Red Bull RB7 Renault

[mep]

Right so the tyre generates cornering force because it slips, right?

Not really.
The term slip is a bit misleading in this context because it is more related to the deformation of the rubber than sliding movement of the rubber on the tarmac.
The contact area stays still on the tarmac for an instance while the wheel is turning but the rubber deforms in relation to the rim. By this you get some difference in wheel rotations and travelled longitudinal distance when you think of acceleration. This means for a given wheel rotation and a given wheel diameter your car travels a slightly smaller distance than calculated with a complete stiff tire.
Or when you think of cornering you get a difference between the direction your rim points and the actuall movement. Important is to understand that this does not mean there is slip (sliding) between the rubber and the tarmac you still have static friction coefficient. Think of the chains of a tank.

Now, the more downforce you apply to the tyre, the more cornering force it will generate for a given amount of slip.

The slip value can be seen as something like deformation. For a given lateral force you will have a given deformation unless you change the stiffness of the tire. So more downforce -> more cornering force -> higher deformation/slip angle.
What you do have is a drop of friction coefficient when you put more load on the tire.

Some years ago I put a quite good explanation of it on this forum. Maybe I search for it later.

Slip = wear due to friction, sort of rubbing an eraserover a piece of paper.

No. See above.

[SiLo]

So essentially we are saying that the tyre can only generate so much lateral grip, and that Red Bull are right on the limit for it?

So when they go through a corner the trye is giving up as much grip as possible, before the rubber literally comes away from itself because of the shear force.

This all makes sense, but I don't think it's the full story, most likely an amalgamation of tyres, df and engine mapping. However, the Mclaren was easily the better race car on Sunday in Spain, maybe as they add DF, their inherent balance makes the car more driveable than the slightly twitchy Red Bull (in comparison).

[mep]

No
More downforce = more grip => better driving characteristics.
There is no reason to go for less downforce because of the tires.
How do you even come up with such ideas?

[PhillipM]

The term slip is a bit misleading in this context because it is more related to the deformation of the rubber than sliding movement of the rubber on the tarmac.

Well, not really, because the surface of the rubber IS creeping sideways across the tarmac in order to generate grip...

[marcush.]

the more the better ? sure not
If you look at a vertical load vs grip diagramme it is not a linear relationship but there is a law of dimishing returns..So for each N of vertical force the added performance in terms of grip gets less and less until you reach a point where the gains in grip are just not measurable.

In this it does not really matter if the vertical force in downforce or sheer weight .the tyre gets saturated and adding more vertical force will not increase grip.

So there is a fine line to draw in terms of adding downforce and drag considerations will stop you from just adding more and more even if it was possible to add vertical force by cranking on more wing.

So like every engineering exercise it´s a well balanced compromise you are looking for with a lot of variables not all under your control...(ambient temp ,track temp as obvious examples,grip levels supplied by the track etc etc)

[timd]

The way i read into it is that in spain Mclaren were more effecient with their tyres over the race because they ran with less downforce but also some less drag.

They made up some time on teh straights and this takes nothing out of the tyres.

Vettel was faster in the high speed corners which sucked the life out of them more and then carried the drag down the staights.

The Redbull was asking more of these tyres with very finite life and that is an issue.

You couild say Vettel should have not pushed so hard in the high speed but he will still be carrying the drag on the straights and would have gone slower.

When you look at it like this then i would say yes because of the nature of the tyres redbull put on too much downforce.

With the nature of these cars now and the symbyotic nature of how interactive all the air flows are is it really that easy to add and remove downforce? I dont know.

[horse]

The term slip is a bit misleading in this context because it is more related to the deformation of the rubber than sliding movement of the rubber on the tarmac.

Some years ago I put a quite good explanation of it on this forum. Maybe I search for it later.

OK, thanks for the info. Here is the Wikipedia page for Slip angle. Pretty much says what you said.

I think my logic still holds though, saying that more DF requires less slip angle over the lap than a car with less DF, then the degradation on the tire should be less - presumably from the tyre not having to deform as greatly.

We have surely lost the topic now.

[marcush.]

The way i read into it is that in spain Mclaren were more effecient with their tyres over the race because they ran with less downforce but also some less drag.

They made up some time on teh straights and this takes nothing out of the tyres.

Vettel was faster in the high speed corners which sucked the life out of them more and then carried the drag down the staights.

The Redbull was asking more of these tyres with very finite life and that is an issue.

You couild say Vettel should have not pushed so hard in the high speed but he will still be carrying the drag on the straights and would have gone slower.

When you look at it like this then i would say yes because of the nature of the tyres redbull put on too much downforce.

With the nature of these cars now and the symbyotic nature of how interactive all the air flows are is it really that easy to add and remove downforce? I dont know.

Does RB have tyre degradation issues? not really methinks .Even though the line of argumentation has a point .
To me the difference is mainly in RedBull being able to exploit the tyre s potential in Qualy better due to their two setup approach using the lower drag /downforce for the quicker corners and using the tyres to the max in Qualy ...but with added mass with full tanks is just hurting them more than Mclaren who might have a few Newtons less downforce =less vertical load that robs them of tyre grip.additionally RB has only the high downforce configuration for the race something they are not using in practise and qualy..adding more vertical load.saturating the tyres even more.

[timd]

It might even be a problem redbull are having made worse by a damper issue due to these new super hards being new. Bit of super hard rig work needed?

Like you say its harsh to call it a "problem". Just minor diferences between teams. A small percentile here or there.

I do agree that redbull's qualy form is a combination effect and with DRS is where their higher DF config really shines. I also think if and when the off throttle fuel flow is stopped they will loose slightly more than others.

[hardingfv32]

"redbull's qualy form is a combination effect and with DRS is where their higher DF config really shines"

They are also equal to the best at the start of the race.

