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Sorry, f4 thread, not wheels.
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A wheel like that in 99 f4 would obviously be grippier than classics. That fact about friction does not work with skate wheels. We are grinding the wheels down, wider contact patch means more material to wear down, which means more grip.
That does not count as backing your claims. You are just asserting that the surface area does affect the grip.
Oh shit, I missed that. No I didn't back them up, but I still stand by it. More material to wear down equals more resistance equals more grip.
And since you don't back your claims up, we can just continue to ignore them.
Engineer here with a background in physics, applied science and applied maths. I've done the maths, was a while back but did it nonetheless.
More area = more grip as the coefficient of the material has an exponential curve based on force (aka rebound).
Breaking into a slide will be more difficult but maintaining said slide will be easier. Vice versa on the smaller surface wheels.
That being said, we are working with very small margins when comparing same compounds. Biggest difference you could make is based on weight and the angles/force you approach the slide. Also wider wheels will be more controllable as it would want to normalize quicker, and smaller wheels will be more difficult to normalize.
I know this is difficult to understand, cant argue the theoretical science, but there is a big difference in theoretical science and applied (assumptions/fixed variables).
So what you are saying is that the coefficient of friction is not constant with skateboard wheels but increases exponentially with increasing force? Or increasing force per unit of area? But the force stays the same. Force per unit of area decreases with increasing area. Are we talking about deformation of the wheel material under applied force here? If skateboard wheels were to deform enough under force to make a difference, wouldn't a narrower contact patch then provide more grip due to it deforming more as the force per unit of area is greater with a narrower contact patch?
Can you provide some more info on what you're saying as it's the first time I've heard of such and didn't really understand what exactly you were trying to say?
I'm not an expert, but I've read a bunch about contact patch vs friction on racing tires and what I can see is that dynamic friction for objects that deform is a complicated science and there are deviations from the normal models of friction, especially when you look at the shape of the object and how energy and vibrations dissipate. Also transferring energy among something with rolling inertia plays a roll (pun!). I'm not saying the opposite of what you are saying is true, it's just a murky area until we start stacking up peer reviewed studies on powerslides because of all of the variables in real world situations.
Friction with deforming materials sure isn’t as straight forward as friction with essentially non deforming materials. Car tires are far softer than skateboard wheels though and have 10+ times as much force weighing down on them and are filled with air. They’re pretty much engineered to deform to increase grip. I don’t think the deforming argument really applies to skateboard wheels. Even with car tires it’s not apparently all that straight forward that wider tires will increase grip. I’m no expert on that but I think the width is more related to tire durability, that it doesn’t rip apart so easily with the forces it has to withstand.
Haha. Sorry but this is very difficult to explain, hence the theoretical vs applied science. I also work for a living now and dont really dive into these things so much anymore.
Theoretically the the friction coefficient is linear and keeping force (weight) the same the contact area will have no effect.
In practicality, the friction coefficient is not (or rather the equation), there are other forces at work aka wind/drag, magnetic forces between the materials (wheels and surface) as well as the digging into the surfice (small wheels will dig more into the surfice), even deformation due to these forces on the wheel. Now all of a sudden this simple equation of frictional force become a new beast and the wheel shape/size plays a bigger role. You can argue each force individually but in the end bigger = more friction.
This is why F1 racing cars have bigger conical fulls and not biscuit wheels, deformation, drag, digging into materials actually makes a big difference on total friction. More so on racing than skateboarding wheels but the same principle applies.
The human body is crazy though, you can feel the difference. I have F4 classics 53s and lock in 55s. The 55s slide way nicer but with more effort than the classics.