Driver styles/preferences

[Jersey Tom]

Moving static mass distribution forward (aka more nose weight) will TEND to increase understeer.

But, few things are absolute. As for the other post with stability and yaw rate.. will tackle that later, after this pizza.

Edit - Think that author of the earlier snippet meant to say, a car with positive directional stability will return to zero yaw acceleration, which is what I had issue with. Rest is a bit of a simplification, but more or less accurate.

[godlameroso]

Allright. Briefly-

Very few things are a black and white '1' or '0'. Prefering understeer or oversteer, pointy or stable, active or passive, whatever. All of these are valid but they're all a sliding scale. When I order a steak I don't get asked if I want it 'cooked' or 'raw' - depending on the cut, thickness, and my mood I might like varying degrees of doneness.

With regard to karts... are we talking 85 mph top speed or mid corner speed? In any event, they're a unique animal given the super short wheelbase, no suspension, speeds and corner geometry. I don't know of any other major vehicle class where the goal is to lift an inside rear tire to get around a corner. Besides, going through a power-limited high speed corner you don't want the rear end to be sliding all over - it's straight up going to be slow, bleeding speed and abusing the tires.

Trust me. An appropriate dose of understeer at the right times is a good thing.

Front wheel drive sports cars(oxymoron I know) will tripod through medium and slow speed corners, at least mine does, but I set it up that way.

[raymondu999]

You mean the rear inside lifts? Or the front inside?

[marcush.]

Moving static mass distribution forward (aka more nose weight) will TEND to increase understeer.

But, few things are absolute. As for the other post with stability and yaw rate.. will tackle that later, after this pizza.

Edit - Think that author of the earlier snippet meant to say, a car with positive directional stability will return to zero yaw acceleration, which is what I had issue with. Rest is a bit of a simplification, but more or less accurate.

Few things are absolute ,thats the point.
shifting weight forward could yield more front grip in certain circumstances.

And for the three wheeling :wasn´t it all about maximising grip ?A wheel not on the ground cannot transmit grip so you are throwing away a quarter of your total grip available away deliberately..and optimise for the remaining 75%...you leave an awful lot on the plate ,mate.

[godlameroso]

Well for a FF car, most of the weight and center of gravity is towards the front, therefore grip at the rear is the enemy of yaw in these cars. Since no drive goes to the rear to make the tires slip, you set up stiff ARB's and extension damping to make the inside rear wheel lift to create the slip.

Also regarding moving ballast to the front, moving ballast forward will tend to generate understeer....to a point, the same with moving it to the rear. Porsche 911 comes with 40:60 weight distribution, and it understeers unless you're trying to heavy trail brake, especially models before the 996.

[Jersey Tom]

Well for a FF car, most of the weight and center of gravity is towards the front, therefore grip at the rear is the enemy of yaw in these cars. Since no drive goes to the rear to make the tires slip, you set up stiff ARB's and extension damping to make the inside rear wheel lift to create the slip.

Not following what you're saying here, but I'd be curious to hear an elaboration.

Also regarding moving ballast to the front, moving ballast forward will tend to generate understeer....to a point, the same with moving it to the rear.

This however, I disagree with. The nose weight (forward static percentage) doesn't dictate the overall balance in and of itself. As much a function of tires, springs, bars, etc. However, an incremental CHANGE in nose weight toward the rear of the car will typically be a U/S reduction - all other things being equal.

[godlameroso]

Well for a FF car, most of the weight and center of gravity is towards the front, therefore grip at the rear is the enemy of yaw in these cars. Since no drive goes to the rear to make the tires slip, you set up stiff ARB's and extension damping to make the inside rear wheel lift to create the slip.

Not following what you're saying here, but I'd be curious to hear an elaboration.

Also regarding moving ballast to the front, moving ballast forward will tend to generate understeer....to a point, the same with moving it to the rear.

This however, I disagree with. The nose weight (forward static percentage) doesn't dictate the overall balance in and of itself. As much a function of tires, springs, bars, etc. However, an incremental CHANGE in nose weight toward the rear of the car will typically be a U/S reduction - all other things being equal.

