Hub Motor & Urethane Riding Qualities

ESK8 Mechanics
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Hub motors are here to stay. Not because they are any better or superior than their comparable belt/pulley driven motors, but because it is irresistible to NOT want to stash your motors inside your wheels and make it look aesthetically pleasing. Stealth is cool. Uncluttered boards have sex appeal. Having fewer parts is also nice, as long as the parts that you keep perform well and are readily available and reflect a flexible/open system and not a closed/proprietary system. Most of the people on this site are here because they don’t want to be boxed into ONE person’s idea of what an electric skateboard should be, or only what ONE person wants to produce and distribute. In the “push” longboard market we stick to a couple of known standards (new school hole pattern, 608 bearings, .400" bearing spacings, 1" bushing diameters, 10-32 mounting hardware or equivalent, 3/8"-24 kingpins, 5/16"-24 axles), and the consumer can mix and match and upgrade parts from different vendors as he/she chooses. This is a beautiful thing.

If you trust ONE person/company to make these unilateral decisions for you, then you buy a complete. Rarely is every link a strong one, but as long as everything is “acceptable”, you can ride around and be happy. Most people here aren’t going to be happy with one vision, one way.

As this relates to wheels, my current plans are to support the community with a number of nice wheel options. My experience is that you want a LOT of top notch urethane as a percentage of volume when considering the harder hub/core/bearings inside of them. When I oversized my cores in the V1 Flywheel series, there were only a couple of wheel/hub combos that proved to be viable. When I evolved the wheel and hub designs to include more urethane, EVERY wheel got better. Here are a few pictures of the history of the Flywheel and related big wheels, and a comparison chart showing the depth of urethane as it bears to the size of the wheel and hub. Let me know if your experience is the same or different.

The newer 45mm hub compare to the oversized 70mm original …

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V1 Flywheels with on the left full width (52mm) hubs that are 50mm and 70mm in diameter …

V1vsV2.jpg511Ă—606 88.8 KB

We learned a LOT about oversizing the hub with some the big wheels here …

BigBoyz.jpg454Ă—578 78.5 KB

Some of small and medium hub wheels with wide contact patches

The 83mm OD x 78mm width started with a “Double Wide” Flywheel where I cut and glued two wheels with 4 bearings. Later I used a medium hub with 2 bearings, then a small hub, and then a narrower offset version …

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If there was a wheel bible…this would be one of the chapters

The Gospel according to @ChrisChaput

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Are you @ChrisChaput working for ABEC11? I am for sure, 100%, you must be if you are posting a plastic-molded injected core of the ABEC11 Flywheel and have access to the urethane formulation.

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http://www.abec11.com/about

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he literally is ABEC11 & one of the pioneers of large high-quality skateboard wheels

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@chuttney1 he is abec11

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this is all very SUBJECTIVE

“So bad we never made it”

millions of 50mm skateboard wheels with really hard urethane formulas and similar urethane depths (10-12mm) have been sold to skaters across the globe and they love them, becasue they are better for certain things… specifically tricks due to the light weight.

Rolling resitance & other characterisitcs like “pop” also play a role in wheel choice for pro skaters.

How a wheel feels & what makes it good is VERY SUBJECTIVE

ALSO: the application or the specific use case will always dictate the design constraints

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“Performance” is absolutely subjective, and depends largely on riding styles which progress and change over time. Most of what I’ve targeted was a high level of control at a high level of speed. This is because I love competition and raced in several skate-related disciplines. I’ve raced downhill in packs, single rider downhill for time and/or speed, Giant Slalom, Hybrid Slalom, Tight Slalom, Super-G in water drainage ditches, street luge, buttboarding, push races, LDP, etc. If I’m 100% honest, I’ve also raced downhill inline, and did some short-track speed skating and ice hockey to better understanding “blade” type wheels that take only radial loads instead of the non-radiused wheels that are needed for sideloads.

The great news for consumers is that if a wheel is great for racing, it’s fantastic for carving and cruising and skating outside of competition. And they’re getting the exact same wheels that are being used in racing. There are reasons that virtually no one races on wheels with huge cores and little urethane. They can’t win. They can’t hang in the turns, they can’t handle imperfect track conditions, and they wear out quickly. So if someone looks at “performance” as the ability to out-race, out-maneuver, out-corner, and out-run the competition, I agree.

