Fatter rear tyres to cure oversteer

[Shaun]

going from 225s in all 4 corners to 245s in all 4 corners will increase the overall limit but the oversteer tendency will remain unless it is power oversteer which will still largely remain with the 245s though they help somewhat.

if you run larger tires in the rear only while leaving the fronts at 225 then tire rotation is going to be a problem. $$$

might be easier to run an adjustable front sway bar and increase roll stiffness at the front . or if z4s come with adjustable camber then try messing aroud with that in the rear.

 

[Tanzy]

Shaun,

Thanks for the advice! Ya, tyre rotation goes out the window with staggered arrangements. Forgot about that. :thinking:

It's power oversteer that is the problem. I tend to misjudge and apply power too early into the turn and the DSC is more retarded than I expect, so the tail end comes out. It's still quite progressive and not snapping out like a S2000.

I'll most likely have a look at the sway bars. They are suppose to be M suspensions but I have no idea how thick they are.

Adjustable camber sounds interesting but I don't think the Z4 has that option.

 

[Shaun]

is your car manual or auto?

a cheap and very fun option is to attend a trackday with the guys here and get used to controlling the car as it is.

 

[Tanzy]

is your car manual or auto?

a cheap and very fun option is to attend a trackday with the guys here and get used to controlling the car as it is.

It's an automatic.

Would love to go to the track with it. I went to Tuas today and was practising on the deserted 6 lane roads leading to no where. Very fun!

 

[Shaun]

cool then the oversteer should soon be controllable. track will be very different because the Gs are sustained and at much higher speeds and larger radii.

 

[peterlaw]

controlling oversteer? that sounds interesting. in the first place, how to get the car to go into oversteer. my car has 17" 245s and no DSC.

it's about time to get more juice out of the humble a-to-b runner.

 

[Tanzy]

controlling oversteer? that sounds interesting. in the first place, how to get the car to go into oversteer. my car has 17" 245s and no DSC.

it's about time to get more juice out of the humble a-to-b runner.

Always works for me.
1) Big traffic junction. Right turn arrow flashing.
2) Accelerate to 100km/h to beat the light.
3) Enter decelerating right turn lane.
4) Get on to the brakes. Bring it down to about 80km/h
5) Release the brakes and enter turn.
6) Once the car is pulling lateral G, Floor the bugger!
7) Get ready to countersteer cause the tail will step put.
8) Inshallah, you will survive to post here again.
Preferably when the road is moist.

Are you nuts!?! I am trying to prevent oversteer and you want it?
:screwedu:

 

[Shaun]

in the first post you say that you've had a few hairy moments too many, and then in this latest one you say you "floor the bugger"? Former hints of oversteer being unwanted and happening unexpectedly, yet latter is clearly induced and "always works for me" suggests you do it often.

mind boggling. not sure whether you want or do not want the oversteer.

 

[Tanzy]

in the first post you say that you've had a few hairy moments too many, and then in this latest one you say you "floor the bugger"? Former hints of oversteer being unwanted and happening unexpectedly, yet latter is clearly induced and "always works for me" suggests you do it often.

mind boggling. not sure whether you want or do not want the oversteer.

I'm replying to peterlaw! Again, I'm just kidding with him. I'm describing how oversteer happens for me. I was in Tuas today learning my car and I found out , as I suspected, that the problem with me is applying power to early.

 

[Shaun]

orrh

 

[E46]

Today I oversteered at 25 kph while making a right turn on a wet day :twisted: Pretty cool.

Though I understeer while turning right in the MSCP at walking pace when I tap on the accelerator pedal at gear 1. It just went straight ! scared me for a while :roll:

 

[Racebred]

Tanzy, best way I recommend for your problem is to control the driver, not control the car. knowing what to do at different situations is a much better method than flooring the bugger all the time and let electronics help you out. And it's cheap. basically $0.

have u attended the ADT? it's basically like a tuas excursion, except it's more expensive and comes with a buffet lunch. you can learn some car control stuff from there.

changing to 245 is going to increase the chance of aquaplaning, which in my opinion, is definitely more scary than power oversteer, especially in a lighter car like the z4. so i suggest you just stay there.

the only time you should change to wider tyres, is when you're making so much power that all the power is changed into just spinning your rear wheels when you do a launch.

for handling aspects, use aftermarket suspension upgrades to help control your power. i think your car comes with an LSD, and it's simply just adding more fun to your ultimate driving machine. thats how BMW builds their cars for their customers. Merc SLK has another philisophy and thats why you see that you can never truly switch off their traction control.

so your car behaves this way coz bmw purposely builds it like this. in any car i drive on the track, i always switch off the traction control, coz controlling your car with your right foot is really like 75% of all the fun already.

 

[Shaun]

the only time you should change to wider tyres, is when you're making so much power that all the power is changed into just spinning your rear wheels when you do a launch.

Have to disagree... I believe there is big improvement in cornering grip by the contact patch expanding laterally and that it is a lot more about cornering than straignt line acceleration.

 

[Charontes]

I'm replying to peterlaw! Again, I'm just kidding with him. I'm describing how oversteer happens for me. I was in Tuas today learning my car and I found out , as I suspected, that the problem with me is applying power to early.

hmmm.. i tot it's too much braking during cornering tt causes oversteer?
if u apply power, weight shld shift to the rear, rear wheels gain grip, front wheels lose grip n u will understeer instead...
correct me if i'm wrong.

 

[Shaun]

enough power will break traction at the rear since it is RWD and will cause it to slip. there are many ways of getting to an oversteer condition. you can brake, or lift sharp off the throttle, or jump on the throttle, or downshift, or a combination of these.

 

[Racebred]

yep they call it the braking-drift, the lift-off oversteer, the power-over, the shift-lock. lets not forget our trusty handbrake!! hehehe

oversteering can also occur at aquaplannning conditions, mid-corner bumps, and trying to sms while approaching turn 7 in sepang.

 

[peterlaw]

how about increasing negative camber?

i was told that a negative camber can improve cornering and handling performance. perhaps it can cure the oversteer? here's something to consider http://catalog.com/susq/other/stuning.htm

 

[MRacer77]

No, negative camber cannot really cure oversteer per say. But getting a set of coilovers will go a long way to improving the handling and makes controlling the oversteer easier.

RB, you have been watching the Drift Bible is it?

 

[Racebred]

i havent seen it. anybody got it? can burn a copy for me?

 

[MRacer77]

Yah yah... ok... I will burn a copy for you.