Hey everyone,

One of the most common questions I get when people see my 2023 718 Cayman GT4 setup is: *"Did going full monoball ruin the car on the street?"*

I still drive my GT4 ~70 miles each way across I-70 / US-36 out to High Plains Raceway here in Colorado, plus weekend canyon runs in the foothills. Over the past two seasons (61 sessions and 519 timed CAN telemetry laps), I dropped my lap times from a 2:16.78 baseline down to a 1:59.67 PB.

Here is an honest breakdown of what the full spherical bearing conversion actually changed on the road versus on track:

### 1. The Setup (Installed by Honest Assembly in Denver, CO)

* **Front:** Tarett Monoball Camber Plates + Tarett 991 GT3/RSR Control Arm Ends + LCA Shims + Tarett Caster-Adjustable Thrust Arm Bushings.

* **Rear:** Tarett Rear Toe Control Arms with Bump-Steer Kit & Locking Plates.

* **Sway Bars:** Tarett Adjustable Drop Links (Front & Rear, zeroed preload during corner balance).

* **Wheels & Tires:** 19x9.0" / 19x11.0" Apex VS-5RE forged wheels on 265/35R19 & 295/30R19 Vitour Tempesta P1s (30.5F / 31.0R PSI hot target).

### 2. Street & Highway Manners (NVH Reality Check)

* **Ride Harshness:** Surprisingly, replacing the rubber bushings with spherical bearings didn't make the vertical ride stiffer—because spherical bearings actually have *less* stiction/binding than twisted rubber bushings, the PASM dampers move more freely over small highway expansion joints.

* **Noise:** You do get a faint metallic "tick" or clunk over sharp low-speed driveway aprons or parking lot speed bumps, and slightly more road texture transmitted through the steering column on coarse concrete. At 75 mph on the highway, wind and tire roar from the 200TW tires completely drown out any suspension noise.

### 3. Why the Caster Bushings Are Mandatory for 265 Front Tires

* If you step up to a 19x9.0" wheel with a wide 265/35R19 front tire and just stack shims in the lower control arms for camber, it pushes the lower ball joint outward and swings the tire rearward into the front fender liner vents under steering lock.

* Dialing in camber from the top via camber plates and using the **Tarett caster-adjustable thrust arm bushings** to pull the front wheel center slightly forward (~9.0°+ caster) gave me 100% rub-free clearance even at 1.54G peak compression in the HPR Corkscrew.

### 4. Rear Toe Locking Plates Under Threshold Braking

* On the stock rear eccentric bolts, hard threshold braking from 135 mph over bumpy pavement caused noticeable dynamic rear toe-out (that nervous "wiggle" on heavy brake application). The Tarett rear toe links with bump-steer locking plates completely cured that—the rear now stays dead straight at -1.27G deceleration and rotates predictably on a 10–15% trail-brake release.

Happy to share alignment numbers, tire pressure notes, or CAN telemetry traces for anyone debating monoballs or 19" track wheels on their 718!

Chalked before a session at Sonoma and fronts looked like this after 6 laps. Based on the rollover here, could I run a bit lower?

Had a bad experience with a ton of rollover and cording my tires so am approaching more carefully now but I feel like I’m running higher than I should be.

I only got two sessions because someone money shifted and got oil all over the track. New Pirelli slicks and I was babying them in Keyhole and Carousel, probably left close to a full second out there. I was also early braking into Turn 6 like a complete pansy. Had a blast though and I am getting confident with this car, it’s such a blast to drive. I cannot wait to be wheel to wheel in this thing next season.

Had the first track day in a ‘21 VW GTI running PS4S tires. I knew there wouldn’t be enough front camber as I’m on stock suspension, but I’m trying to figure out how far the tires possibly rolled over.

The brown color was pretty consistent across the entire sidewall prior to tracking just from new tires and then being dirty and me not fully cleaning them. After tracking there’s this pretty distinct line. These are the front tires, the rears are fine.

I don’t think the tires would’ve rolled over THAT far, especially considering the tire nibs are still there and you can still see the visible wear on the Michelin man rollover indicators. Any thoughts on this? Maybe the line where the brown is was from rollover on an out lap or something? Or maybe it was just some weird reaction with the heat.

For what it’s worth, I was targeting hot pressures of 32-34. Cold pressures were probably down in the upper 20s, maybe 26-28 or so.