match either way and not notice.

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Thanks for the heads up on the process. Ill look into those leads you provided. For now im working with less than 100 dollar budjet until the first working protype is completed.

Yes! They will work with them.

I did one in house yesterday in 80a duro and I’ll post the pictures later today. It’s black 86mm with an outer lip. This time the urethane isn’t sticking so the demold is working good.

It will take several days before it fully cures to max strength but right now it feels solid with virtually no air bubbles.

Still waiting on a responsemail from the Gallagher engineering team.


The lip detail for better carving and protection of the screw heads .


You can see the quality of the urethane at 80a hardness and the fit of the inner core to the motor with no nubs or mods needed.


OK I’m developing the formwork for the 97mm but I was planning on making one extra set of these 90mm if any one wants to be the first tester of the proof of concept prototype. $69 bucks for a pair of 2 wheels or 39 bucks for one wheel. [email protected] is the PayPal just put skate wheel with your user name and drop me a PM.