I personally believe that the performance requirements for electric skateboards are very close to what racers want. You want to have control at speed. You can compensate for not having “fast” wheels by having more power, but it comes at a cost (draining the batteries prematurely). You can compensate for having components with less control by developing more skill, but when someone else has the skill AND the control, they’re gonna win. Some racers are paid to ride a certain product, even if the performance is substandard. And they can even win on inferior equipment. But I don’t want or expect my customers to have to overcome equipment deficiencies in the products that I market. I make products that I love so much that I can’t wait for people to feel what I’m feeling. Not everything I’ve made are studs, but I’ve managed to avoid making very many duds.

I think back to some of the cars in the late sixties and early seventies that had big powerful motors but objectively horrible braking and handling characteristics. The truth is that it’s understandable that they were made (testosterone and all), but they are dangerous. Putting all that power into something that can’t handle it is not a good idea. I need the full package.

We choose asphalt and concrete to be our medium. We choose wheels sizes that are less than 5" in diameter. And we choose to turn using lean-steer. Our wheels are our interface -our connection to our chosen medium. It is a critical choice. And since I’m basically choosing for a pretty large group of people, I’m going to make sure that they get smooth, fast, controlled, and long lasting wheels with lots urethane on them. And when, as, and IF I do some hub motors, they will be very tall wheels indeed.

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Urethane depth really does have a significant impact on the ride quality. I can notice a difference even between 90mm and 83mm Abec11 Flywheels at the same duro (75a, classic)

Side effect of lots of urethane… The wheels last forever. The 75a Flywheels on my push setup are a decade old now, and still at 86mm after thousands of miles

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Stellar insight. Really glad you have become more visible and accessable to this community. Welcome Chis, thanks for these insights and making magical, unicorn farting rainbowesque, buttery as shit, smooth, wheels of the gods.

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Tell that to Usain bolt, do you think the guy with the silver medal should have gold instead because he had a better running style?

You were the world champion in speed racing because you got to the bottom faster. You performed better, your wheels/gear was probably better too, but that was not the method the judges used to award your prize.

Anyway, this is stupid, Performance can be both Subjective & Objective…

Objective performance can be measured and there can be a winner, Subjective will lead us to have stupid arguments.

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They say that there are no stupid questions so here we go… :slight_smile: I never ride a longboard… did try skateboard few times but that was it. Now I want to build my eboard of some sort and I can’t understand why longboard wheels are shaped like they are? I belive 99% of videos that I saw was just riding straight with few not very hard turns. A big flat surface in longboard wheel = more friction and resistance, right? So maybe they should look more like roller skate wheels or something in between? Please guys educate me :wink:

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First of all, there are a LOT of counter-intuitive realities in skateboard part design, and you just mentioned a BIG one. It’s kind of funny, but some of the WORST ideas in skateboarding come from really smart AUTOMOBILE engineers. I think this because they don’t differentiate from the lean-steer skateboard and the manual-steering cars, go-karts, and reverse trikes. They also tend not to understand that a gravity or push vehicle is grossly underpowered compared to a vehicle that weighs way more than the rider and has an awesome amount of power available to him, as well as a suspension system and the ability to countersteer. BMW Carver anyone? Rubber radiused tires, huge metal cores with swing arm type steering on a heavy metal brick of a deck? No thanks … no ultimate driving machine there.

Rubber and/or pneumatic tires can provide a tremendous amount of traction and control (Psychotiller’s Six Shooters and Carve Board tires come to mind) but if you don’t have a motor, you better have a chair lift and a steep hill around because they ain’t no fun to push. At least the Carve Boards are like that. Only tried Six Shooters under power and me likey.

