Oversteer vs Understeer: Which is better? (DriveTribe Article)

[BmacIL]

The CG did move rearward, but I don't think that the amount it moved could be by enough to matter. I'm seeing 46.0% rear weight become something like 46.05% (gaining around 2 lbs) - it's a side view geometric solution involving fairly shallow triangles and arcs drawn about the front stub axle.

It's easy to assume that changes in the relation between front and rear ride height are due to "weight" moving around, but we know that didn't happen. The sprung mass just rotated slightly about the front axle.


Norm

It is small but with a sticky tire and quite stiff suspension (2 Hz range), I suspect you may feel it. I actually ran the calculation at one point for the effect of lowering the front ~0.3" and it was definitely far more than just a few pounds, though still only in the tenths of % Wt Dist.

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[Bluemustang]

I prefer close to neutral. Only getting a bit of oversteer with a heavier provocation of throttle. An overt or easily accessible oversteer leads to some oh shit moments. An easier way to wreck your car especially if your driving that way on the street.

The reason the stock cars understeer is the MacPherson strut suspension. You need more negative camber up front, stiffer springs and a stiffer bar to keep the front geometry in check. Doing that plus modifying the alignment settings and tire setup is a good way to dial it imo without needing a stiffer rear sway bar. Enough power from the rear wheels to get the rear end to step out if you want it to.

https://oppositelock.kinja.com/why-your-bmw-needs-a-front-swaybar-1733925447

This article kind of explains what is happening with the MacPherson strut suspension up front. Keeping the front end flat while keeping the camber curve in check will help reduce understeer.

 

[Roadway 5.0]

I prefer close to neutral. Only getting a bit of oversteer with a heavier provocation of throttle. An overt or easily accessible oversteer leads to some oh shit moments. An easier way to wreck your car especially if your driving that way on the street.

The reason the stock cars understeer is the MacPherson strut suspension. You need more negative camber up front, stiffer springs and a stiffer bar to keep the front geometry in check. Doing that plus modifying the alignment settings and tire setup is a good way to dial it imo without needing a stiffer rear sway bar. Enough power from the rear wheels to get the rear end to step out if you want it to.

https://oppositelock.kinja.com/why-your-bmw-needs-a-front-swaybar-1733925447

This article kind of explains what is happening with the MacPherson strut suspension up front. Keeping the front end flat while keeping the camber curve in check will help reduce understeer.

I am a stubborn mule my friend. While I agree that a proper front setup is necessary (I have more negative camber, a PP front bar, and 225lb springs), I stand tall on a stiffer rear sway bar being added to the mix is a good thing. How stiff is certainly a debate and toward driver preferences.

I had never studied into wheel rates vs swaybar rates before, and @BmacIL brought some good detail to light. My big rear sway was too much when at full stiff -- while I didn't crash nor ever slide out nor have "snap oversteer" nor have an "oh shit" moment, I did have chattering of my inside rear tire during very tight, medium throttled, inclined turns. It was too much, though I loved the razor sharp turn-in. Setting the big bar on full soft (~280) has without any doubt given me the "point and shoot" dynamic I look for in a car without any adverse effects to rear tire traction.

I will admit, though, that I strongly considered adding a slightly larger front bar. I was getting just a touch of awkward tipping from the front, but the roll center correction kit resolved this (to my surprise). Bottom line is that the car has never felt better. So good that I am, no kidding, done with suspension modifications.

 

[bootlegger]

It is small but with a sticky tire and quite stiff suspension (2 Hz range), I suspect you may feel it. I actually ran the calculation at one point for the effect of lowering the front ~0.3" and it was definitely far more than just a few pounds, though still only in the tenths of % Wt Dist.

I still haven't been able to warm these tires enough to get the most out of them. I need a track day.
Would 1/3in spacers still be safe with stock studs? With the 5mm, I had a ton of thread (7 turns maybe). I was considering leaving the 5 mm up front, going from 3 to 8.3 mm in the rear, then taking camber another half a degree negative. After that, I think it would be time for a track test.

 

[BmacIL]

I still haven't been able to warm these tires enough to get the most out of them. I need a track day.
Would 1/3in spacers still be safe with stock studs? With the 5mm, I had a ton of thread (7 turns maybe). I was considering leaving the 5 mm up front, going from 3 to 8.3 mm in the rear, then taking camber another half a degree negative. After that, I think it would be time for a track test.

5 mm is the max safe amount, and should give you approx 9-10 turns of thread engagement, corresponding to ~14 mm, which is what you want. I would not recommend more than that at all.

See how the car does when everything is warm.

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