330ci feel slippery on corners. With Dunlop star z1

Will it be the overboosted rack or what?
my car feel slip and lack of traction. Especially in rain.
I have bc coilover , Dunlop star z1 , on 18"
I do use 3m foam tire shine. I got a bit over the side wall, but it doesn't seems to touch the ground.
my tire are 28lb front amd 29lb rear,
I use Dunlop star before on other cars, have way better traction.
please help

pump them up to 35 psi.

225/40/18 pilot super sports and 39 on all 4 corners

It should be 32 in the front and 38 for the rears.

Mine is count in LB not psi. Could u guys help me
Convert to psi and give me a number?
and I tried to put normal air in... The rack is too light.. the only thing I could do to make it heavier is this

Are the tires new?

umm used them since July ..
But still deep tread.
Will it be the damn tire shine??
or is it because of the overboosted rack?

It only feel slip on small curve turns. not in hard big corners

What are the temps this time of year? My Toyo's traction really starts to diminish below 60 degrees. Really noticeable in chicago box cornering, not hard sweepers. Summer tires need warm temps to perform their best.

it's a bit colder now.. But its hong kong.. Only around 21 degree now . Not too bad .
Really don't think thats the problem.
I mean small cruves.. A Honda fit could tail me... and on rainy roads it's even worst..
the car just feel like it will understeer all the time.

Originally Posted by ajai

Mine is count in LB not psi. Could u guys help me
Convert to psi and give me a number?
and I tried to put normal air in... The rack is too light.. the only thing I could do to make it heavier is this

seriously?

Psi = Pounds per square inch.

Pounds = lbs.

And you're low on air. 35 lbs per square inch is where you should be at. Clear now?


Sent from my SGH-I997 using Bimmer App

Hmm... I'm thinking you might have messed up your car's handling geometry with the coilovers.

If I increase the air back up. My rack will be so lIght to drive. I lower the psi is to make the steering heavy

Should I do corner weight

Yes, get it corner weighted. It sounds like you do have the over-boosted steering rack. You really should not be lowering pressure to increase steering weight. Anything below 32PSI or so is probably not good for the tires, so raise that up.

I put it to front 30 rear 31. The rack seems the same so it's good.
But don't know if it will give me more grip yet.
Since I only drove it a bit and in rain.
but I am worry if I put it up any higher.
mine is 225/40/18 all around 18 x8 f and 18x9 rear.
Any advise ?
corner weight is expensive ..

Corner balancing won't have a significant impact, if any at all, with your slow speed understeer problem. That's for the track guys and ensuring you have equivalent balance for consistency on the track on left and right hand turns. I'd be more interested in hearing what your alignment specs are. Toe and camber can have a significant impact on low speed stability. BMW specs call for toe in which helps with high speed stability, but sacrifices initial slip angle, reducing the low speed grip.

I set my toe to zero for a better balance, and autocross guys prefer toe out generally speaking, but that's rough on the tires if you're doing highway driving.

I'm surprised I'm the first one to say it. The likeliest problem is your driving. Z1 Star Specs should not be giving you any sort of grip issues.

Otherwise if you're convinced it's not your driving style:
1) tire pressure: too low. Try 35psi all around
2) your car is too low
3) alignment. try -2.5F, -1.5R, 0 toe F, 1/16" toe in rear
4) Bushings & balljoints wearing out

Originally Posted by dreamdrivedrift

I'm surprised I'm the first one to say it. The likeliest problem is your driving. Z1 Star Specs should not be giving you any sort of grip issues.

Otherwise if you're convinced it's not your driving style:
1) tire pressure: too low. Try 35psi all around
2) your car is too low
3) alignment. try -2.5F, -1.5R, 0 toe F, 1/16" toe in rear
4) Bushings & balljoints wearing out

I am on 30 31 right now. Just to test. My shop told me try 32 and 33 .
My car is low, but not slam. on bc coilover, rear is full drop , front about half finger.
bushing balljoint are around 3 months old.

Did you have an alignment performed after the coilovers? If not, that's a problem, for sure. If so, do you remember the specs? I'm also on BC Coilovers, full drop front to rear and as long as the temps are up, I have no problems at all on tires that are not as sticky as yours.