The Set-up Thread

[Roisto]

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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.

[close]

[close]

That does not count as backing your claims. You are just asserting that the surface area does affect the grip.

[close]

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.

[close]

And since you don't back your claims up, we can just continue to ignore them.

[close]

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).

[close]

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?

[close]

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.

[close]

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.

[close]

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.

Hmmm. Explanation is very vague. You're saying that because of wind/drag and magnetic forces wider skateboard wheels have more grip? Gotta say, I don't buy it. Also wouldn't a narrower wheel digging in the ground cause it to have more grip?

And you're saying that the same principles apply to deforming air filled soft rubber wheels on racing cars and essentially non-deforming hard polyurethane wheels on skateboards? Based on everything I've know about this subject racing cars have wider wheels not because they provide better grip but because they provide better structural integrity and also don't overheat nearly as easily as narrower wheels.

[AngryBlackMan]

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Kinda stoked on this graphic.
Enjoi/New deal impact light 8.5
Venture 6.1 w/bones hard bushings
Spitfire F4 Conical Full 53mm 99a
Modus blue bearings
Modus hardware
Mob M80

[close]

Bro ! Is that a S. Pellegrino sticker ?
I just broke in my 6.1 ventures thy are perfect .
You don’t like the stock bushings ? I haven’t skated an enjoy deck on 15 years . That’s sick you got the new deal graphic .

Yes it is, San Pellegrino FTW
I'm too big for stock bushings so I always change them, that's also the reason I'm on the enjoy deck. I skate the impact decks most of the time.

[Firebert]

I have f4 99 classics and conical fulls and the fulls slide faster and longer than the classics (it wasn't even close in my tests.) That is all the science I ever needed. Proof is in the slide

[UPPERCASEnocap]

A freshie I picked up to try a different wheelbase/length.

[planman]

Freshie just in time for nice winter weather. Super excited for this shape though; skated it outside for a few minutes just now and it felt great. Somehow I always keep coming back to Polar boards.




Polar Paul Grund P8 (8.8 widest)
Same Aces w/o the bottom washer
Same Speedlabs
Same Shiny Bolts™
Jessup
Some Nikes you've probably never heard of

[Hefe43]

And you're saying that the same principles apply to deforming air filled soft rubber wheels on racing cars and essentially non-deforming hard polyurethane wheels on skateboards? Based on everything I've know about this subject racing cars have wider wheels not because they provide better grip but because they provide better structural integrity and also don't overheat nearly as easily as narrower wheels.

F1 cars have wider bald tires for better grip between track and tire. bald tires ensure that more surface area of the tire is in contact with the road/race track. This increases the surface area the car tire has with the track making it safer to drive. The wider the tires, the more the surface area of the tire is in contact with the road/the race track.
The more the rubber tire that is in contact with the ground, the better the grip during turns, acceleration and braking at most times, hence more stable.

[MalHuis]

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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.

[close]

[close]

That does not count as backing your claims. You are just asserting that the surface area does affect the grip.

[close]

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.

[close]

And since you don't back your claims up, we can just continue to ignore them.

[close]

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).

[close]

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?

[close]

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.

[close]

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.

[close]

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.

[close]

Hmmm. Explanation is very vague. You're saying that because of wind/drag and magnetic forces wider skateboard wheels have more grip? Gotta say, I don't buy it. Also wouldn't a narrower wheel digging in the ground cause it to have more grip?

And you're saying that the same principles apply to deforming air filled soft rubber wheels on racing cars and essentially non-deforming hard polyurethane wheels on skateboards? Based on everything I've know about this subject racing cars have wider wheels not because they provide better grip but because they provide better structural integrity and also don't overheat nearly as easily as narrower wheels.

Damn. Believe what you want to bro but if you want to learn something keep reading though.

First of all, yes a narrower wheel will dig into the ground more but that is just one part of the strengths that's being introduced to the wheel, there are many and straight friction is also just a small part of it, i was just trying to bring to light a few (positives and negatives). Again when all is considered and a mathematical model is built, a wider wheel will give more "traction"!!! Now again please understand that the to biggest variables are force and angle of attack. Drag,magnetic strengths etc adds up but is marginal.

