Update on new wheel (more comfort, speed, & grip) testing and Austin Group Ride feedback!

General Discussion
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Gummies was my exact thought when I saw the first pic too. But the cool thing here is that I will actually be able to fit these gummie like wheels onto my set up since Trampa only has the 125 mm which is flippin huuuuge! Love the concept and idea, the ride as well so hoping these end up working out and maybe even coming in some different sizes and duros to set everyone’s needs (and also everyone’s available wheel clearance)

2 thumbs up for the inspiration and will keep my fingers crossed that it’s achievable

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@Jansen Thanks!

We asked a lot of riders on what they wanted to change about their Board if they could bolt on a wheel (no other mods). Here is what riders said:

10-26-18%20survey

We got a good amount of data entries, but always looking for more. If you want to cast your vote, then enter it https://docs.google.com/forms/d/1eeYF0bdTHigB_eqOiBB-m8a0ELdu58JEhQpoDd8xYJU/edit

New Focus on: Comfort and high speed

Let’s give people what they want, but at what trade off?

However, we’re not sure what trade-off people are willing to take if they get a wheel that is more comfortable with capability of higher top speed. Adding comfort means more rolling resistance and a much softer durometer. So here is another poll designed to ask what would you be willing to trade? Enter your vote here: https://docs.google.com/forms/d/e/1FAIpQLScPSmE1X22vdOZET2vP08JsfyX2ZTIqHZteGZYjjxfNgpra_w/viewform?usp=sf_link

Bench marking durometer

One thing that affects ride quality is softness of the wheels. So let’s measure the durometer and deflection of the popular wheels on the market. We measure the Caguama (Kegels data coming soon). These are the 83A durometer wheels and it consistently comes in at 90.5A on all four wheels that we have. These are sold as 83A shore, but polyurethane does have a tolerance variance. We’ll be comparing our design to the Boa Constrictors and Kegel in the following blog post.

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Caguama Deflection Vs. Force Curve

Comfort is also attributed to compliance of the wheel. So we measured that too for a bench mark. For Electric Board riders, Orangatang are the key choice here. We’ll be performing this same test on the Kegel and other wheel choices, then overlay the data.

%20Force

Simply put, the Caguama wheel is pretty stiff. When you’re on your board, you’re traveling at 22mph. You’re 200lbs. You and the board is 215lbs. Each wheel has a distributed load, each wheel is under a load of 54lbs. It takes nearly 75lbs for the wheel to deflect .1". These wheels pretty much have no give to them.

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Inertial Calculations

Based on our engineering software (we solid modelled each wheel), our inertial calculations relative to each wheel is as follows:

Kegel 80mm is 2.0, our wheel at 100mm is 3.0, and BOA 100mm is 5.8

This would mean that we’d be able to achieve a higher top speed but with similar acceleration of the Kegel wheels (bolt on comparison). Exactly how much less acceleration? We will have to determine that when we start testing in a couple of weeks. Basically, the current design can accelerate nearly twice as fast as the BOA and a little slow acceleration than Kegel.

First prototypes and 3D printing

We’re using a 80mm polyurethane of our own resin and the results look good. We don’t have any testing on acceleration, top speed, or comfort yet, but that will be coming in the next blog posts. Mostly, we just have one wheel so far and we have to spend the next couple of days creating the wheels. They typically take a day for us to hand make each wheel.

The specs of these wheels are 100mm diameter with a 40mm contact patch. Stock Kegel Wheels are 233g and our wheels are currently 197g. We think the weight of our design will increase closer to the Kegel weight, but not sure exactly how much right now.

We will be testing soft durometer and different levels of grip. It’s still early to say and these our first prototype wheels. Based on our motorsport experience, softer compound means higher grip, so we can get away with less contact patch. If the wheels are more compliant with softer durometer, then that means a more comfortable ride. Wheel wear is of course going to be higher too. However, we’re still figuring out all the sensitivities in the design.

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Dynamic and Static Testing Metrics

What dynamic and static testing metrics would you like us to measure when comparing our design to the other wheels? What other wheels should we test against?

