Understeer and Oversteer

[CorneliusRox]

So I know that the most common handling issue with AWD is the understeer, but I want to know everyone's take on it.
For those who dont know:


Understeer (green is where you aim, red is where you go)

Oversteer (green is where you aim, red is where you go)

My car which currently has coilovers, 255/35-18 V12 tires, and a stg1 tune, seems to act different than what everyone tells me about this car.

When driving aggressive, if I take a turn hard but push in the clutch and roll in neutral, I get understeer, and slide forward.

When downshifting and putting down some power (not even close to WOT), I get oversteer. (very controllable)

And when going into a turn in neutral and start getting understeer, I just give gas and get oversteer.

It doesnt take much power to get the rear tires sliding out, and I was curious about that since everyone seems to say they get the worst understeer even, even with an RS4 rear sway bar (which I dont have).
So tell me how your car behaves in the twisties because at this point, an RS4 RSB is not something I think will improve my performance much.

[yayjohnny]

I've never oversteered in my car before, and I've always downshifted and accelerated out of the corner. All the time is understeering

[GAIC Husky]

When I start to get understeer I just give it some throttle and I can get it to behave the way I want it to. I usually can't get the rear to kick out to the extent of oversteer unless its wet out and I'm being really aggressive.

*Understeer scares drivers and oversteers scares passengers.

[Dat Black Kid]

If you're under steering, that means you're entering and trying to take the turn faster than your tires can handle. I can understand my under steer, since I driving on roads made of marble and concrete mixed. I do the what johnny does, downshift, and accel out.

[vdubjetta02]

I Overtseer my cars on purpose..... In both my A4 and S4, I go into a turn about 10 MPH hotter than I should and I "Snap oversteer" the wheel causing the rear end to kick out, once it kicks out I get back on the throttle and let my quattro do what it does best

[CorneliusRox]

I go into the turns, usually at 4000rpm in either 2nd or 3rd depending on the turn and usually it starts to understeer just a bit and then I power through and get just enough oversteer to almost drift a little. The roads here are oil soaked though. I have some pretty hefty meats on my little A4 though.

[rjkotler]

1. Oversteer and understeer can dramatically be affected by weight transfer. So entering a turn under power, with a little throttle and in neutral will have big differences. Finish braking just as you begin your turn, a little throttle to keep the car balanced as you apex then as you unwind the wheel throttle on.

If you are going around a turn near the limit of traction with a steady throttle and then let off mid turn all of a sudden you will transfer weight and traction to the front and off of the back and you will get oversteer. Fun stuff if there is not a wall nearby.

Conversely.

If you are going around a turn and get on the gas too soon you will shift weight aft and pull traction off the front tires and get understeer. Not fun as you plow your way off the road.

With a little practice you can go around a turn (at the traction limit) with the steering wheel in 1 set position and use the throttle to steer by shifting weight and grip fore and aft to induce slip.

As for the RS4 Sway bar I would say you should get it. Your car will have less body roll in the turns and your tires contact patches will stay flatter giving you more over all grip. The RS4 sway is the best upgrade I have done to my B7 A4. In my B6 S4 I am doing the Hotchkiss Front and rear sway bars this weekend to help prep me for an Autocross event in a couple of weeks. I expect a pretty big difference on how it handles.

[shiro1745]

You should never enter a turn in neutral, specially when you drive hard. It's easy to control over-steer by releasing pressure on the throttle and even easier if you're in a lower gear at higher RPMs

[jimrobbington]

I've never really felt like the car understeers really, but I have also only driven fwd cars my whole life. I usually start a turn with zero throttle and burst through the turn with full throttle, always trying to get the rear loose. Never comes loose, unless it's wet. I'll get a little screeching, but it's always under control. Really only time I had under steer was in an auto x event where you have a 1st gear 180° turn.