On (dry) pavement the urethane wheel can be magically fast and smooth and you can dial in the amount of traction and/or drift that you want. You can make fast wheels that stick like suction cups, and fast wheels that you can push sideways, but in either case you won’t get greater “rolling resistance” with a wide wheel and/or wide contact patch. Just the opposite. Think of it this way. You’re driving your car on grass, sand, and dirt roads. Do you take the “road bike” path and use tall, narrow, highly inflated tires on tall stiff rims to “minimize rolling resistance”? Oh hell no. That’s about the worst thing that you could do. You want soft, wide, underinflated tires that keep you from sinking into the medium. Skaters should treat the board like a dune buggy in that regard. From a dead stop, my board with SIX 83mm tall ultra-soft high rebound 74a Centrax that are 78mm wide each will out-roll a board with FOUR smaller wheels of the same urethane. As I said before - counter-intuitive. 99.9% of skaters don’t know this, nor do they want to accept this. They will quote books and say things such as, “the smaller wheels will overcome the moment of inertia more readily and accelerate more quickly”. And they would be dead wrong.

In the mid seventies we started adapting roller skate wheels into skateboard wheels. Narrow 52mm medium durometer wheels. They only had to be narrow for roller-skating because of the size of the human foot. Too wide and they’d rub. Skaters begrudgingly increased the height and width and softness and rebound of the wheels until it was clearly demonstrated to be a winning combo. On super smooth ramps and concrete, you want a harder smaller wheel in the same way that you want the balls in your bearings to be steel and not rubber. You give up on traction but then again, you don’t need a lot of traction to land a trick or grind coping. That’s a different medium altogether.

Given gobs of high rebound urethane on a steep asphalt road and you can roll at over 85mph without a motor and start thinking more about better aerodynamics to go even faster. There are good reasons that no one is using a narrow inline wheel on a skateboard, even for going straight. They suck. If you like speed, traction, and control, go big, wide, soft, and high rebound.

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The innovators dilemma… Much of what Chris postures about in a broad sense is discussed here by C. Christensen. (It’s a pretty good read I think, dated but timeless). Clayton discusses the disruption of industry using historical models and attempts to formulate why some business makes it though disruption and some don’t.

As for subjective or objective, in the sciences we break stuff up in to two broad categories, quantitative and qualitative. In the former we look for hard data things we can measure and repeat. In the later we might do a interview… If you get a big enough data pool (n1 (sample size) doesn’t mean a lot) both can be valid. It’s just: I did this once and this happened so… doesn’t mean much on it’s own except for a persons experience. Maybe this one person has cred, and a mass of experience so it might have marketing appeal. But that’s not science and we are blurring the two.

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Thank you very much Mr. Chaput for your explanation but…

Yes, but we do have motors right?

Yes, but we are not talking about that kind of speed and again we do have a motor (or two :slight_smile: )

Ok, so two identical boards (same size, weight…) with different wheel sets and we let them go from the same hill at the same time… which one will go more distance?

Well maybe this is the reason that you have mentioned but thats my point and doubt here. Maybe there should be new approach to this? I belive that there will be more and more people like me who never ride a skateboard or longboard and eboard is totally different thing. For most users it is a way of commuting and that is going to be the mainstream. The industy is where it is and its easier maybe to adapt existing solutions than come up with new ones or maybe it’s a matter of scale at the moment? This is my DIY thinking not based on any science and not even on riding a longboard once, so I’m a bit keyboard warrior here but just want to understand :smiley:

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Yes, electric skateboards have motors. And they have batteries. I’d rather have my motor taking small sips from my power source because I have very efficient wheels than taking huge gulps because of inefficient wheels, i.e. wheels with a lot of rolling resistance. What I’m saying is inflate your “normal”, narrow car tires to the right level for better gas mileage on asphalt, but if your in a dune buggy, don’t use highly inflated narrow tires. Skateboards are dune buggies. Ignore that analogy at your own risk.

What I’m saying as an approach is to do actual testing in real world conditions. Go to a downhill or street luge race and try to find hard narrow wheels without much rebound. Hit corners at speed on an electric skateboard and tell me how comfortable you feel on small hard narrow wheels. The difference is easily noticed.

And when the only difference between two boards is the wheels, and one board pulls away from the other from a dead stop AND has better traction and control and speed through the corners, which one do you want to ride? Better is better. It’s not rocket science.