Dynamic Testing

Bumpiness, acceleration, top speed, range, grip, surface transition. Anything else?

Static Testing

Weight, durometer, inertia, Deflection vs. force. Anything else?

We’re planning for a big testing session on the 7th of November. Who in Austin, Texas wants to join us and have some beers and go riding (when we’re not drunk…)?

Want to keep track and get a big discount when we get this to market? https://free-range.landinglion.com/rangewheels/

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Also, I’ll take a look at all the comments before I had posted this recent update sometime this weekend. Talk to you all soon!

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@Jmding thanks for the explanations and articles. your math shows the wheels have about a sixth as much rotational energy as the linear kinetic energy of the system. i still think there’s an appreciable gain in performance to be had there, we’ll find out more soon.

PS where did you get the number 2871 gcm^2 for wheel inertia? i’m trying to get similar values from CAD models and getting anywhere between 2000 and 5800 gcm^2. it’s interesting to see how much just a little more diameter can add these inertia values!

@Deckoz you say 125 mm wheels are amazing, but what makes them great for ride quality? Is it the extra diameter overall, the extra thickness of the PU, the extra inertia, all of the above? i’m curious to know what people think.

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Meshmunkey, thank you for being open to the idea and taking the time to read my posts! I really appreciate it. Sadly, I was really off the mark.

The KE of the linear motion is 5 kJ, 5000 J (I knew I shouldnt have used the “k”, its too easy to miss). The KE of the angular motion is 0.72 J. So yeah, negligible. Even if you reduced the moment of inertia to 0, you still wouldn’t be able to tell at all.

This still surprises me, as from my experience pushing boards, 77mm big-zigs felt harder to push than 70mm grippins. It must have been placebo.

I estimated the moment of inertia earlier, by ignoring the plastic core, assuming 100mm OD, 56mm width, eyeballing the ID, and using a 1.04 g/cm^3 density of urethane.

I mess up the calculator step all the time, so its good to see that your results bound my estimation.

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@dth2m5 the 100mm wheel will supply about ~80% as much thrust & acceleration as the 80mm…

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It’s the diameter. Gummies(28mm)have less urethane then 107s(36mm).

The gummies weight a little less and feel less bouncy - I imagine because the thinner urethane. Bumps feel less harsh because of the larger diameter.

I’m guessing a wheel that was as large(125mm) with as thick of a urethane layer as 107s(36mm), would feel just as bouncy as 107s over bumps, but feel less harsh from the diameter.

One of the weird side effects of more wheel weight is how the lighter the wheel is the easier it seems to tramline when riding over cracks(want to ride the groove) the same happens when a wheel is narrow. The lower the weight of the wheel, the less force the crack needs to pull the wheel in it’s direction. So lighter and bigger isn’t always better.

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@dth2m5 You haven’t read anything we wrote. I’m done suggesting anything to you people. I call dibs on the cool stuff when you liquidate your failed business venture. Never turn down free advice then come back like an asshat repeating the exact same marketing bullshit that isn’t facts-based

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@b264 I understand why you’re angry and I hope you end up having a nice night. You seem very pissed, but I did say I was going to respond later in the weekend. Thanks for wishing that my business fail. I appreciate your concern and contribution. Talk to you later when you’re less aggressive. I also acknowledge that you know nothing about us and so your insults really don’t have any effect on us. Feel free to keep posting negatively, if it makes you feel better. I’ll still keep posting progress :slight_smile: Have a great night!

Doug

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@Jmding oh wow, yeah i missed the k there. those values should represent the kinetic energy at 10 m/s, it’s interesting to see there’s almost four orders of magnitude there. is it fair to apply F=ma to the linear portion of the mass and T=Ia to the inertias, and then couple the accelerations via the radius of the wheel somehow? Hmm, have to think about it some more…

I get a value of 2020 for the kegel and 5770 for the boa, but i’m just realizing those values are based on a density of 1.00 rather than 1.04, so add 4% to those results.

@Deckoz awesome feedback, thanks. based on that, i think the difficulty is in getting good give or compliance without adding a ton of weight. that’s where i think we have the best chance of finding some improvement to be less harsh.