[Adub-Drew]

OP, i see where your coming from too, a week ago i was on oem suspension and it always felt like front plow going through corners. Now with the coilovers on, it almost feels like a four wheel steering/ toe in on the rears, it kind of goes in with the turn and takes it much better now. I though it was oversteer at first but its not. I pushed a little harder and the understeer came back. My conclusion is that if i do "lively" driving at speeds that i did with stock suspension it feels like oversteer, but push a little harder and that heavy nosed audi will come back into its element. I honestly think, no matter what people do to the car, that understeer will always be there because of the motor being so far forward, sure that threshold can be set back with extensive suspension mods, but at the end of the day it will always be there. Then again if you were to mess with diff settings and send more of the power to the rear and make it better for a neutral handling etc. But at that point its probably a better idea to just get into a different car with a better chassis. I drive my dad's e90 quite often, and as much as i hate going to the dark side, i really see myself going into a e90 or a 1 series in the near future. In term's of driving fun, the bmw takes it hands down.

[CorneliusRox]

OP, i see where your coming from too, a week ago i was on oem suspension and it always felt like front plow going through corners. Now with the coilovers on, it almost feels like a four wheel steering/ toe in on the rears, it kind of goes in with the turn and takes it much better now. I though it was oversteer at first but its not. I pushed a little harder and the understeer came back. My conclusion is that if i do "lively" driving at speeds that i did with stock suspension it feels like oversteer, but push a little harder and that heavy nosed audi will come back into its element. I honestly think, no matter what people do to the car, that understeer will always be there because of the motor being so far forward, sure that threshold can be set back with extensive suspension mods, but at the end of the day it will always be there. Then again if you were to mess with diff settings and send more of the power to the rear and make it better for a neutral handling etc. But at that point its probably a better idea to just get into a different car with a better chassis. I drive my dad's e90 quite often, and as much as i hate going to the dark side, i really see myself going into a e90 or a 1 series in the near future. In term's of driving fun, the bmw takes it hands down.

I thought the 135i was pretty sweet until I was in a TTS, and now I want a TTRS. ;-)

I think going to coilovers helps A LOT! and I am sure these cars will always have understeer issues, but I think it might be like rjkotler was saying where once you get it to be relatively balanced suspension wise, you can steer with the throttle. I will probably get a thicker rear sway bar eventually, but it's not high on my list right now. I just wanted to get some feedback on what people have found with the B7's. Hopefully swoardrider gets in here because I know he tracks his car a lot.

[Charles.waite]

I've never really felt like the car understeers really, but I have also only driven fwd cars my whole life. I usually start a turn with zero throttle and burst through the turn with full throttle, always trying to get the rear loose. Never comes loose, unless it's wet. I'll get a little screeching, but it's always under control. Really only time I had under steer was in an auto x event where you have a 1st gear 180° turn.

My Non-Sport b7 understeers like crazy on stock 17" with 235/45 Conti DWS. Of course thats to be expected. My B6 USP is more neutral, though still understeers , with 235/40 R18 Yokohama YK520. Those are still crappy tires though so I'm blaming it on the tires until I decide to bite the bullet on some Hankook V12s.

[Charles.waite]

I Overtseer my cars on purpose..... In both my A4 and S4, I go into a turn about 10 MPH hotter than I should and I "Snap oversteer" the wheel causing the rear end to kick out, once it kicks out I get back on the throttle and let my quattro do what it does best

Thats not oversteer. Thats kicking the tail out. An S4 has almost enough power to really maintain a slide, but not an A4. Unless you're running slippery All Season tires on gravel...

[vdubjetta02]

Thats not oversteer. Thats kicking the tail out. An S4 has almost enough power to really maintain a slide, but not an A4. Unless you're running slippery All Season tires on gravel...

"Snap oversteer" and "lift off oversteer" are actual driving techniques.... I understand where you are coming from, but it is a driving technique used by many rally drivers resulting in oversteer

[CorneliusRox]

Make the jump! I love my V12's. I'm on 255's and I think I could squeeze 265's if I threw on a little bit thicker spacers, but it would be close.
Anyways, they changed the limits of my car a great deal.

