metaphysical

iTrader: (3)

At my last autocross, I was lifting my rear inside tire during hard turning. Now, the first question, is this a bad thing? (Some of the fastest cars there lifted their inside rear) How can I combat this if it is a bad thing (Which I would imagine it is)? I want to keep the car oversteering, but would like to get as much traction as possible.
(And I'll be purchasing RRE JIC setup this week also, how much will that make a difference with tire lift)

My car:
Progress 25mm rear sway bar set on full stiff
Tein S-Tech
Camber -1.8 Front -1.5 Rear
Toe 0

whitet777

iTrader: (6)

I have noticed that rear wheel lift goes up with increased rear swaybar stiffness. You could back off from full stiff. I also noticed my rear wheel lift has gone down with increasing the front stiffness some, but at the expense of a little bit more understeer (not much). I did this with the front swaybar modification. Logic would also suggest that stiffer springs all around would help, but I haven't noticed my Tanabe GF210's helping much.

I would also say that rear wheel lift isn't that bad of a thing. I have also seen it on many very expensive cars that do very well autocrossing.

I have heard that coilover's will help with wheel lifting, but I can't afford that.

nothere

iTrader: (23)

hey, the dog going to the bathroom look is very cool. don't fight it

992gnt

iTrader: (5)

Here's mine lifting on the racetrack at around 50 mph. Didn't seem to slow me down much. I have the Tanabe's, and the Progress rear bar. Car was very neutral - even with 1 wheel in the air.

whitet777

iTrader: (6)

I would lift my inside 5 to 6" on a tight autocross track. Car still felt neutral though and cornered very well.

erioshi

I expect the the RRE JICs will stop your wheel lift. There is one track that I run on that with the stock suspension I was always lifting the inside rear wheel. After I installed my JICs both rear tires stayed planted.

metaphysical

iTrader: (3)

Good to hear! I don't want to create understeer to compensate for the rear wheel lift.

chrisw

iTrader: (2)

coilovers will reduce the wheel lift, but not totally cure it.

jbrennen

iTrader: (1)

I think that all 3 Evos running at the Oscoda ProSolo this past weekend were lifting the inside rear wheel. All of them are running upgraded suspensions -- stiffer springs, etc. -- which reduce the lift but don't eliminate it.

Personally, I haven't found that lifting the inside rear tire is causing problems for autoX.

With regard to sway bars, either a smaller/softer rear bar or a bigger/stiffer front bar will decrease the ability of the inside rear tire to lift. Either change would also tend to cause understeer. I'd say go for a handling balance that works for you rather than trying to keep the tire on the ground.

jwtodd60

I went to a bigger front bar (25mm Cusco + Cusco adjustable bracket set to 116%), not so much to keep the rear tires on the ground, but to try to minimize the beating the outside shoulder of the front tires were taking. Frankly, I don't think that it made a big difference, but it is one of the few mods allowed in A Stock, so there it is. If you look at these pics, you will see I'm still getting plenty of inside rear lift:

http://www.photoreflect.com/scripts/...um=0&adjust=-1

http://www.photoreflect.com/scripts/...um=0&adjust=-1

(I did buy the CD with these photos, but I don't have it with me)

JW

93esp

iTrader: (4)

Inside rear tire lift is not an ideal situation. On this car it's caused from a combination of roll axis angle, lack of rear suspension droop travel, and excessive body roll. Upgraded suspension will not cure the problem by itself and the additional degrees of freedom can actually make it worse. At the Oscoda pro I was actually pulling both inside wheels off the ground.

Eric

jbrennen

iTrader: (1)

Yes, I agree. It's not the ideal situation. But it may be better than some of the alternatives.

Under very hard cornering -- but not hard enough to lift the inside tire -- the body of the car leans and the dynamic camber of the rear tires changes. In particular, assuming that you have an appropriate alignment for autoX, the outside rear tire has a much larger and flatter contact patch than the inside rear tire. The inside rear tire might have only the inside inch or so of the tire actually touching the ground. Transferring weight away from a camber challenged tire to a tire which is in its camber sweet spot is not necessarily a bad thing.

Visible lift of a tire is certainly just wasted energy. But making large suspension changes in order to keep that inside rear tire planted has to be done very carefully, as you will likely compromise other aspects of the car's handling.

urbanknight

iTrader: (14)

I think that's a good idea. Contrary to my former belief that such would cause understeer, a hot topic on sccaforums.com suggests that it will reduce body roll, keeping the front tires firmly planted, while keeping some of the weight transfer off the front. I'm only lifting maybe 3" on my inner rear in my FWD, but after I get a higher spring rate, I might be upgrading the front bushings and maybe the bar myself.

ColinL

Looks like I'm late, you guys have it all covered.

Anyway, I agree with UrbanKnight-- a larger front bar will not necessarily increase understeer. Pictures of your car under heavy cornering will tell you if there is still significant body roll-- if so, then putting on a bigger front bar could help that a lot, by keeping more of the outside tire in contact with the road.

A bigger front bar, or smaller rear, is definitely the correct first step to keeping the inside rear tire on the ground. BOTH tires off the ground on the inside sounds a lot like too much bodyroll and ride height for the traction available-- back when people were running them, I used to see Stock class Golfs doing that pretty often. Scary.

I personally think the Evo's stock f/r balance is pretty neutral, very neutral compared to the STi's moderate understeer. For whomever had a big rear bar and stock front, I'd definitely suggest a bigger front bar, and yes adjustable would be really nice.

93esp

iTrader: (4)

Most Evo's I have seen do not pull the inside rear tire off the ground at the limits of cornering. If you watch most of these cars they will pull the inside rear off the ground on turn-in which indicates a sharply declined roll axis with insufficient front roll stiffness and insufficient front track width. When the inside rear is jerked off the ground the outside front is carrying more weight than it should and is operating at a less than ideal camber angle. The wheel lift problem can be corrected without negative tradeoffs it's just a matter of finding the correct combination.

Eric