This is a small quote extracted from a feature at f1.com website. These are words from Hirohide Hamashima, Bridgestone’s Director of Motorsport Tyre Development:

Quote :

“We issue a safe range of pressures for our tyres and the teams must keep within this range, but there is still good scope for drivers to dial-in to get their preferred response. In basic terms a higher pressure within the safe limits we give will provide more stability, whilst a lower pressure means the tyre heats up slower, but it also degrades less, and is less sensitive to bumps.”

In some ways the behaviour we have in LFS is the opposite to what thery're saying here. What do you think?

You can read the whole article here:
http://www.formula1.com/news/features/2008/7/8164.html

I think bridgestones squirm a lot and give poor feel, and un-even wear.

Low pressure = heat will kick-in quickly, and you will get the best response at the end... i think that's what he means

Quote from chanoman315 :

Low pressure = heat will kick-in quickly, and you will get the best response at the end... i think that's what he means

If that's what he meant I understood it totally the opposite way

Same lol. So, who's the nub. LFS or the Bridgestone director thingy? :P

+1. I am pretty sure he was either mis quoted or mistaken.

I'm pretty sure that the way LFS tyres heat and cool is not 100% correct along with limited contact patch modeling, which then gives unrealistic grip at extremes (i.e. too lower pressure irl would lead to tyre contact patch distortions and tyre damage thus reducing grip considerably).

In F1 there is more variables to consider as changing the tyre pressure has a significant impact on the overal suspension frequency response the car has, compared to say changing the tyre pressurse in a road car.

Tyres irl get heat from several means (friction, tyre deformation, radiated heat from brakes, etc) and although LFS mimics this I don't necessarily believe it is in the correct ratio in all circustances. I have read also several times (from reputable sources) that higher pressures can give more grip. It all depends on the surface conditions, weather conditions and more importantly the rubber compounds used.

If for example the rubber is very soft then perhaps a large amount of the grip and heat is being generated by friction, it would then make sense that in an F1 car higher pressures would generate more heat as it would make the whole car stiffer and increase the effect of tyre friction.

My suspision is F1 tyres rely more heavily on grip generated by friction than you would expect the case to be in a road car.

Er... where do you expect grip to come from, other than friction?

2 things.

Normally lower tryre pressure means the rubber flexes more easily and so generates more heat.

However, IF higher tyre pressures give less grip, they will slide more and generate more heat.

So who knows??

Quote from Crashgate3 :

Er... where do you expect grip to come from, other than friction?

Tyre grip comes from two main sources both combine to the give total grip of the tyre.

One is friction (the grip you have when a tyre is spinning comes purely from friction) the other is mechanical grip (this is the effect of the rubber being pressed against the road taking the shape of the tarmac and thus giving a mechanical "grip")

The amount of grip a tyre gives from mechanical and friction is determined by surface type, temperature and compound of the tyre. The way a tyre heats and cools will also be partly determined by the above factors.

Quote from Glenn67 :

One is friction (the grip you have when a tyre is spinning comes purely from friction) the other is mechanical grip (this is the effect of the rubber being pressed against the road taking the shape of the tarmac and thus giving a mechanical "grip")

You do realise that what you are describing is friction and friction, right?

Imagine putting ur hand against a door to shut it, thats mechanical. Whereas firction would be to put your hand against the side of the door to shut it.

|- = Mechanical
|| = Friction

And what's that example of leverage on doors have to do with the difference between static friction (which Glenn67 termed "mechanical grip") versus dynamic friction, which is what both you (Benji) and Glenn67 simply dub "friction"?

There is nothing exotic (or flamboyant like "mechanical grip" or "esoteric spiritual roadbinding") behind the grip of a tyre on tarmac - or any surface for that matter. It's all just friction and ways of optimizing it (see: suspension, tyre width, rubber compounds, downforce etc).

Grip is the result of friction between the tyre and road.

The two different principles that effect friction with regards to tyres are adhesion and deformation.

Adhesion is the chemichal bond between the tyre compound and the road surface.