My Non-Sport b7 understeers like crazy on stock 17" with 235/45 Conti DWS. Of course thats to be expected. My B6 USP is more neutral, though still understeers , with 235/40 R18 Yokohama YK520. Those are still crappy tires though so I'm blaming it on the tires until I decide to bite the bullet on some Hankook V12s.

[B-Time]

"Snap oversteer"

^ aka Scandinavian flick.

Understeer is when your nose hits the wall. Oversteer is when your tail hits the wall. Horsepower is how fast you hit the wall and torque is how far you push the wall.

[LuckyNumberB7]

It's all about contact patch management.

[boostin20v]

Understeer is when your nose hits the wall. Oversteer is when your tail hits the wall. Horsepower is how fast you hit the wall and torque is how far you push the wall.

LOL

[Charles.waite]

"Snap oversteer" and "lift off oversteer" are actual driving techniques.... I understand where you are coming from, but it is a driving technique used by many rally drivers resulting in oversteer

I know what you're saying, but:

http://www.youtube.com/watch?v=7Le5JX0MdYY

THAT is what I call oversteer. I guess I was thinking more powersliding, rather than a momentary oversteer situation...

Or in Audi terms here: http://www.youtube.com/watch?v=mtMR-cqiiDw

[jimrobbington]

That's exactly the power I want someday.

[Charles.waite]

That's exactly the power I want someday.

Dude I know. the 2.7t is just a beast.

[yungcotter]

My Non-Sport b7 understeers like crazy on stock 17" with 235/45 Conti DWS. Of course thats to be expected.

Have the same setup Lol you know the feeling. Ive come in too hot to some turns was almost not pretty.

[jimrobbington]

Have the same setup Lol you know the feeling. Ive come in too hot to some turns was almost not pretty.

I can see that. I've been lowered on 19x8.5 for a long time. I don't even remember how bad it might have once been. I really want to throw on a RS4 RSB soon. Hoping it helps make the rear end a little more fishy.

[swoardrider]

Lots of confusion between oversteer, under steer, power sliding, plowing, etc. The end of the S4 video is a good example. Look at how hard the front tires are being pushed. He's actually inducing under steer because he has enough power to break the front traction loose and power slide the rear at the same time. I wouldn't call anything I saw in the video "oversteer".

Example of oversteer would have been if the drive was doing that in a Lotus Elise. Front tires would of pointed the car wherever the driver wanted to, but as soon as the driver let of the gas, that tail would of whipped around hard.

[TMurt]

[VroomVroom]

I'm enjoying this thread. Pardon the slight tangent....



USS Harry S. Truman, undergoing recent sea trials. This was a full power, "rudder swing check," resulting in a 13-degree list...shoulda' gone with the RS4 anti-sway bar.

[Jeff129]

Good job!

[CorneliusRox]

It's all about contact patch management.

That's a good point. I did some more attempts to figure out exactly whats going on, and possibly I need just a little bit more neg camber on the rear. I already have it all set up for twisties, but I guess more neg cam in the rear or a thicker rear swaybar.

If I am keeping the steering wheel at the exact same spot and steadily accelerate in a large radius circle, my rear slides out before my front does, however if I am decelerating and pulling the wheel in more and more, the front will push through (like it should).

[Stewy]

In addition to the suspension mods I've done (RS4 sway bars and coilovers), the biggest change in driveability and balance came with the 4:1 center diff swap. My car doesn't shovel its way through corners any more and it really feels a lot 'lighter', hard to describe. Those that have done the mod will know what I'm talking about.

[Khaotic]

This is how I wish my quattro would drive..

But more on-topic, if I go to fast into a corner I will have understeer if I turn in to hard, but if I enter the corner more slowly and power on through I can get it to oversteer quite easily.. However its alot because I run cheap chingchong tires atm and the grip is quite shit..

[Shanster]

...chingchong...

nice

[georgio3gr]

1. Oversteer and understeer can dramatically be affected by weight transfer. So entering a turn under power, with a little throttle and in neutral will have big differences. Finish braking just as you begin your turn, a little throttle to keep the car balanced as you apex then as you unwind the wheel throttle on.