Gravity is simply a different type of motor, and bad wheels hurt performance whether the force is gravity or the force is a brushless DC outrunner motor or a hub motor or a different direct drive motor. Most electric skateboarders will not go as fast as downhillers, but downhillers know how to design boards that are stable at high speed which means that they are safer and more stable at “electric” speeds. And believe me when I tell you that there are plenty of electric skateboard builders out there that are not at all content to be slower than gravity boarders. It’s like building cars that are beaten by a horse. A ONE horsepower horse. As we continue to go faster and faster, our wheels become increasingly important to us, and so are our trucks and bushings which are not getting a lot of attention right now. It’s a system, and you are only as strong as your weakest link.

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How about this?

107mm 74a Abec11 Reflex thane, with a 63mm diameter hub for an R-Spec Hub Motor, would give 22mm of urethane depth. That would result in such a smooth and plush ride. I suspect it would feel similar to how good a soft Abec11 90mm Flywheel feels (22.5mm urethane depth). It would also cut down the weight (and cost) of the monstrous 107mm Flywheels

Best of both worlds. That’s a collaboration product I would buy in a heartbeat

@ChrisChaput + @onloop

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@ChrisChaput Thank you for this info. Your core design is brilliant and I can see now why your rubber never detaches from the core.

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It’s not so much that I have a bad taste from the automotive engineer, it’s the abomination that he created, called a “next gen skateboard”, and then peddled to the unwitting public using engineer-speak and his company’s reputation as his marketing ploy. The board is a turd on wheels. Bad wheels at that. I’ve seen other who created these dual swing arm trucks and they were adamant about how they were able to keep their outside wheels in contact with the ground during a turn. They were doing all these desktop demos where a dollar bill slipped under their wheels was harder to pull out with their swing arms on. They never showed it compared to a normal truck, they never showed it under a proper load, they never showed it beating a different system, and they never showed it any “real world” conditions. It’s so frustrating to listen to a staged “win”. That whole concept was based on the idea that in a turn, most of the weight is transferred to the outside wheels as it is in a CAR. A car with a steering wheel, not a lean-steer vehicle. They were literally telling me that my outside wheels were experiencing as much or more force as my inside wheels. I asked them to explain how much force was on my outside wheels when I carved past them with both my outside wheels completely off the ground and they told me that I was just doing that to be a prick. Seriously, there was ZERO force on my outside wheels and they denied it was even happening.

I told that them that if you DON’T put more force on your inside wheels, you can’t and won’t turn in that direction. The simplest concept, but they had an agenda. To sell whatever they were making.

I had a HUGE financial investment in the original Flywheel hubs and wheel molds. I desperately wanted big cores with small amounts of urethane to function at a high level. They looked awesome, like a car with crazy big rims. But it doesn’t take genius to know what that tire feels like going over a pot hole. But even on smooth surfaces the big core and absence of unsupported urethane that could deform and stay in contact with the road meant poor traction. And OF COURSE we tried the cheap fix - to use super soft urethane in the hopes that it would be good enough. Nope. Not even close. We tried duros less than 70a, and marketed wheels in 72a. No amount of engineer-speak or marketing hype was going to make that wheel/hub ratio a viable high-performance contender.

At the end of the day, I had to bite the bullet, create a big, expensive, multi-cavity hub tool, and create a set of wheel molds for every different size. I was racing, and I wanted to win more than I wanted to make money. One hopes he can do both. And as the style of riding changed from controlled slides in the turns to pre-braking better and then “railing” turns, we moved to even smaller cores, wider wheels with more square and flexible lips.

It seems as if there is a big conversation of distraction that pulls away from looking at something at the heart of the matter here. We talk about windings and KV ratings and torque and “maintenance”, as if those are the only things that matter. What about the ride? I’ve never been able to put a thin band of urethane around big hard hub and have it feel good or perform well. I still own the big hubs and can make any mold I want. If speed is all that is important to someone, he can put some big ass motors on his trucks, slip some rubber bands over them and be happy. He won’t be able to stop as quickly which is problematic since speed is his thing, but safety isn’t the number priority for speed demons. He’ll be able to drift his back end well, especially on rough terrain because that back end be a-hoppin’. Tokyo drifters rejoice.

I am not anti-engineer. I am pro-reality.

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BMW street carver is what you a referring to???

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