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Originally Posted by M3SQRD
I’m curious. You don’t believe there are proper front and rear ride heights? Angled upward (above horizontal) control arms perform fine?
Running excessive forward rake alters the steady-state balance of the e9x M. Zero finger gaps front and rear is far from ideal for the track and is not close to a proper corner balanced car + cross weights. A properly corner balanced car has minimal forward rake. My two corner balanced + cross weighed e92 M3s fall within the 3/8-7/16” forward rake recommendation at 0.42” and 0.41”.
A corner balanced + cross weighed f82 has a forward rake that falls between the 0.40-0.50” forward rake recommended range. My f82 forward rake is 0.46” which falls within the recommended forward rake range.
This is not directed at you. The handling characteristics of a car properly corner balanced and cross weighed are so much better than a non-corner balanced car or a car with excessive forward rake to match front and rear tire-to-fender gaps. However, form over function is widely used by both track and stance groups. Track groups that upgrade to 2-3 way adjustable dampers, adjustable anti-sway bars and adjustable drop links, full monoball suspension arms, precise suspension alignments yet they completely ignore corner balancing and/or run excessive forward rake primarily for looks, not performance, doesn’t make sense to me. You’d get more handling performance out of your car by just properly corner balance than converting all suspension arms to adjustable monoball arms.
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To answer your question, yeah, I think there’s definitely an ideal front and rear ride height for optimal handling. Too much forward rake can mess with the balance of the E9X M3 in steady-state cornering and braking. That said, a little forward rake—something in the 0.3–0.5” range—can help with weight transfer under braking and improve overall grip.
From my experience, running excessive forward rake absolutely killed my braking performance. (To be fair, this was right after I installed coilovers and hadn’t dialed them in before the shakedown.) It overloaded the front tires and made the car feel sketchy under heavy braking. When I switched to a more neutral rake, braking performance improved, and the car felt much more balanced overall. For track setups, a slight forward rake combined with solid corner balancing can really tie the suspension and handling together. But honestly, matching tire-to-fender gaps front and rear just for looks is more of a "stance" move and not something I focus on for performance.
Now, about corner balancing—this might be an unpopular opinion, but I don’t think it’s that important for the average HPDE driver. If you’re out there just to have fun, there are so many variables that can mess with your left-right and x-weight distribution anyway. Things like fuel level, passengers for laps, and other things. For example, if you corner balance with a full tank and then burn through most of your fuel, your balance is already off. Same goes if you set it up solo and then take a passenger along. So, stressing about "perfect" corner weights feels overkill unless you’re chasing lap times or running in a competitive environment.
That said, corner balancing does have its benefits. It makes the car more predictable and consistent by evenly distributing weight across all four tires, which can give you more confidence behind the wheel. But honestly, it’s not some magic fix for handling. As long as your alignment, suspension, and geometry are dialed in, you’ll be fine without obsessing over corner weights—at least in my opinion.
One other thing I wanted to throw in: bump stops. They don’t get a lot of attention, but some people swear the E9X M3 performs better when it’s slightly riding the bump stops. The idea is that they act like a progressive spring rate when you’re pushing the car hard. Personally, I don’t really follow that principle, but I do use a floor jack to simulate full compression and check if there’s enough suspension travel when the tire tucks under the fender/quarter panel to avoid bottoming out over curbs, dips, elevation transitions, etc...which is why I recommended that earlier when setting ride height.
Maybe one day I’ll fix my rake and get everything properly sorted. But honestly, I haven’t even been to a track day in 2024, so it’s not at the top of my list right now.