If you are going around a turn near the limit of traction with a steady throttle and then let off mid turn all of a sudden you will transfer weight and traction to the front and off of the back and you will get oversteer. Fun stuff if there is not a wall nearby.

Conversely.

If you are going around a turn and get on the gas too soon you will shift weight aft and pull traction off the front tires and get understeer. Not fun as you plow your way off the road.

With a little practice you can go around a turn (at the traction limit) with the steering wheel in 1 set position and use the throttle to steer by shifting weight and grip fore and aft to induce slip.

As for the RS4 Sway bar I would say you should get it. Your car will have less body roll in the turns and your tires contact patches will stay flatter giving you more over all grip. The RS4 sway is the best upgrade I have done to my B7 A4. In my B6 S4 I am doing the Hotchkiss Front and rear sway bars this weekend to help prep me for an Autocross event in a couple of weeks. I expect a pretty big difference on how it handles.

+1

With bold is the right way turning your car by following the best driving line so you have neither understeer nor oversteer...

[CorneliusRox]

+1

With bold is the right way turning your car by following the best driving line so you have neither understeer nor oversteer...

I do that on my bike, I like to get a little crazy in my car since there are four wheels and a cage around me ;-)
That does usually make the fastest pass though.

[Adub-Drew]

I thought the 135i was pretty sweet until I was in a TTS, and now I want a TTRS. ;-)

I think going to coilovers helps A LOT! and I am sure these cars will always have understeer issues, but I think it might be like rjkotler was saying where once you get it to be relatively balanced suspension wise, you can steer with the throttle. I will probably get a thicker rear sway bar eventually, but it's not high on my list right now. I just wanted to get some feedback on what people have found with the B7's. Hopefully swoardrider gets in here because I know he tracks his car a lot.

But you run into the same problem with the tts/ ttrs. Push it enough, and it too will start to understeer. BMW is just more tossable, goes where you want it to and just overall a sensation to drive imo. I mean i just installed the coils on my car, but the e90's stock suspension is still better..

[CorneliusRox]

But you run into the same problem with the tts/ ttrs. Push it enough, and it too will start to understeer. BMW is just more tossable, goes where you want it to and just overall a sensation to drive imo. I mean i just installed the coils on my car, but the e90's stock suspension is still better..

Yeah, RWD is a different animal for sure. And I am not really impressed by the e90 platform suspension, or any audi platform. I doubt a production car will really get too crazy with suspensions ever, but I would like to see a toe in suspension the goes toe out while compressed, and has an aggressive neg camber change on compression. Stuff like that isnt good for ppl who just want to DD though. Dang, I need to make my own car. (been wishing to do that for years. Maybe in the next 10 years I will)

[martin0079]

That's exactly the power I want someday.

Dude you can pick up a decent stage 3 B5 S4 for 10k I bought one after I got my A4 to stage 2+

[LuckyNumberB7]

That's a good point. I did some more attempts to figure out exactly whats going on, and possibly I need just a little bit more neg camber on the rear. I already have it all set up for twisties, but I guess more neg cam in the rear or a thicker rear swaybar.

If I am keeping the steering wheel at the exact same spot and steadily accelerate in a large radius circle, my rear slides out before my front does, however if I am decelerating and pulling the wheel in more and more, the front will push through (like it should).

I was thinking more along the lines of weight balance and acceleration/deceleration but that works too.

[CorneliusRox]

I was thinking more along the lines of weight balance and acceleration/deceleration but that works too.

That's almost completely based on spring rates and sway bars, Not suspension geometry.

[LoKisSpYdR]

640 mod. It will now drive as if were on rails.

[LuckyNumberB7]

That's almost completely based on spring rates and sway bars, Not suspension geometry.

I'm referring to how the area of your tires that is in contact with the road will change based on how you are accelerating, braking, turning, etc. The total amount stays the same, how it is distributed changes. You can transfer weight to counter or induce understeer or oversteer.