Reducing understeer

[Mick K.]

I'm losing a little confidence driving my car in the wet - it feels like it is understeering quite a lot.

For those who aren't sure what understeer is, it is essentially when you turn the steering wheel and the car doesn;t turn as much as you expect and head towards the guard rail, wall, semi trailer in next lane, etc.

Is there a quick fix to this such as adjusting relative tyre pressures? I currently run on 38PSI all round and think this may be part of the problem. In the rain it feels a bit like I am driving around on ice skates.

Tyres are the standard Goodyear NCT5 Eco 205/50/16 and are about 50% worn.

If I decide to keep the Focus for a bit longer I am thinking of some suspension mods - are any mods particularly good for lessening understeer?

Cheers,

MK

[Teki04]

Maybe try better tyres? And usually in the wet you should lower your PSI a little, but not too much otherwise it will aquaplain under hard braking...

[Dark Horse]

You might want to have a go at lowering the pressures all round, I've never really had an issue driving the Focus in the wet, although I think the pressures on the Zetec are 32 all round (running Falken ZE-326 (I think??) on stock suspension.

[Uni]

i'm no expert, so please don't quote me on this, but:

understeer is a factor of inertia. to lessen the force of inertia, you need to reduce the energy which inertia amasses. thus, the distance, time, and acceleration of the vehicle in instances of direction change needs to be reduced. the obvious answer to this is to lower the centre of gravity, reduce the suspension travel, and stiffen the suspension all around.

a good spring/shock combination (or better yet a set of coilovers) will improve the understeer threshold immensely. likewise stiffer anti-roll bars and some tougher urethane (sp?) suspension bushings will also help, as will a decent set of front and rear strut braces

in terms of tyre pressures, you can try playing around, but when push comes to shove all you are doing is changing the size of the contact patch on the road, and not influencing directly the handling characteristics of the vehicle.



Uni/.

[mitch_lx]

generally stock cars will stop better in the rain.. when i say stock i mean suspension, its its low and stiff they usually slide in the wet.

Also, i have LR focus zetec 16inch alloys.. untill a few days ago i had the nct5's... Now changed to BF goodrich G-force sport's. and WHOA what a difference especially in the wet.
In all honesty half the problem is probably due to very ordinary tyres.

[FRA]

34 PSI is what you should be using man
Maybe get some new tyres.
You shouldn't have much of a problem in the wet with stock 16" on your hatch, we use to have stock 15" on our hatch and wasn't to bad/alright in the wet. Even off road the stock tyres handle alright.
The sedan was wores in the wet, put 17's on and it was alot better to drive.

[Zetec20]

i find with my car tapping the throttle til it grips and goes which leads to slight oversteer if you can handle it :P

[FRA]

After watching your Focus video, I'm sure you can handle it...LOL

[Fast Eddie]

I've had people tell me that "Tyres maketh the car". One thing to check for is the tread wear indicator on the sidewall. I think that the O.E. NCT5's on my LR Focus are 240. So the lower the TWI number maybe the better the grip?

Until recently I ran 32p.s.i. but have increased it to 36p.s.i. and have noticed better handling.

[kenny21]

Usually between 32 and 36 is alright. When I used to race my road cause i put em up to 36 and if it was understeering put fronts at 34. With the race car and this goes with all cars, if it is understeering, soften the front or stiffen the rear to basically give the front more bite or the rear more slide so to speak in simple terms. If the car handles fine when it is dry i suggest dont touch anything except maybe tire pressures cause understeer can also be a factor of ur driving style and how u drive.

Sorry uni but wat ur saying is pretty wrong if u tryin to make a car handle better it can make it worse most of the time, but if the car handles fine when its dry, try wat zetec20 said by basically steering the car the throttle or even try just lightly jabbing at the wheel a bit to try and get the front to bite in. You probably shouldnt try this on the road cause if u make a mistake u havnt got the forgivness u have on a race track haha but yea, as i said if its fine in the dry then dont touch it cause 90% sure that the suspension and handling is alright maybe just adjust ur tire pressures and maybe ur drivin style in the rain

[Pieoter]

1st get off the throttle if your on it. This cause weight transfer to the front giving you more grip and thus less understeer.

A simply mod would be up-rated rear sway bars.

[FRA]

Originally Posted by Pieoter

A simply mod would be up-rated rear sway bars.

Only problem with just changing the rear sway bars, It may produce oversteer when used with a stock front bar.
Even front strut brace will make alot of difference for a better drive and handling.
I think for Mick K, just changing tyres will make abit of difference.
Goodyear tyres are half the problem.

[mitch_lx]

Originally Posted by Pieoter

A simply mod would be up-rated rear sway bars.

You mean Actually having a rear sway bar? :P lol

Not something id trust just anyone with due to there having to be holes drilled and welding done on the car body....(not sure about focus rear suspension design, if it has a rear sway bar or not)

Not for me thanks, lower it a bit and put better tyres on the car,

That should be enough unless your going for an all out track attack.


Lets remember why this thread was started... Mick was saying he isnt very confident with his car in the wet.. Personally having driven with the eco NCT5's i have had quite a few very nasty experiences in them including understeer in wet, massive wheel spinning in wet in 1st,2nd3rd gear, torque steer when not even trying, very fast brake/tyre lockup.

All which have dissapeared since i invested in some good tyres.

Goodyear might save you once a year....Good tyres will save you much more than that :P

Also note, lowered/hardened suspension will most often make the car handle poorly in the wet (in comparison with stock). So thats not a solution to wet weather handling.

[Pieoter]

A substitute for rear sway bar is VERY hard springs on the back (The Jap tuner cars rather run hard springs than sway bars hence why imports have stupidly hard springs in them) give pretty much same result just harsher ride.

Focus has rear sway bar stock i think.

[FRA]

Originally Posted by Pieoter

Focus has rear sway bar stock i think.

Yes the Focus has a stock rear sway and front bar, you can upgrade front and rear sway bar.
Just take it easy driving in the wet Mick.

[chevaps]

Originally Posted by Pieoter

1st get off the throttle if your on it. This cause weight transfer to the front giving you more grip and thus less understeer.

This is pretty much the way to control the understeer. When in the wet, try to avoid accelerating hard around a bend or when taking a corner. Its best to ease off the throttle shifting weight to the front end allowing the front tyres to bite and do their job, which is to steer. Hittin the brake mid corner in the wet will require some quick steering action to catch the rear end

Tom

[murcod]

Originally Posted by Teki04

And usually in the wet you should lower your PSI a little, but not too much otherwise it will aquaplain under hard braking...

I'd strongly disagree with LOWERING the pressure in the wet- it should be raised. The idea is to try and let less water gather under the tread- extra air pressure should make the centre of the tread bulge out a bit further and reduce aquaplaning.

(*not that I'm saying 38psi isn't already high enough for the wet....)