Need help with understeer and holding curves

Just got new tires (225/45-17 RE960's) to replace my wore out Kumho Supras that were on the car when I bought it. I can't afford to have a second set of rims and tires right now so I had too go with All Season tires. I've noticed that on long fast curves, such as highway exit and entrance ramps, the back of the car comes out at lesser speed. I autocrossed the car yesterday though and had major understeer, worse than before. Mods are stage 1 tune and Cobb F+R sways. Rear sway is on the loose setting.

I'm trying figure out what to do here. I have a "30 day try and buy" on the new tires, but I'm not sure I can find a better tire for year round that is cheaper than my RE960's. I got them at a 20% discount, installed with road hazard for $735. I'm thinking maybe I should look into suspension upgrades in a month or so.

Car has 63k miles on the stock suspension (except the sways). Should I be thinking about new struts, sport springs, or something else all together? Ride comfort takes a back seat to performance and safety for me.

You could always play with alignment and air pressures. Also, if the front bar is adjustable put that on the soft setting and change the rear to stiff.

Front bar isn't adjustable. If I put the rear bar on the stiff setting, would that cause the rear to step out earlier on the curves on the roads?

 

I'm guess the stiff setting might help a little in autocross. The major problem I had in autocross was in the box turns. The car would push and I would have to almost stop to keep from plowing cones near the exit of the box. I had a veteran ride with me for a lap and he said that while my driving technique could use some tweaking it was more the car than me causing the understeer.

Start with an aligment.. some negative camber and slight toe out can help a lot with turn-in. Make sure the front tires have enough pressure. For a tight course, I add a few pounds to the front tires to make sure the sidewalls aren't rolling over.

Definitely change the rear bar to the stiff setting. It may help more than you think.

 

Cheers!

Step 1. alignment. max negative front camber. zero the toe for best tire wear, easiest driveability.

 

Step 2. Drive the car again.

 

 

- drew

Front bar isn't adjustable. If I put the rear bar on the stiff setting, would that cause the rear to step out earlier on the curves on the roads?

 

I'm guess the stiff setting might help a little in autocross. The major problem I had in autocross was in the box turns. The car would push and I would have to almost stop to keep from plowing cones near the exit of the box. I had a veteran ride with me for a lap and he said that while my driving technique could use some tweaking it was more the car than me causing the understeer.

 

A stiffer rear bar adds oversteer.

Tail coming out early on long fast turns happens if you-

1) were carrying too much speed into your turn

2) were trail braking and hit your brakes while you were turning, causing more weight to shift to the front

3) turned your steering wheel too fast

4) too much throttle too early

 

The understeer can be attributed to your tires being pretty new still, and also if it's wider than you're used to. Once you break in the tires after a couple thousand miles, your tires in front will wear down a little more, which should help with turn in and reduce your oversteer. Youl'l also get a better feel for how much speed you need to get your car to rotate properly.

 

If you just want a quick fix, +1 to what everyone said already...play with tire pressures, change to stiffer rear sway bar settings, negative camber, and good alignment

Highway off ramps and entrances are usually concrete pavement opposed to black tar. I find that the concrete offers far less grip the black pavement, this could be your problem.

I used camber bolts up front and aligned the car as Drew suggested. Its an easy way to get -1.0 negative camber for $35.00. You may also want to consider replacing the struts. At 60K mine were going bad, as we all know the struts were not matched well from the factory so a worn strut only makes it worse. Plus no matter what you do to the rest of the suspension if the tire isn't contacting the road consistently and instead bouncing off the road the car won't handle as well as it should.

Is alignment a DIY job? Haven't found any threads on diy alignment.

What's the best way to test struts to see if they need replacing?

I used camber bolts up front and aligned the car as Drew suggested. Its an easy way to get -1.0 negative camber for $35.00.

 

you should be able to get more than that with the stock bolts, mine maxed out at -1.75.

Is alignment a DIY job? Haven't found any threads on diy alignment.

What's the best way to test struts to see if they need replacing?

 

i'm almost certain alignment cannot be "DIY" unless you have the calibration equipment to do so, i mean i've heard of people who can figure it out with a spirit level to some degree but it's best to just take it to a shop who can get it done for you.

I put the bolts in the opposite hole to the instructions. TIC suggested this to minimize bolt slippage.