I believe the rear wing is restricted to a box with a max height of 220 mm. If the DRS opens a 50 mm slot then the wing has lost 25% of its operating surface. I know there could still be some interaction between elements when the DRS is open, but could we state that downforce is reduced 25%?

For discussion say the front and rear wing each contribute 40% of the downforce, a 25% reduction at the rear during much of qualifying would seem very impressive imbalance from race condition. I am assuming that they DRS is being used much more than the other teams during qualifying and not at all during the race.

Brian

[Owen.C93]

"redbull's qualy form is a combination effect and with DRS is where their higher DF config really shines"

They are also equal to the best at the start of the race.

I believe the rear wing is restricted to a box with a max height of 220 mm. If the DRS opens a 50 mm slot then the wing has lost 25% of its operating surface. I know there could still be some interaction between elements when the DRS is open, but could we state that downforce is reduced 25%?

For discussion say the front and rear wing each contribute 40% of the downforce, a 25% reduction at the rear during much of qualifying would seem very impressive imbalance from race condition. I am assuming that they DRS is being used much more than the other teams during qualifying and not at all during the race.

Brian

Lewis Hamilton said it was a 30 point reduction in downforce. And that gave a good representaton of the difference between RB and McLaren since Vettel cold take the final corner at Barcelona with DRS open and Lewis found it just as hard with his closed.

[Raptor22]

Right so the tyre generates cornering force because it slips, right?

Not really.
The term slip is a bit misleading in this context because it is more related to the deformation of the rubber than sliding movement of the rubber on the tarmac.
The contact area stays still on the tarmac for an instance while the wheel is turning but the rubber deforms in relation to the rim. By this you get some difference in wheel rotations and travelled longitudinal distance when you think of acceleration. This means for a given wheel rotation and a given wheel diameter your car travels a slightly smaller distance than calculated with a complete stiff tire.
Or when you think of cornering you get a difference between the direction your rim points and the actuall movement. Important is to understand that this does not mean there is slip (sliding) between the rubber and the tarmac you still have static friction coefficient. Think of the chains of a tank.

Now, the more downforce you apply to the tyre, the more cornering force it will generate for a given amount of slip.

The slip value can be seen as something like deformation. For a given lateral force you will have a given deformation unless you change the stiffness of the tire. So more downforce -> more cornering force -> higher deformation/slip angle.
What you do have is a drop of friction coefficient when you put more load on the tire.

Some years ago I put a quite good explanation of it on this forum. Maybe I search for it later.

Slip = wear due to friction, sort of rubbing an eraserover a piece of paper.

No. See above.

I am not talking about slip angle, I am talking about shear and sliding at the tyre contact patch.
The adhesive forces between tyre and tarmac is great and under the correct conditions is greater than than the adhesive forces holding the tread together.

[ringo]

What i think is before we get into the hyper detail, we don't really know what the limit of the pirelli tyre is.
These tyres were used on 2010 cars which had more downforce than the current F1 cars.

Also i don't see why loading the tyre more would increase wear.
There are two things to look at, wear and degredation and it's dificult to pinpoint the relationship between downforce and any of the 2 with the pirelli hard tyre specifically.

Going off the evidence, Vettel could have done 3 stops in turkey and win the race, and Webber did 4 but had more life in his than Alonso's car which is good on the soft and hards.

I don't know what's really happening but The redbull always seemed to care the tyres better, so Horner's vague beat around the bush explanation is a distraction.

I guess they tyre experts can make sense of this, but i doubt they could say anything specific to the mysterious pirellis. For even Ferrari can't understand the new hard tyre.

[hardingfv32]

"There are three primary factors; tire force level, pavement texture and tire surface temperature. The major factor of these three is the sustained or instantaneous tire force level. Accelerometer measurements show that cornering or lateral forces are chiefly responsible for wear in contrast to longitudinal (driving and braking) forces and the test system is designed to operate on the basis of such cornering forces. The wear rate depdnds on tire cornering force raised to an exponent."

ACCELERATED TIRE WEAR UNDER CONTROLLED CONDITIONS. 2. SOME FACTORS THAT INFLUENCE TIRE WEAR

Veith, A G, Goodrich (B F) Research and Development Center

I guess one could say the more downforce allows greater lateral cornering forces... and greater wear.

Brian

[speedsense]

What i think is before we get into the hyper detail, we don't really know what the limit of the pirelli tyre is.
These tyres were used on 2010 cars which had more downforce than the current F1 cars.

Also i don't see why loading the tyre more would increase wear.
There are two things to look at, wear and degredation and it's dificult to pinpoint the relationship between downforce and any of the 2 with the pirelli hard tyre specifically.

Going off the evidence, Vettel could have done 3 stops in turkey and win the race, and Webber did 4 but had more life in his than Alonso's car which is good on the soft and hards.

I don't know what's really happening but The redbull always seemed to care the tyres better, so Horner's vague beat around the bush explanation is a distraction.

I guess they tyre experts can make sense of this, but i doubt they could say anything specific to the mysterious pirellis. For even Ferrari can't understand the new hard tyre.

(first bolded) More load = more acquired Lateral G = more cornering MPH = more "work" for the tire = more wear. In short the contact patch is increased in size with load and the slip angle is slightly larger, thus increasing the size of the pneumatic trail (the sliding portion of the tire's trek back to it's original shape before contact with the ground) It is the pneumatic trail that causes the most amount of wear in a perfectly working tire as this portion of the tire is sliding across the ground.

(second bolded) Spain is the first time this year, that the RB7 has been tested under a full race condition and the car having to be pushed through out a race. A perfect example of the Mclaren's and RB's tire wear. Previous races have had conservation involved with the leaders and the others playing catch up. Big difference in tire wear. IMHO