Mercedes AMG F1 W06

[Moose]

I'm pretty sure tire pressure doesn't change when it's "squeezed." In a closed system, pressure is the result of temperature and volume.

Squeezing something reduces its volume.

A circle is the shape with the single highest circumference to area ratio. If you flatten it, or add indentations in it, the area (and hence the volume of an extruded cylinder) reduces.

[bhall II]

Not in a closed system. Think about it.

You can't change the volume of air in a tire unless you add or remove air.

[Moose]

Not in a closed system. Think about it.

You can't change the volume of air in a tire unless you add or remove air.

Of course you can - by changing the pressure of that air. What you can't change is its mass.

The circumference of the tire doesn't change (at least not significantly), but the shape does. Therefore the volume changes. Therefore the pressure changes.

That's why the tire bounces when you drop it - because it transfers kinetic energy into potential energy as pressure, and then releases that energy again to bounce back up.

[bhall II]

Are we talking about pressure on the contact patch or about pressure within the tire? I can understand your point of view in the case of the former, but not the latter.

[bill shoe]

I was a tire evaluator at a proving ground for a few years where I tested hundreds of sets of prototype tires. I would usually start checking tire pressures when the car was still up on the lift, and then finish checking (or repeat initial checks) once the car was on the ground. The pressure would typically go up around half a psi in the tires when the car was set down on the ground, this was with very accurate analog dial gauges.

The above is due to the static weight of the vehicle. I would assume additional normal force on the tire due to downforce would increase the effect further.

I think additional normal force due to the initial hit on a curb would also have the same effect. This curb force would not be a steady-state thing, just an inertial thing for a split second, but it would still be additional normal force on the tire which would still result in a corresponding pressure increase.

[Moose]

Are we talking about pressure on the contact patch or about pressure within the tire? I can understand your point of view in the case of the former, but not the latter.

The latter. What makes you think that the same mass of air contained in a smaller volume will not have a higher pressure?

Or conversely, if you apply pressure to a constant mass of air, the volume won't shrink?

[bhall II]

What makes you think that the same mass of air contained in a smaller volume will not have a higher pressure?

I don't. I just don't see how volume will change drastically unless the tire is underinflated/overloaded, otherwise the rubber will accommodate...

[hollus]

I am probably out of my breadth here, apologies if this is totally wrong; but can it be that the hollow rim acts like an additional hydraulic spring/damper combination?
I am assuming that the rims are hollow all the way to the end, in that case their volume could be, say, 5% of the total tire volume. That's small but it is in a separate chamber. Sure it is connected to the main chamber, but the connections are relatively small holes and the path to fill the chamber tortuous with 90 degree bends and narrow passages. (The damper analogy is probably a terrible one, I'd imagine the energy dissipation through the tortuous path to be very small compared to the heavy deformable rubber that is the tire itself).
While the inside of the tire is a well interconnected chamber, where circulation is free and pressure equalization must be quite fast, the air might take 1/100th or 2/100th of a second to do so in the rim chamber.
Could this act like a small hydraulic spring in series to the hydraulic spring that the tire naturally is? Would it matter? The pressures would be similar at all times, so do two similar springs in series behave differently to a larger spring?
In any case it appears to me that by the mere delay of air (and pressure waves) flowing in and out of this chamber, this could help reduce pressure spikes in the tire (both high and low) and also that it would help break down any possible resonances; as if the tire is resonating, the rim will be off phase by its small delay (would its smaller volume also change the frequency?).

[DiogoBrand]

I'm pretty sure tire pressure doesn't change when it's "squeezed." In a closed system, pressure is the result of temperature and volume.

It's simple: Pressure is the result of weight, temperature and volume. When the tyres are "squeezed" because of mechanical or aerodynamical load, rolling, pitch, or whatever, the volume decreases while weight and temperature stay the same and therefore, although not very much, pressure rises.

[RichardF1]

https://twitter.com/SkySportsF1/status/ ... 5636452352 Special Spa Wing for Mercedes, the return of the spoon wing a-la Sauber 2014. Notable differences, obviously the profile! revised gills and a slit on the endplate, along with a revised endplate profile (notice the bulge at the epsom logo), and a monkey seat (if you can call it that!)

[tranquility2k4]

It has been reported that Merc have a new front wing here, anyone spotted it? I'm guessing it's a lower downforce FW.

[mclaren_mircea]

Did they used the new rear wing in Free Practice one?

[OO7]

It has been reported that Merc have a new front wing here, anyone spotted it? I'm guessing it's a lower downforce FW.

My understanding is that there is a slight change to the small deflector on the outside of the end-plate, so not really a new front wing, just a subtle alteration.

[Owen.C93]

Regarding the tyre pressure change. Simply put a tyre carcass can compress much more easily than it can expand. So when you rest it on the floor the lower side will go flat and compress, but the upper will only expand very slightly to compensate. So the air must compress slightly. In shock loads of curbs this is more evident.

[CBeck113]

I'm pretty sure tire pressure doesn't change when it's "squeezed." In a closed system, pressure is the result of temperature and volume.

It's simple: Pressure is the result of weight, temperature and volume. When the tyres are "squeezed" because of mechanical or aerodynamical load, rolling, pitch, or whatever, the volume decreases while weight and temperature stay the same and therefore, although not very much, pressure rises.

What you're saying is that the form of the tire is rigid everywhere on the tire except on the contact patch, which is not true - the question is how much of a pressure change is necessaary to change the form (i.e. increase the volume) of the tire in regards to the fact that it is a flexible material.