Design for over or under steer?

[raymondu999]

That mclaren car is mis leasding though, I think it's sprung so stiffly that you will see front wheel locking since wheels have different loading but the same braking pressure.

All cars have weight transfer, and will lock when you brake too hard. Point is - 2 tyres at threshold braking is better than 1 tyre locked and 1 at threshold, because the weight transfer is not so much that the threshold of the loaded tyre is over twice that of the unloaded inside tyre.

[flynfrog]

That mclaren car is mis leasding though, I think it's sprung so stiffly that you will see front wheel locking since wheels have different loading but the same braking pressure. At one race, i can't remember which one, USA? Button was locking almost every turn, and his style is quite different.

not sure how you attribute that to a stiff car? Or how you have any way of telling its any more stiff than any other f1 car.

[PlatinumZealot]

Trail braking you will always have one wheel with less grip because the car is in yaw and roll.

[astracrazy]

in 2007 and 2008 we used to see this a lot. in 2009 too but this was more a rear wheel and for different reasons lol

[ringo]

That mclaren car is mis leasding though, I think it's sprung so stiffly that you will see front wheel locking since wheels have different loading but the same braking pressure. At one race, i can't remember which one, USA? Button was locking almost every turn, and his style is quite different.

not sure how you attribute that to a stiff car? Or how you have any way of telling its any more stiff than any other f1 car.

Just have to watch the videos closely, easy to see which car's are sprung more stiffly by looking on relative suspension movement. Mclaren have generally been sprung stiffer than most.
As for 2 tyres at threshhold braking, no driver is going to achieve that every corner if at all, the wheels don't undergo perfectly equal loading.
And there is no way to see a car at "threshold braking" from watching a video. If there is no visual signs of grip limit, how do we know if the car is braking at the threshold?
Locking the inside is probably more indicative of going slightly over limit on the inner wheel on teetering on the limits of the outer.
Which can probably be a good compromise on late braking or trail braking, if locking is not excessive. slight smoke i don't see as an issue if due to the nature of the setup, loads or track surface, a little locking in a few corners may occur.

[flynfrog]

You can tell spring rates on cars with tons of df and less than a few inches of travel by watching tv? How do you know its just not over dampened?

[ringo]

As for tonnes of downforce, the differences aren't so high. A tonne of downforce is a lot.
The cars were very close last year, and to keep the discussion simple, i guess you can safely assume that in qualifying, on basically the same fuel, if a redbull is braking at basically the same distance as a mclaren and a ferarri and they all have the same tyres then it cannot be unsafe to say the have similar downforce levels (not a tonne difference) . And if the one with higher df and the one with less df seem to have more suspension travel visually then where does that put the car that's in the middle in terms of df that has less travel? I may be wrong but i can guess the one in the middle is sprung stiffer.

As for damping, that's harder to see from on board. In fact to be honest i can't see that.

If we go back to wheel blocking, there are some really good slo mo videos out there.
Hamilton does block them more than often. Though we've been seeing a lot from Button in 2012.
I'm not sure if it's a case where the pirelli performance degrades so much that one lap you feel you know how hard to brake to get the max from the tyres in a certain corner, then the next time around, with a more degraded tyre and maybe a few degrees more or less of track temperature, you try the same pressure on the brakes and you are looking at a different tyre altogether.

[flynfrog]

As for tonnes of downforce, the differences aren't so high. A tonne of downforce is a lot.
The cars were very close last year, and to keep the discussion simple, i guess you can safely assume that in qualifying, on basically the same fuel, if a redbull is braking at basically the same distance as a mclaren and a ferarri and they all have the same tyres then it cannot be unsafe to say the have similar downforce levels (not a tonne difference) . And if the one with higher df and the one with less df seem to have more suspension travel visually then where does that put the car that's in the middle in terms of df that has less travel? I may be wrong but i can guess the one in the middle is sprung stiffer.

As for damping, that's harder to see from on board. In fact to be honest i can't see that.

And you know the downforce levels between cars how? You are basically piling assumptions on top of one another to get the result you want.