Also a polymer is a semi liquid, air and liquid act very much the same under pressure, go ride harder and softer wheels then come tell me deformation has nothing to do with it?

Now for the last time, breaking into a slide will be more difficult with a wider wheel but when sliding the mother fucking equation changes. In fact, i believe because its a harder type compound, when sliding a wider wheel will go further

Thus I agree with @firebert, my lock-ins out perform my classics in sliding, they are however ever so slightly more difficult to get into a slide.

[Bristol_Palin]

Freshie just in time for nice winter weather. Super excited for this shape though; skated it outside for a few minutes just now and it felt great. Somehow I always keep coming back to Polar boards.




Polar Paul Grund P8 (8.8 widest)
Same Aces w/o the bottom washer
Same Speedlabs
Same Shiny Bolts™
Jessup
Some Nikes you've probably never heard of

Are those the Nike sb zoom tre’s?

[TwisT]

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Freshie just in time for nice winter weather. Super excited for this shape though; skated it outside for a few minutes just now and it felt great. Somehow I always keep coming back to Polar boards.




Polar Paul Grund P8 (8.8 widest)
Same Aces w/o the bottom washer
Same Speedlabs
Same Shiny Bolts™
Jessup
Some Nikes you've probably never heard of

[close]

Are those the Nike sb zoom tre’s?

Nike's we probably never heard of? Does he think this is the braile forums?

[jay_nev]

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Freshie just in time for nice winter weather. Super excited for this shape though; skated it outside for a few minutes just now and it felt great. Somehow I always keep coming back to Polar boards.




Polar Paul Grund P8 (8.8 widest)
Same Aces w/o the bottom washer
Same Speedlabs
Same Shiny Bolts™
Jessup
Some Nikes you've probably never heard of

[close]

Are those the Nike sb zoom tre’s?

[close]

Nike's we probably never heard of? Does he think this is the braile forums?

yup it’s the zoom tre 100% in this color specifically haha

[thebacker]

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Freshie just in time for nice winter weather. Super excited for this shape though; skated it outside for a few minutes just now and it felt great. Somehow I always keep coming back to Polar boards.




Polar Paul Grund P8 (8.8 widest)
Same Aces w/o the bottom washer
Same Speedlabs
Same Shiny Bolts™
Jessup
Some Nikes you've probably never heard of

[close]

Are those the Nike sb zoom tre’s?

[close]

Nike's we probably never heard of? Does he think this is the braile forums?

[close]

yup it’s the zoom tre 100% in this color specifically haha

my jealousy is through the roof

[planman]

Haha yeah I was being facetious. Found a pair my size on Ebay for like 40 shipped, couldn't pass it up.

[Roisto]

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And you're saying that the same principles apply to deforming air filled soft rubber wheels on racing cars and essentially non-deforming hard polyurethane wheels on skateboards? Based on everything I've know about this subject racing cars have wider wheels not because they provide better grip but because they provide better structural integrity and also don't overheat nearly as easily as narrower wheels.

[close]

F1 cars have wider bald tires for better grip between track and tire. bald tires ensure that more surface area of the tire is in contact with the road/race track. This increases the surface area the car tire has with the track making it safer to drive. The wider the tires, the more the surface area of the tire is in contact with the road/the race track.
The more the rubber tire that is in contact with the ground, the better the grip during turns, acceleration and braking at most times, hence more stable.

Slick non threaded tires, yes. Wider tires, no, not really due to the tire deforming. The contact area on a wider tire will be wider but shorter. On a narrower tire it’d be the same area but narrower and longer.

More rubber in contact with force per unit of area, the more grip, yes. But as the force per unit of area decreases in proportion with the area growing you get the same grip.

[Roisto]

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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.

[close]

[close]

That does not count as backing your claims. You are just asserting that the surface area does affect the grip.

[close]

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.

[close]

And since you don't back your claims up, we can just continue to ignore them.

[close]

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).

[close]

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?

[close]

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.

[close]

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.

[close]

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.