 

Alignments can be done at home and be done very well, my friend and I have done three so far. For the first time my wheel is straight when the car goes straight, the dealer could never do this. We used Smart Strings http://www.bbxracing.com/product_info.php?products_id=74. You will also need some slip plates and the camber gauge. There is also a less expensive way of doing home alignments detailed on NASIOC. Its not quite as good but will get you close.

Is alignment a DIY job? Haven't found any threads on diy alignment.

What's the best way to test struts to see if they need replacing?

Alignments: As ifbiker said, it's possible to have it DIY... just as he described. Of course, it's not cheap (as you can see from the price on his link). You could do it with "non-Smart" strings, haha... but in the end, it might just be easier to take it to a shop, unless you plan on doing alignments often.

 

As for struts - they don't wear out the same way as shocks do - the old shock-test being to bounce the car, and see how many times it oscillates. You can't do that with struts as reliably.

 

If you're using aftermarket springs on stock struts, then you're probably going to need new struts (stockers can't handle the increased spring forces). Struts and springs should always be "matched". If the car is older, then you can safely "assume" the struts are not good, as well. you can also look a the strut cylinder and see if you see any oil on it... if it's leaking then it's certainly bad.

I don't understand this - I have read that the Legacy will outhandle just about any car and now I read this

I don't understand this - I have read that the Legacy will outhandle just about any car and now I read this

 

yes I was quite shocked when I discovered that a 3300lb. sedan with a coat hanger for a RSB, MacPherson struts and tennis balls for LCA bushings actually had the nerve to exhibit understeer.

 

Seriously though, if you put the RSB on the 'tighter' setting you will take some traction away from the rear wheels - resulting in a more neutral feel. It doesn't mean you're going to spin out on every street corner. The primary cause of understeer is simply that the rear is getting more traction than the front - so you can either give up some traction in the rear (tighter/larger rsb) or add more traction to the front (neg. camber, PU bushings, etc.). Whenever you make a change to the rear you have to consider the setup in the front, and vice-versa.

A stiffer rear swaybar increases front grip....it doesn't simply reduce rear grip. Yes, if you go too big it will reduce rear grip.

 

 

- andrew

A stiffer rear swaybar increases front grip....it doesn't simply reduce rear grip. Yes, if you go too big it will reduce rear grip.

 

 

- andrew

 

indirectly yes, but the increased front grip is a result of the reduced roll in the rear being transferred to the front. More front roll means more front grip. Like I said you can't change one end without affecting the other.

this is all under the assumption that the rsb is thicker/stiffer than the front btw.

How does changing the camber affect tire wear?

Depends on how often you drive aggressively

Camber with toe will effect tire wear because the tire "scrubs" as it goes along the road.

you'll also experience more pronounced tracking with negative camber - where the car exhibits a tendency to follow banks & imperfections in the road. Feels wonderful at the track, but can be annoying on the street. I found the Whiteline roll center/bump steer kit helped to alleviate this some.

 

OP: just a suggestion but if you're looking to make the car more neutral you should think about stiffer springs/dampers instead of relying on only the sways. It's a false sense of security that will become scarily apparent when the car is pushed to the limit, as you may have discovered while autox'ing.

It's probably been said thousands of times before on every car forum, but a good spring/strut combo will take care of 90% of your understeer. The sways should be used to fine tune where exactly you want the remaining roll to go.

indirectly yes' date=' but the increased front grip is a result of the reduced roll in the rear being transferred to the front. More front roll means more front grip. Like I said you can't change one end without affecting the other.[/quote']

 

So lets say I put a stiffer rear swaybar on the car, it would reduce rear body roll and increase front body roll by your explanation.

 

Then if i get a bigger front swaybar, it would reduce front roll and increase rear body roll.

 

If I did both, would I then be back to square 1 and have the same amount of body roll I started with?

 

The answer is no.

 

I think you're getting body roll and weight transfer mixed up.....they are not the same.

 

Adding more rear roll resistance, whether through stiffer springs or stiffer swaybars, increases rear weight transfer. This means the front sees less weight transfer since total weight transfer stays the same in a given corner for a given car (except if you change track width, weight, COG, etc.)

 

Reducing weight transfer at the front (with a stiffer rear swaybar) means more even loading of the front tires, which means more grip up front. But it doesn't mean more front body roll.

 

Increasing weight transfer at the rear (with a stiffer rear swaybar) means more uneven loading of the rear tires, which means less grip at the rear. You do get less body roll in the rear, which can add some grip back by reducing suspension geometry changes.

 

- Andrew