[ringo]

Well an F1 car doesn't have as much downforce as a Lemans car (well i don't know about the current ones). Simply doesn't have enough surface area.
There are threads on that discussion already by the way. 640kg is not a lot of mass to manage for a car, and it flatters the downforce a lot.
A lot of high numbers have been bandied about for an F1 car, and the truth is those figures aren't seen at all, and if they are, they are theoretical for max downforce setting, at a maximum speed, probably at a higher speed than the drag limit for the car at that max setting itself and will not be experienced in reality. The journalist will take these and report them.

Don't be surprised if a front wing only has 800lbs of downforce at 150mph, which is less than half a tonne. People tend to go overboard with their estimates.
A good excercise is if you know the deceleration G force and a few other parameters to do a calculation.
Truth is, there is no way a car is going to have 2200 pounds more downforce than another car that is sitting next to it on the grid that is only 2 tenths slower power lap; all cars being on the same tyres. That would be a different class of car to itself.

[rifrafs2kees]

That mclaren car is mis leasding though, I think it's sprung so stiffly that you will see front wheel locking since wheels have different loading but the same braking pressure.

All cars have weight transfer, and will lock when you brake too hard. Point is - 2 tires at threshold braking is better than 1 tyre locked and 1 at threshold, because the weight transfer is not so much that the threshold of the loaded tyre is over twice that of the unloaded inside tyre.

I beg to differ. For one the only way one can achieve threshold braking on both tires in a turn would be through variable brake pressure between the left and right sides. With that not allowed, we assume that the braking pressure is even. Unless we know the nature of the turn, we cannot determine whether or not sacrificing the braking force of the unloaded tire outweighs the benefit of having the loaded tire at threshold braking. The higher the load transfer the less important it becomes to avoid a lock up of the inside wheel. If the turn is sharp enough, and the downforce isn't there then I can imagine load transfer being extreme to sometimes make the inside locking beneficial over a lap...not so over an entire race.

[raymondu999]

I apologise. I meant "combined threshold" as opposed to both being at individual threshold. ie braking just below the limit of the unloaded tyre.

[flynfrog]

Well an F1 car doesn't have as much downforce as a Lemans car (well i don't know about the current ones). Simply doesn't have enough surface area.
There are threads on that discussion already by the way. 640kg is not a lot of mass to manage for a car, and it flatters the downforce a lot.
A lot of high numbers have been bandied about for an F1 car, and the truth is those figures aren't seen at all, and if they are, they are theoretical for max downforce setting, at a maximum speed, probably at a higher speed than the drag limit for the car at that max setting itself and will not be experienced in reality. The journalist will take these and report them.

Don't be surprised if a front wing only has 800lbs of downforce at 150mph, which is less than half a tonne. People tend to go overboard with their estimates.
A good excercise is if you know the deceleration G force and a few other parameters to do a calculation.
Truth is, there is no way a car is going to have 2200 pounds more downforce than another car that is sitting next to it on the grid that is only 2 tenths slower power lap; all cars being on the same tyres. That would be a different class of car to itself.

I don't believe I ever said there was a large difference between cars I said you cant tell by watching TV.

[ringo]

ok,
Well i think rifrafs2keys made a good post. Couldn't have said it better myself.

[jamsbong]

This tire lock-up issue is not as bad as it looks if the inner front tire locks up. Because that is the unloaded tire. The flat spot will be minimal. If the outer front tire locks up, then you'll end up with a bumpy ride.

Speaking of driving. I saw this clip today:
http://en.espnf1.com/ferrari/motorsport ... 98943.html

Like a champ, Alonso also wins the ice-karting event held at the Wroom festival.
Notice that he chose to brake early to make a tight turn. That way he could power-down and countersteer out of the corner while other driver just understeer and have to slow down on exit.

[Coefficient]

Moved from MP4-28 thread ....

Hamilton like Oversteer!! Button is from the Coutlhard shool of thought and prefers balance. He hates oversteer and prefers a neutral car but can deal with understeer.