[close]

Hmmm. Explanation is very vague. You're saying that because of wind/drag and magnetic forces wider skateboard wheels have more grip? Gotta say, I don't buy it. Also wouldn't a narrower wheel digging in the ground cause it to have more grip?

And you're saying that the same principles apply to deforming air filled soft rubber wheels on racing cars and essentially non-deforming hard polyurethane wheels on skateboards? Based on everything I've know about this subject racing cars have wider wheels not because they provide better grip but because they provide better structural integrity and also don't overheat nearly as easily as narrower wheels.

[close]

Damn. Believe what you want to bro but if you want to learn something keep reading though.

First of all, yes a narrower wheel will dig into the ground more but that is just one part of the strengths that's being introduced to the wheel, there are many and straight friction is also just a small part of it, i was just trying to bring to light a few (positives and negatives). Again when all is considered and a mathematical model is built, a wider wheel will give more "traction"!!! Now again please understand that the to biggest variables are force and angle of attack. Drag,magnetic strengths etc adds up but is marginal.

Also a polymer is a semi liquid, air and liquid act very much the same under pressure, go ride harder and softer wheels then come tell me deformation has nothing to do with it?

Now for the last time, breaking into a slide will be more difficult with a wider wheel but when sliding the mother fucking equation changes. In fact, i believe because its a harder type compound, when sliding a wider wheel will go further

Thus I agree with @firebert, my lock-ins out perform my classics in sliding, they are however ever so slightly more difficult to get into a slide.

I’d love to keep reading about this. Can you suggest me some reading that support your views? I can go get some books from the university library or ask some friends who are still at university to get me the articles if you can point me in the right direction.

Also what the hell does angle of attack have to do with friction between two solid surfaces? 🤨

While polyurethane is semi crystalline equating polyurethane wheels to air filled rubber tires seems pretty crazy to me. Also saying that liquid and air act very much the same under pressure leads me to believe you don’t have a very strong grasp of physics. Gases are compressible while liquids are essentially not. That’s quite a difference. 😮

I’ve ridden hard and soft wheels plenty. Do tell me how riding them can make me assess the impact deformation has on grip in skateboard wheels cuz it isn’t exactly evident to me.

It seems to be that you’re just throwing out semi-related fancy terms at me and saying “it is how I say it is because I said so” without actually backing it up in any way.

[camel filters]

^ This is the kind of aggressive nerdery I signed up to Slap for. Kudos to everyone. Please continue.

[mariomister]

Magenta Vivien Feil 8.4
Film trucks 6.0
Pusher Bearing Ceramics
Taste Wheels 53mm full conical
Ashes griptape
some hardware

[FROTHY]

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Sorry, f4 thread, not wheels.

Expand Quote

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.

[close]

[close]

That does not count as backing your claims. You are just asserting that the surface area does affect the grip.

[close]

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.

[close]

And since you don't back your claims up, we can just continue to ignore them.

[close]

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).

[close]

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?

[close]

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.

[close]

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.

[close]

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.

[close]

Hmmm. Explanation is very vague. You're saying that because of wind/drag and magnetic forces wider skateboard wheels have more grip? Gotta say, I don't buy it. Also wouldn't a narrower wheel digging in the ground cause it to have more grip?

And you're saying that the same principles apply to deforming air filled soft rubber wheels on racing cars and essentially non-deforming hard polyurethane wheels on skateboards? Based on everything I've know about this subject racing cars have wider wheels not because they provide better grip but because they provide better structural integrity and also don't overheat nearly as easily as narrower wheels.

[close]

Damn. Believe what you want to bro but if you want to learn something keep reading though.

First of all, yes a narrower wheel will dig into the ground more but that is just one part of the strengths that's being introduced to the wheel, there are many and straight friction is also just a small part of it, i was just trying to bring to light a few (positives and negatives). Again when all is considered and a mathematical model is built, a wider wheel will give more "traction"!!! Now again please understand that the to biggest variables are force and angle of attack. Drag,magnetic strengths etc adds up but is marginal.

Also a polymer is a semi liquid, air and liquid act very much the same under pressure, go ride harder and softer wheels then come tell me deformation has nothing to do with it?