I'm just saying that with FF cars since there is no power going to the rear wheels you can't use the throttle to control slip like you would with a RWD. Therefore you must use the suspension to induce slip in the rear in order to rotate the car. My car tripods on the entry to slow and medium speed corners that require heavy braking, and settles down on corner exit. I find that it's easier to rotate the car, with less grip in the rear relative to the front, I limit this action to corner entry because that is when an FF car is at it's most "understeery", once the car has rotated sufficiently I can just power out of the corner. Then again I'm a wierdo and like doing unconventional things. My front shocks for example have a slightly stiffer setting on compression than rebound, because I want to load the outside front tires as soon as possible so the LSD can pull my car out of the corner. Sure it's a little twitchy under braking, but nothing a little bit of focus can't take care of, plus what I gain in mid corner speed more than makes up for it.

I apologize for not expressing my second point more accurately, I meant to say that moving ballast forwards will induce understeer up to a point, but this point depends on car CoG, suspension setup, chassis configuration etc. Moving it rearward will generally induce more rotation, up to a point, overdoing it however will have the opposite effect, I was using Porsche as an example of an at the limit understeery car with extreme rearward weight bias(at least relative to most road cars).

[Jersey Tom]

FF = ?

Formula Ford would ordinarily be my guess, but those are RWD...

[mkeRed]

99% sure he means front engine and front wheel drive, though I don't see why front engine particularly matters in this case.

[HampusA]

Front Engined - Front Driven
Opposite of Porsche which is RR

And rear-mid-engined layouts is MR and then we have FMR which are cars like M3 GT2, All Corvettes since the C5 i think.

[godlameroso]

As well as the FD RX-7, the RX-8 the R-35 gtr(and any car that rides on Nissan's FM platform), and the SLS AMG. Anyway back on topic, modern F1 cars are all driven pretty much the same way, the differences in driving style is minuscule. The drivers spend countless hours in the simulator, and with their engineers basically trying to figure out the best way to drive the car. Whatever differences exist boil down to a driver's reaction time, his steering and throttle control. They all take pretty much the same line, use the same braking points, and same references on the track, barring individual car differences(ie the RB7 might be able to go flat out in a particular corner whereas, a Toro Rosso might not)

[speedsense]

neither Barrichello nor Schumacher and Raikkonen block their tyres

Just because they don't lock up doesn't mean they're only braking in a straight line.

Seriously, braking straight then letting it roll to the apex then accelerating out is an amateur technique and you'd be at the back of the grid... (or not driving at a all...)

I said take a trip to youtube...
It also depends on the TYRES. If you notice a big buzz during 2007 was the former michelin teams/drivers saying how easy it is to lock up the unloaded bridgestone control tyre. TYRES play a huge role in characteristics of drivers and the adaption of their technique.

Sorry but braking in a straight line, is another technique not an amateur one. There are places where trail braking won't work such as a true street course in an open wheel car, due to a lack of grip of the track. In high powered sedans such as a race winning, well setup Trans Car, trailing the braking can cause understeer on entry where rolling in doesn't cause the same understeer.
Getting to the correct entry speed, is the only reason braking occurs. At the limit of adhesion that is a certain speed number, trail braking does not increase that number over rolling in. So you still have to slow the car to the entry speed.
With either technique, the braking point is very close and not increased in trailing brake by the distance to the apex.
Though the "advantage" of trailing brake is how the car reacts at turn in such that the car is less likely to incurr understeer on entry with a trail brake over a rolling entry that is causing understeer. IMHO

[godlameroso]

It also depend on the nature of the turn, some turns you cannot trail brake into if your goal is to go fast. Others, it's a necessity, for example on the Nordschleife, you have to trail brake into Aremberg and Bergwerk, but you can't really do it for Breidscheid. A lot of people think you need to trail brake into Brünnchen, but it's actually faster to brake straight then coast to the apex and then feed in the throttle, being careful not to spin because the apex is on the uphill. The same with the Eiskurve.

[Jersey Tom]

trailing the braking can cause understeer on entry where rolling in doesn't cause the same understeer.

the car is less likely to incurr understeer on entry with a trail brake over a rolling entry that is causing understeer. IMHO

Eh?

In any event, if you have understeer on the brakes.. why not crank some more bias to the rear? Or there are some other tricks to get the car to pivot with forward load transfer.

[PlatinumZealot]

As in brake then turn (while still on he brakes)? Makes sense..I remember the drift bible DVD where tsuchia put his Brake bias to the rear to induse more oversteer while trail braking.