Deformation is how the tyre compound changes shape to follow irregularities in the surface. The more the tyre deforms around the surface the greater the surface area or contact patch. This means that there is a greater contact patch for adhesion to occur.

bridgestone should try making tyres out of geckofeet to take advantage of van der waals forces... hows that for flamboyant?

Quote from Shotglass :

bridgestone should try making tyres out of geckofeet to take advantage of van der waals forces... hows that for flamboyant?

In one move you just solved the downforce-is-bad-for-overtaking problem and also gave everyday people a way to run their normal everyday cars upside down in tunnels.

Check this out aswell:

"AIR PRESSURE
The amount of air in the tyres. Changing air pressure in the tyres is used as setup tool. Higher air pressure will create temperature in the tyres faster than a lower tyre pressure."

http://www.v8x.com.au/cms/A_101914/article.html

It's the same in karting the hotter the weather the lower the pressures you run. My way of understanding it the more pressure in the tyre means it can slide along the road and generate more friction as a result. I always thought it worked the other way round until I was told otherwise...

In karting low pressure = low temp = less grip until it heats

high pressure = fast heat = fast grip but soon excess of temp = less grip & more degrade

I think the part of the quote being overlooked in this discussion is

Quote :

within the safe limits

.
I took that as "we are talking about a small window of pressures", so I assume they aren't talking about letting the pressure so low as to run hot like you can in LFS. Tyres have been seen to rip themselves apart from stress as it is so I'd imagine the window to be maybe only a couple of PSI or so.

This is such an interesting debate which is currently going on in the team i am involved in.

On the one side, we have an ex karter (world rotax max champion) who believes the following: High pressure= higher volume of air molecules, therefore more molecules banging into each other, therefore more friction... and therefore, more immediate temperature throught the tyre. All this means the tyre comes on more quickly, but may not last as long.

The other arguement in the team is from a single seater race engineer who says: Lower pressures mean more "roll"/"flex" which creates more friction in side walls etc. This allows the tyre to generate heat quickly and therefore, comes on quickly. Higher pressures allow less roll/flex and therefore, slightly longer to come in but more stability (pronlonged life).

The reply from the karter... Softer temps generates side wall heat and mainly surface temperature which is not what cause a tyre to work, as you need core tyre temp to work, not only surface heat.

Who the hell knows?

Quote from xaotik :

In one move you just solved the downforce-is-bad-for-overtaking problem and also gave everyday people a way to run their normal everyday cars upside down in tunnels.

when i thyped it i did actually consider not typing it and saving the idea to see if i can get a patent out of it... its quite clever... if it works at 300kmh

just imagine how it coule revolutionize parking and instantly double the amount of parking spots an any parking garage

Quote from Shotglass :

just imagine how it coule revolutionize parking and instantly double the amount of parking spots an any parking garage

Not to mention the all-new obstacle courses that the marines would have to go through.

thats another thing... it will change urban combat from ugly to comedy gold... all you have to do is place a few small remote controlled explosives on the wheels of hanging cars and wait

I don't know why this is for sure, but from practical experience in standard cars and from spending time in the paddock with race cars, typically, high pressure=a hotter tire in a shorter time. Lower pressures=a tire that takes longer to heat up and get "to pressure and temperature".

For qualifying and short stints, tire pressures are typically higher than you would set for a long stint. For hot days, tire pressures are generally lower than you would set for cool days.

LFS seems to have it backwards in practice. We always go out with low pressure for qualifying and hot laps and use high pressure for long stints. We get more grip from lower pressures, but suffer from over heated tires in a hurry. If we exclude major tire spin or sliding, then this seems a bit backwards.


Real tires have an optimum temperature and pressure where they work best. This will also be dependent on the car, the suspension type and track type. In LFS, this optimal setting seems a bit hard to come by.

Could it be that there is a lot of heat transfer going on between the tire surface and the air in the tires? At low pressures, the air inside the tire can take a lot of heat because it has the room to expand? Once to pressure, the air can't take much if any more heat from the tire so there is no more "heat sink" to use?