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Yeah, I tried that in the earlier post. But I’m pretty sure I messed it up somehow.

Agreed, 4 orders of magnitude seems too much. I still think there’s a mistake somewhere. After all, car guys care about make wheels lightweight, and I expect the wheel/vehicle ratios should be similar in that application. Something is wrong.

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@dth2m5 and @meshmunkey you should start by listening very, very, very carefull (you come here thinking like engineers… ‘Engineering’ … fancy word) … what you intend it is only a fraction of what is required to come up with a winner wheel; listen carefully and step down from that cloud you are sleeping now… :point_down:

@MoeStooge

Wish you guys the best of luck. Higher top speed, add watts. Longer range, up the watt hr. Grip and ride quality is more important. The proposed wheel has neither of these to offer. Snake-oil salesmen

@b264

Yes; top speed is determined by lots of things and wheel diameter is not something that affects it much because the gearing ratio can just be changed to work with whatever wheel diameter you have. It’s not fundamentally limiting the top speed in any way. Not like something such as power draw limits…

@b264

100mm is too small. 110mm is perfect and can take so many more natural obstacles … like street plates and lifted sidewalks and pavement edges

. . .

…yours … :point_down:

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…been done before. By a company which knows what is required for longboarding, skateboarding and electric skateboarding (ABEC); a company which alone basically invented the big Esk8 wheel of our times, the wheel that today sets the standard for which all are measured (107mm Electric Flywheel). They also had their own share of failures, including a wheel exactly like the one you are now trying to design. One exactly like yours, was created a few years back… and was a failure. So you see, that concept been explored and researched before. You are not inventing nothing new. You are simply making the same mistakes others already did… :point_down:

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…as you can clearly see, they did a 92mm and a 101mm wheel with very similare core design and thin urethane cover as yours… :point_down:

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Don’t be stubborn.

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Heads up, this looks like the wrong deflection test to me. You will test the deflection per unit width this way, but you will need to integrate that over the whole width of the wheel. Deflection will also probably be greater at the edges. Better to just apply a load through a sheet of plywood or similar and measure the total compression, rather than with a point load probe

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Guys, there are standards for doing that kind of stuff. Do a search for ASTM D2240.

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@dth2m5 @meshmunkey @Jmding @Deodand suppose i am trying to climb a 31.5% slope w/ a dual motor board with 10S (37v battery), 190kv motors (0.05ohm), 80mm tires, 16T motor 36T wheel (2.25:1 gearing ratio), 60a motor current limit, 60a battery current limit per motor, 95% max duty cycle, 200lbs rider + board, 0.75 drag coefficient, 0.6m^2 frontal area…

…would switching from 80mm to 100mm tires give me higher top speed & minimal impact on acceleration?

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Prof, from before:

Energy = 1/2 mass * speed^2 + 1/2 moment_of_inertia * angular_velocity^2 + mass * gravitational_constant* height

The wheels dont slip, s = constant * w and acceleration = constant * angular_acceleration

So yeah, the ratio of linear to angular kinetic energy is fixed, hill or no hill. In the real world, in our application where angular energy is 10000x lower than linear KE, I totally agree, going up in wheel size will always negatively impact thrust.

Theoretically if our wheels were orders of magnitude heavier, I still think it would be possible to go up in wheel size but still increase thrust by reducing moment, regardless of hill climb or descent. But thankfully our wheels are not 20 kg each…

This guy explains the physics very well

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can I beta test? :smile:

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how would putting some wheels from a tesla model S onto a board affect the top speed & acceleration?

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Less contact patch and grip has nothing to do with the wheel dropping in the rut between railroad tracks.

For an actual commuter wheel, and not a toy’s wheel, contact patch has more effects than just dry grip, and this would not be apparent from a motorsport perspective

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These Engineers trying to ‘invent the wheel’ when they know scat about Longboarding and Electric Skateboarding are a joke. Theory is important but the streets are not the theory. Trying to create a ‘map’ but the map is not the terrain.

Listen!! :ear: (but we already know you will never listen) :face_with_raised_eyebrow:

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