Correct Understeer

[GaryRudolph]

Anyone changed the front/rear width to compensate for the understeer? I'm now debating doing a 275 front, 285 rear. Or has anyone found any replacement front sway bars? I'll probably play with the tire pressures and alignment as well, but I'm not expecting a tremendous amount of benefit with that as it's a significant understeer.

I'd like to get it to at least have power on oversteer.

[AriciU]

Wouldn't you get more understeer by increasing the front tires width? Seems logical too me. Skinnier tires on the front will break the rearend loose more easy IMO.

[GaryRudolph]

No, to correct understeer you need to get more traction on the front wheels and less traction on the rear. What reduces traction on the front is tire lifting the inside edge off the pavement.

The options to fix this are (probably a combination of all):
1) Stiffer suspension to reduce roll to reduce the tire from lifting on the inside edge.
2) Stiffer swaybar to reduce roll to reduce the tire from lifting on the inside edge.
3) Increase camber so that when the car rolls the tire is flat to the pavement.
4) Increase the width of the front tire. Although, I'm now thinking that the previous 3 will help more.

On the M3 forums to combat the understeer they are doing a combination of all three, and some are running the same width tires all around.

[Nick325xiT 5spd]

Wouldn't you get more understeer by increasing the front tires width? Seems logical too me. Skinnier tires on the front will break the rearend loose more easy IMO.
WTF are you talking about? Do yourself a favor and do a lot of research before you ever speak of handling again.

Combating understeer with a BMW runs in this order:
1) More negative camber.
2) More front tire.
3) Bigger front bar.

Power on oversteer is just tough to get when you've got an open diff.

[650iOzBoy]

2) Stiffer swaybar to reduce roll to reduce the tire from lifting on the inside edge.


Does the Dynamic Drive option (active anti-body roll) function help in your point no.2?

[Nick325xiT 5spd]

Does the Dynamic Drive option (active anti-body roll) function help in your point no.2?
Yes. These cars don't suffer from viciously uncontrolled body roll like, say, the E46 M3 does.

[GaryRudolph]

Combating understeer with a BMW runs in this order:
1) More negative camber.
2) More front tire.
3) Bigger front bar.

Decided to do some alignment work to see if I could help it and then try tires. Holding off on a tire/wheel order to see how different alignment settings work.

Power on oversteer is just tough to get when you've got an open diff.
Yah, surprised when I bought the car it was an open diff... For some reason I didn't even think about and just assumed it was limited slip, torsen or something (for the price). Already I get a lot of inner tire spin on canyon roads.

Took a bit of work to get my S2000 to where I wanted it. I guess this will be no different.