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.
@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… 
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
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…
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 …
…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…
…as you can clearly see, they did a 92mm and a 101mm wheel with very similare core design and thin urethane cover as yours…
Don’t be stubborn.
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
Guys, there are standards for doing that kind of stuff. Do a search for ASTM D2240.
@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?
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
can I beta test? 
how would putting some wheels from a tesla model S onto a board affect the top speed & acceleration?
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
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!! 
(but we already know you will never listen) 
the website claims:
"100mm diameter for increased top speed
Designed for better comfort over stock wheels
Designing for similar stock wheel acceleration"
and:
"Higher Top Speed
Increase your top speed without sacrificing acceleration.
Our design features a larger diameter and are the lightest wheels on the market."
@dth2m5 so are you planning to update the site to reflect the 20% lower thrust & acceleration a 100mm wheel provides compared to an 80mm wheel?
This is clearly 100% unadulterated Marketing Bullshit 
with little basis in facts.
This is snake oil, plain and simple. This has just proved it.
@professor_shartsis I’d have to look into your model some more, but I assume it keeps all variables other than wheel diameter constant? Are you able to modify the acceleration to account for the change in moment of inertia that different designs have? As Doug’s second update mentioned, we’re somewhere close to an 80 mm wheel for inertia, but with the benefits of a 100 mm wheel. If the inertia is at all higher, of course that’s going to reduce acceleration, our goal is to minimize that effect.
PS I’d love to mount up those Tesla wheels! Might hurt acceleration a bit tho…
yes, if you use these formulas and plug in the appropriate values (80mm instead of 90mm & 60a motor current limit instead of 100a & 2.25:1 gearing ratio instead of 2.375:1 gearing ratio) it will show the same results as the graph:
in the above, it assumed there is no difference in moment of inertia at the same ground speed between the 2 types of wheels (giving the 100mm wheel a supposed advantage), and yet the 100mm still has 10% lower thrust than the 90mm. the reason is with the larger wheel you are changing the distance of ground traveled in meters per motor rpm.
the motor torque per amp is determined by the kv. the max current is determined by the controller settings. the torque multiplication to the wheel is determined by the gear ratio. the thrust is determined by the relationship between the wheel torque and the wheel diameter.
if you truly want to increase the top speed without sacrificing acceleration and efficiency then you’ll have to increase the voltage of the battery pack, not bolt on a larger wheel diameter.
@professor_shartsis as a thought experiment, what if you decreased the moment of inertia of a wheel but keep the diameter the same? physics says you would be able to accelerate faster (to what degree? not sure) but that isn’t captured in your model as i understand it. these trade-offs are what we’re hoping to capture through parametric testing of a variety of wheels.
@meshmunkey suppose I have a wheel with 1 meter radius, and 1 Newton meter wheel torque, the vehicle thrust will be 1 newton.
now suppose i have a wheel with 1/2 meter radius, but also 1 newton meter wheel torque, the thrust is 2 newtons, but the distance traveled per rotation is only 1/2 of the 1st wheel. (same amount of work is done per rotation because work is force * distance… we get twice the force for half the distance)
how about a wheel with 1/10 meter radius, but also 1 newton meter wheel torque… thrust: 10 newtons. (distance traveled per rotation compared to 1st wheel is 1/10)
take a look at equation #5 at the following link:
thrust affects linear acceleration via F=MA, therefore A=F/M
increasing the wheel diameter means there’s less force/thrust, and if there’s less force, then there’s less acceleration.
according to the above equation, what happens to the wheel thrust as you increase the tire diameter?
it’s the same as the principle of leverage:
F * L = W * X
or
F = (W * X) / L
or
W = (F * L) / X
^if you want to compare the above diagram to a wheel, F is the wheel torque in newton meters, L is 1 meter, X is the wheel radius in meters, and W is the vehicle thrust in newtons.
… You don’t need parametric testing to figure this out. It’s pretty much an entry level physics question. Even a simple thought experiment can help you see how obvious it is that wheel inertia wont matter. Imagine a worse case scenario where all the mass of the wheel is in the outer rim, this mass distribution causes the highest moment of inertia for a spinning disk(ring). Now imagine as the wheel spins part of the bottom of the wheel is in contact with the ground moving at ground speed, the top of the wheel is rolling back around returning and moving at twice the ground speed. If you imagine each section of the wheel as a particle like this you start to see that mass in the wheel worst case contributes twice as much to inertia as rider/board weight. Wheels simply don’t weigh enough to contribute appreciably to overall board inertia.
Stop talking about “parametric testing” and “decreased wheel inertia” and do the basic physics. If you want us to believe absurd claims I’ll need to see the physics. If I sound annoyed its because I have to assume as an engineer you already are aware of this and are being intentionally misleading to try and create marketing hype around your product. Just make a kickass wheel and then market it based on the fact that its awesome and not based on made up physics and leaning into your day jobs to validate the claims.
They said “aerospace and motorsports engineering, and more recently with Tesla Motors”. This implies meshmonkey has a degree in engineering and was hired by Tesla as an engineer to do design work on wheels. I can’t describe how strongly I doubt that.
i think the wider a wheel is the less likely it is to dip into a crack in the sidewalk (or train tracks) if i’m crossing at 45 degrees…
@MoeStooge in the next updates, we’ll just focus on the progress. My bad if I made it too sales-y. I was trying to avoid that, but clearly I didn’t do that enough.