Now for the last time, breaking into a slide will be more difficult with a wider wheel but when sliding the mother fucking equation changes. In fact, i believe because its a harder type compound, when sliding a wider wheel will go further

Thus I agree with @firebert, my lock-ins out perform my classics in sliding, they are however ever so slightly more difficult to get into a slide.

[close]

I’d love to keep reading about this. Can you suggest me some reading that support your views? I can go get some books from the university library or ask some friends who are still at university to get me the articles if you can point me in the right direction.

Also what the hell does angle of attack have to do with friction between two solid surfaces? 🤨

While polyurethane is semi crystalline equating polyurethane wheels to air filled rubber tires seems pretty crazy to me. Also saying that liquid and air act very much the same under pressure leads me to believe you don’t have a very strong grasp of physics. Gases are compressible while liquids are essentially not. That’s quite a difference. 😮

I’ve ridden hard and soft wheels plenty. Do tell me how riding them can make me assess the impact deformation has on grip in skateboard wheels cuz it isn’t exactly evident to me.

It seems to be that you’re just throwing out semi-related fancy terms at me and saying “it is how I say it is because I said so” without actually backing it up in any way.

I would really like to make a study on skate wheel width and friction. I have a feeling the relationship between width and friction isn't linear because as the wheel gets wider, more area is outside of where the bearing is pressing down and it introduces a bunch of variables. Also, there is probably a different relationship for softer, tackier wheels because adhesion works differently.

[rocklobster]

^ This is the kind of aggressive nerdery I signed up to Slap for. Kudos to everyone. Please continue.

I'm sorry for starting this 2 pages back

[yourbreakfsat]

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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.

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That does not count as backing your claims. You are just asserting that the surface area does affect the grip.

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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.

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And since you don't back your claims up, we can just continue to ignore them.

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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).

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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?

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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.

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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.

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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.

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Hmmm. Explanation is very vague. You're saying that because of wind/drag and magnetic forces wider skateboard wheels have more grip? Gotta say, I don't buy it. Also wouldn't a narrower wheel digging in the ground cause it to have more grip?

And you're saying that the same principles apply to deforming air filled soft rubber wheels on racing cars and essentially non-deforming hard polyurethane wheels on skateboards? Based on everything I've know about this subject racing cars have wider wheels not because they provide better grip but because they provide better structural integrity and also don't overheat nearly as easily as narrower wheels.

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Damn. Believe what you want to bro but if you want to learn something keep reading though.

First of all, yes a narrower wheel will dig into the ground more but that is just one part of the strengths that's being introduced to the wheel, there are many and straight friction is also just a small part of it, i was just trying to bring to light a few (positives and negatives). Again when all is considered and a mathematical model is built, a wider wheel will give more "traction"!!! Now again please understand that the to biggest variables are force and angle of attack. Drag,magnetic strengths etc adds up but is marginal.

Also a polymer is a semi liquid, air and liquid act very much the same under pressure, go ride harder and softer wheels then come tell me deformation has nothing to do with it?

Now for the last time, breaking into a slide will be more difficult with a wider wheel but when sliding the mother fucking equation changes. In fact, i believe because its a harder type compound, when sliding a wider wheel will go further

Thus I agree with @firebert, my lock-ins out perform my classics in sliding, they are however ever so slightly more difficult to get into a slide.

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I’d love to keep reading about this. Can you suggest me some reading that support your views? I can go get some books from the university library or ask some friends who are still at university to get me the articles if you can point me in the right direction.

Also what the hell does angle of attack have to do with friction between two solid surfaces? 🤨

While polyurethane is semi crystalline equating polyurethane wheels to air filled rubber tires seems pretty crazy to me. Also saying that liquid and air act very much the same under pressure leads me to believe you don’t have a very strong grasp of physics. Gases are compressible while liquids are essentially not. That’s quite a difference. 😮

I’ve ridden hard and soft wheels plenty. Do tell me how riding them can make me assess the impact deformation has on grip in skateboard wheels cuz it isn’t exactly evident to me.

