MZM

After three 20 minutes sessions at Streets of Willow, my near new tires look like this. The car is totally stock. As is evident, the left front tire is toast. Wear decreases from lf through rf, lr, then rr.

I would expect this since most turns are right handers. Look Here

This is a symptom of weight transfer to the outside front. In turn this causes understeer and heavy tire wear. My idea is to alter weight transfer using a stiffer rear anti-sway bar, higher tire pressure, and maybe stiffer front springs.

Do you guys agree? Any other ideas to help the situation? What would you do? Thanks.

Mike McBride

PS I hope the attachments worked. Can't tell.

dropkick_muppet

iTrader: (4)

the attachments don't appear to be working, but the link to the willow track map is.

stiffer/larger diameter sway bars are not going to help your fore/aft weight transfer issue. the only real way to address the fore/aft weight transfer (dive on braking, and lift on acceleration) is to use stiffer springs.

sway bars and springs will help with the yaw i.e. side to side weight transfer, and keep the car's attitude flatter throughout the turn.

higher tire pressures will only make the tire stiffer and increase it's resistance to rolling onto the shoulder, causing additional wear. the drawback to this will be reduced grip, simply because there will be less friction between the tire and the road due to a reduced contact patch, and reduced rolling resistance.

i think that you're on the right track with springs (struts too) and swaybars.

MZM

Please look at my new post with picture. And thanks for the input.

dropkick_muppet writes:
stiffer/larger diameter sway bars are not going to help your fore/aft weight transfer issue.

I am not sure about your opinion about the rear bar. If the bar will help control side to side weight transfer, as we agree on, wouldn't it also reduce transfer toward the front too? By keeping the diagnal tire (rr) and suspension from lifting so much there is less trasferred to the lf tire. Do you disagree?

Also, is replacing the front struts necassary or just the STi spring kit? It is better of course but a lot more $$. Maybe springs are a better cost/benefit. I don't know. Anyone have experience doing this?

MM

dropkick_muppet

iTrader: (4)

gotcha, i saw the new post with pics. nice tires

you make a good point here, i was thinking more about the dynamics of the car under braking. obviously the more tires you have in contact with the ground, the more evenly the weight of the car is going to be dispersed. i'm not sure how much this will help the weight transfer on the front. it will help, it's realy just a question of whether or not it makes a noticable differance. i would think that a front sway bar in addition to the rear would help too, simply by reducing body roll/weight transfer in the front and the rear.

did you find yourself lifting the right rear a lot during your track time?

in the photo in the other thread you posted, i saw the STi badge on the back of your car. are you driving an '04 STi? if that's the case, i wouldn't worry about replacing any of your struts, unless you went to full coilovers. you can throw on stiffer springs, and the stock STi struts should be fine. Ralli Spec sells both STi lowering springs, and STi tarmac springs, which are frighteningly stiff, the latter of which would be sweet at Willow i'd imagine.

MZM

Thx for the Ralli Spec lead. I will check there. Yes, a MY04 STi. Until the tires went, the car was more than competative. I was able to catch and pass a S2000 and a turbo Porsche 914 (not to sure of various Porsche models) as well as everyone else. There was a yellow EVO there that was modded. He was faster by a small margin.

MM

dropkick_muppet

iTrader: (4)

not a problem. the STi lowering springs probably won't be too bad on the street, but the tarmac springs won't be really street friendly.