Oversteer & Understeer

[MTI]

Oversteering and understeering are handling terms that are frequently used but often misunderstood. Simply, they describe which end of a moving car's tires/suspension runs out of grip first.

In Understeer (aka "tight"), the front end breaks free first and the car corners wide due to centrifugal force pushing the car outwards from the apex of the curve.

Oversteer (aka "loose") is the opposite, when the back end of the car loses adhesion and tries to overtake the front.

What's better, to have a car setup for understeer or oversteer?

Understeering is much more controllable and easier to handle since backing off of power usually will put the car back on line. That is probably why most road cars have understeer built into the suspensions. In comparion, most race cars will try to avoid the speed loss resulting from understeering and trust that their drivers will react and use oversteering to their speed/time advantage.

What affects the setup?

Everything. No Joke. Weight distribution, FWD vs. RWD, spring rates, caster angles, shock absorber dampening, anti-roll bar widths, staggered tires, air pressure in tires, the tire compound, Front to Rear brake bias and more.

[thumper242]

One of my favorite automotive saying of all time.


"Oversteer is when the passenger is scared. Understeer is when the driver is scared."

heh, I love it.

[Drifter]

:) Hi im new to this forum n im reli into drifting a 190E....well i own a 190E 2.0 8V carburator manual transmission...
I would like to know wat would the modifications needed for me to get my baby benz into drifting?
Coilovers?

[16v Fan]

H&R springs.... they are like 200 bucks....

[Webb]

Just about any rear wheel drive car can drift as long as its got enough power to keep the rears broken free and a stiff enough rear end to keep it sliding.

[benz_racer]

so MTI how should I set up my suspension and any weight tweaking i can do for some nice oversteer? I'm tired of the drag of understeering on my car...

[Webb]

You didn't ask me, but I'll answer anyway...

Shift as much of the weight as you can toward the back. If your suspension is adjustable, set the front up fairly hard and the rear soft. Same thing with antiroll bars... stiffer in the front and more loose in the back. Another easy thing you can do is to deflate the rear tires slightly (not outside of the limits). This will increase the slip angle (how much the tire actually bends when centrifugal forces are applied) and cause the rear end to slid out sooner. You need to be careful though. To little grip in the rear can be detrimental to drift, because you have to do a lot more work to get the car "stable" once drifting than if it didn't move around so much.

If you can adjust your camber, same deal, make it negative for more grip. I won't comment on toe because that can get a bit complicated and you can mess your suspension geometry up in a hurry if you don't know what you're doing (read: bump toe in/out).

Also, for really good drifting, a true Limit Slip diff is crucial. 190s came with a mechanically and hydrolically locking diff, but it never truely locks the wheels. The split is something like 65/35 under 30 mph and 75/25 over 30... I can't remember exactly, but even with a 65/35 split only the inside tire will break traction, and that makes drifting a lot more difficult, considering you have to be going fast enough to cornering forces to break the other wheel loose.

[benz_racer]

Originally Posted by Webb

You didn't ask me, but I'll answer anyway...

Shift as much of the weight as you can toward the back. If your suspension is adjustable, set the front up fairly hard and the rear soft. Same thing with antiroll bars... stiffer in the front and more loose in the back. Another easy thing you can do is to deflate the rear tires slightly (not outside of the limits). This will increase the slip angle (how much the tire actually bends when centrifugal forces are applied) and cause the rear end to slid out sooner. You need to be careful though. To little grip in the rear can be detrimental to drift, because you have to do a lot more work to get the car "stable" once drifting than if it didn't move around so much.

If you can adjust your camber, same deal, make it negative for more grip. I won't comment on toe because that can get a bit complicated and you can mess your suspension geometry up in a hurry if you don't know what you're doing (read: bump toe in/out).

Also, for really good drifting, a true Limit Slip diff is crucial. 190s came with a mechanically and hydrolically locking diff, but it never truely locks the wheels. The split is something like 65/35 under 30 mph and 75/25 over 30... I can't remember exactly, but even with a 65/35 split only the inside tire will break traction, and that makes drifting a lot more difficult, considering you have to be going fast enough to cornering forces to break the other wheel loose.

Thanks for the reply! didn't matter who it was as long as i got some good info.

Soooo... once i get them in (glad I did it this way now) AMG springs for the front= Stiff as... H&R for the rear=softer. good setup?

I'm trying to decide what bar to go with in the front, but now i forget which ones fit anyway. maybe I'll just get a fat one made for me. some 3/4" hex steel or something for the front and a light upgrade in the rear.

Negative camber is when the wheels look like this:
ا_/¯¯¯¯\_
|=|EVO II|=|
/--------\ right?

(lol sorry for the mini 190E i got bored)

what about tire compound?

Any other tips and tricks? I love drifting when i can do it, but it's so hard to get my car to oversteer right now!

[mde3]

Excessive camber on the rear tires (a common problem on lowered cars with no rear camber adjustment like the 190's) will tend to make the car understeer...effectively your turning radius is slightly shorter in the rears than the front as the "tracking line" is closer to the inside instead of the center or outside of the outer front tire in a turn. This also makes it more difficult to break the rears free, because as you increase side load on the rears, there is more effective grip on the outside rear tire.

The good news is when set up this way..it is very easy to hold a smooth radius in a turn by adding a bit of throttle. And you can add throttle with less fear of breaking free because there is more effective grip on the outside rear tire as you increase side load.

This understeer is different from what is being described above....because as you increase speed, your side load increases on the outside rear tire and it becomes more vertical due to sidewall/suspension deflection. At a certain side load point, the turn radius front and rear become more equal, and the car tracks smoothly around a turn with increased speed instead of speed loss. This is basically why some people feel a car with excessive rear camber "handles better" than one without. In a pure race situation however where tire life can be critical...excessive camber can lead to premature tire failure....not really a desireable situation at 150 mph.

The bad news is you need to rotate your tires more frequently.

Solution for better drifting: go to smaller diameter tires which have lower side load resistance(smaller contact patch) and allow you to apply greater torque, ie less throttle needed to break free, and thus more control. Also increasing the negative camber of your front tires will tend to induce oversteer making it easier to break the rear free(look at sprint cars)....for the same reasons listed above. Harder compounds can also help reduce grip in the rears.

.

[pradaisgood]

Are there clutch-type differential options? pumpkin swaps?

(or should I search...)

hmm.

[SergioM]

From TopGear

Richard: Now, this is really quite simple, ok? Understeer works like this: [moving a model of a Ford Focus in a straight line] you drive down the road, turn the [steering] wheel, but the car goes straight on, crashes into a tree and you die. OVERsteer works like this: [moving a model of a BMW series 3] you drive down the same bit of road, turn the wheel, but the back of the car comes round like this [showing how the car fishtails 180 degrees], and you go off the road, crash into a tree and you die. Now, oversteer is best, because you don't see the tree that kills you.

[SergioM]

Originally Posted by Drifter

:) Hi im new to this forum n im reli into drifting a 190E....well i own a 190E 2.0 8V carburator manual transmission...
I would like to know wat would the modifications needed for me to get my baby benz into drifting?
Coilovers?

ASD