It seems to be that you’re just throwing out semi-related fancy terms at me and saying “it is how I say it is because I said so” without actually backing it up in any way.

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I would really like to make a study on skate wheel width and friction. I have a feeling the relationship between width and friction isn't linear because as the wheel gets wider, more area is outside of where the bearing is pressing down and it introduces a bunch of variables. Also, there is probably a different relationship for softer, tackier wheels because adhesion works differently.

Bearing make wheel go fast

[Sativa Lung]

A freshie I picked up to try a different wheelbase/length.

Is that toy PS Stix? I saw one on ebay and it looked like it had a different sticker (maybe bbs) and no laser engraved serial number

[nosneb]

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Girl Mike Carroll
PSSTIX OG mold/shape 1998
7.5x31.5 14inwb
Jessup
Bronze Allen key
Venture 5.25 low lite
Boardycakes 44mm wheels
Bones Bigballs

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Somehow it didn't register with me that this is PS Stix until watching that Griffin Gass clip Crail just posted. That's fucking rad.

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Best shape and concave it makes flip tricks are so effortless

[Nth syd bear]

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Girl Mike Carroll
PSSTIX OG mold/shape 1998
7.5x31.5 14inwb
Jessup
Bronze Allen key
Venture 5.25 low lite
Boardycakes 44mm wheels
Bones Bigballs

[close]

Somehow it didn't register with me that this is PS Stix until watching that Griffin Gass clip Crail just posted. That's fucking rad.

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Best shape and concave it makes flip tricks are so effortless

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Venture 5.0's and 50mm white 99a wheels would of been exactly what I would of skated on that deck in 98

It's cool to see someone skating these I assume  ur the dude that skated all those jovontae 7.5's??

[Kombuch-A-Holic]

Just set my MC up. And come to see this^^ Nice!!

8.0 it’s actually a little under and the black top ply doesn’t help me visually. I’ve been skating an 8.5 (Quincy wood/ love it) recently and this feels like a twig to me. Can’t imagine the 7.5!!

129 Forged hallow indys. Had to switch the bushings to the hards.
50mm classic formula fours.
Mob grip.

And some freshly laced Kalis S.

Everything is way too fresh. Lol

[ohthembones]

- AWS Triad Series/Frankie Spears • 8" 14.25"WB w/MOB
- Tensor Magnesium Lights (New Geometry) • 5.5's (8.125") w/Stock Pivots / Stock Bushings
- Ricta Chrome Cloud Wheels • 78A • 54mm w/Bones Swiss

The Tensors have a great turn! It's a little tighter of a turn radius than Indy but you get into the turn quicker sort of like with Thunders. They're the same height as Thunders w/Forged baseplates and a 1/8" riser. I left the kingpin nuts flush with the top of the kingpin to start out with. I weigh 76KG (168LBS) and even with keeping them loose I only got one slight hit of wheel bite on a very deep and quick u-turn before the bushings started breaking-in. The bushings took about an hour to break-in, prior to that they had that same sort of squishy sound Ace bushings make but no loud squeaks. I initially put a new set of Riptide Pivots in but with the finish on these trucks it actually made them much louder. I put the stock back in and they got quiet with no pivot squeaking as of yet. I cruised around for a couple hours this morning and really liked what I felt. I wanted to go with ultra-soft cruising wheels at first to get a sense of how they turn and what's going to make noise. The adjustment period for just riding around didn't take me long at all coming from Thunders. I popped a few Ollies up curbs and it sort of reminded me of Indy but not quite, hard to explain. Somewhere between Indy and Thunder regarding pop, at least on this board. I plan to switch out the wheels and give it a go at the park or some street spots to see how they grind later this week. So far I'm impressed and I cannot believe how light they are!

I also love the Alien 8" decks lately! Similar to a DLX Full shape but without the longer wheelbase. Works really well with 8" to 8.25" trucks.

Shoes: Nike SB Janoski's

[bbk]

5.5 is 8.25 on the new ones.

[ohthembones]

5.5 is 8.25 on the new ones.

I didn't know that. Thank you for correcting me! When I tried to look it up before buying them the Tensor/Thank You Supply site was down so I got the info from the SkateWarehouse site which said they were 8.125". I didn't see any difference between them and my Thunder 148's so I figured it was such a small difference I wouldn't notice it by eye.

[UPPERCASEnocap]

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A freshie I picked up to try a different wheelbase/length.

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Is that toy PS Stix? I saw one on ebay and it looked like it had a different sticker (maybe bbs) and no laser engraved serial number

Unfortunately, I don't believe it is either. I got juiced when i saw the graphic at my local and wanted to try this deck/graphic for a minute. Couldn't pass it up even tho its a pricepoint which I believe is Dailan Huahong. I flipped it over and the sticker reads "made in China". Definite bummer but she still skates rad!

[Xen]

Magenta Vivien Feil 8.4
Film trucks 6.0
Pusher Bearing Ceramics
Taste Wheels 53mm full conical
Ashes griptape
some hardware

'Haslam missed opportunity'

[rocklobster]

Decided to skate the stuff I already had instead of getting a new board, plus I wanted to do a smaller, more technical board to practice for slides on a lower ledge.

Traffic Bobby Puleo - 7.75 x 31.3 x 14
Thunder 147 Lights
Spitfire Classics 52mm
Spare bolts and bearings I had lying around.

Wasn't too happy with the griptape setup, the file on the back of the Silver skate tool is too smooth to get a nice groove onto the board. Plus I snapped the axle nut part of the tool trying to tighten the nuts on the board.

Coming form a 8.06, the 7.75 felt tiny. The kicks and board was pretty mellow, coupled with the short wheelbase resulted in not a lot of pop off my kickflips, even when using the nose to pop. The axle to axle wheelbase was around 17.19 which was pretty short.

The lowered height did make grinds and slides much easier to lock into since I wasn't trying to stomp my tricks onto the ledge.

Think I fucked my right knee up when doing a BS 50-50, board got away from my and end up doing a split with my knee going slightly sideways.

I'm really pleased with Spitfire Classics, even though they aren't Formula 4 they had a much better grip on Skatelite than the F1 Streetburners I was rocking.

Definitely sticking to a 8.0 from now on, can't believe I used to ride 7.5 boards for so long.

Now, I thinking if I should try Venture 5.2 (Lo or Hi).

[DirtyBurger]

- AWS Triad Series/Frankie Spears • 8" 14.25"WB w/MOB
- Tensor Magnesium Lights (New Geometry) • 5.5's (8.125") w/Stock Pivots / Stock Bushings
- Ricta Chrome Cloud Wheels • 78A • 54mm w/Bones Swiss

The Tensors have a great turn! It's a little tighter of a turn radius than Indy but you get into the turn quicker sort of like with Thunders. They're the same height as Thunders w/Forged baseplates and a 1/8" riser. I left the kingpin nuts flush with the top of the kingpin to start out with. I weigh 76KG (168LBS) and even with keeping them loose I only got one slight hit of wheel bite on a very deep and quick u-turn before the bushings started breaking-in. The bushings took about an hour to break-in, prior to that they had that same sort of squishy sound Ace bushings make but no loud squeaks. I initially put a new set of Riptide Pivots in but with the finish on these trucks it actually made them much louder. I put the stock back in and they got quiet with no pivot squeaking as of yet. I cruised around for a couple hours this morning and really liked what I felt. I wanted to go with ultra-soft cruising wheels at first to get a sense of how they turn and what's going to make noise. The adjustment period for just riding around didn't take me long at all coming from Thunders. I popped a few Ollies up curbs and it sort of reminded me of Indy but not quite, hard to explain. Somewhere between Indy and Thunder regarding pop, at least on this board. I plan to switch out the wheels and give it a go at the park or some street spots to see how they grind later this week. So far I'm impressed and I cannot believe how light they are!

I also love the Alien 8" decks lately! Similar to a DLX Full shape but without the longer wheelbase. Works really well with 8" to 8.25" trucks.

Shoes: Nike SB Janoski's

The newness of everything here reminds me of a tech deck. Sick setup, and I'm kind of interested in trying some Tensors now.