Mountain Bike Suspension on the E30

The blog has been idle for a few months, but not because of a lack of content. I've spent my free time lately writing short stories in the hopes of getting something published. The following is an excerpt of a concept all to familiar to the automotive enthusiast - too many cars, not enough money.

I got my first mountain bike in 1997. It was a matte black with natural white rubber colored tires. The seven hundred dollar bike was a massive financial commitment for a basement-dwelling college student. Working as a stagehand, I endured days of B-grade country music at a local festival to foot the bill. Within a year I found myself at my first race, the 24 Hours of Donner Pass, high in the Sierra Nevada Mountains. Over the next decade my mountain bike racing ebbed and flowed with school, work, and life.

In the mid-2000's, the 29'er movement swept the mountain biking scene. A 29'er is a bike with twenty-nine inch wheels instead of the twenty-six inch industry standard. It has a taller tire that provides some degree of suspension. This is further aided by tubeless tires, which can be run at lower pressures. Such technology made it possible to have a hard-tail bike (one with no rear shock) that was capable of being fast over rough trails. The job of soaking up the bumps is done largely by the tires, not the shocks. I've since retired from racing, but the tall tire theme remains.

When I bought my 1989 325i (lovingly referred to as the E30) it came with stock fourteen-inch bottle cap wheels and snow tires. These were great for Colorado's winter months, but summer required something that gripped and looked better. I found a set of seventeen inch BBS RGR wheels in four lug fitment and wrapped them with 215/45 sized rubber purchased in a questionable transaction behind a local grocery store. On the stock suspension, the seventeen-inch wheels made the E30 look like a skateboard. Rather than admit that seventeen-inch wheels are just too big for an E30, I lowered it on a very used set of sport shocks and springs.

The contact patch of 215 sized tires on firm shocks allowed the E30 to corner with impunity, but the ride was worse than square wheels on a wooden roller coaster. The gashed, cratered, and comically torn asphalt of Colorado's roads didn't help matters. My daily commute was a few exhilarating turns separated by a litany of trauma. One spleen-rupturing bump at a time, I slowly became a believer in Mike Miller’s logic that large wheels aren't always better. Last fall when a bridge gap transformed the light in my map light mirror into a tooth-chipping projectile, I decided that enough was enough.

The proper solution would be to upgrade my very used shocks with a set of Koni's better suited for a lowered suspension. You really do get what you pay for with shocks, and my experience with Koni-based suspensions has been wonderful. Unfortunately, the recent acquisition of a track car rendered such a solution financially impossible. BBS wheels are generally a precious metal investment as stable as gold, perhaps I could sell them and find a suitable set of smaller replacements. It took a few months, but I ultimately worked out a deal for a set of black fifteen-inch E34 M5 throwing star replicas. Mounted on an E30 some could view such a choice as scandalous, but at least they are period correct and more importantly allow a taller tire.

The track car had also sapped money for tires, but judicious use of a Costco credit card enabled enough reward points for a free set. After months of creative scheming, my spleen would finally arrive to work unbruised. When I kindly strolled into the Tire Center and asked for a set of "205/55 R15's in the highest performing rubber you got" my hopes were shunted. Costco caters to the all-season, big-wheeled, crossover driving masses. The closest thing they had were 195/60 R15 all-season tires. For those unclear on tire sizing conventions, a 195/60 is a taller, narrower tire than a 205/55. The fact that they only had all-seasons prompted me into an unsolicited and rather lengthy lecture on the superiority of dedicated winter and summer tires. My dissertation was received apathetically by the texting soccer moms in the waiting room and with outright distain by the girl behind the counter. With the BBS wheels long gone, no money, and the need to drive to work I was left with no other option. All seasons it would be, and tall ones at that!

Seeing the positive, I rationalized that the E30's ride would be even smoother on taller tires. The new setup definitely made it smoother, but it was ass-backwards. High profile tires and firm shocks, rather than low profile tires and compliant shocks. When pushed hard the flexi sidewalls make my new tires howl like a canine acapella quartet. The ride is just like my 29'er hard-tail mountain bike, smooth over small bumps, harsh over big ones. To ride such a bike at race speed requires a surgical line through the trail, driving the E30 now demands a similar level of precision between craters. My thirty mile commute is now a racecourse of bumps, gaps, gashes, and potholes, all of which I have memorized. Who knew all those years of mountain biking would pay off in my daily commute!

Yesterday in an attempt to avoid school work I gave the E30 a thorough detailing. Both power and hand washings, a full clay bar treatment, and two coats of wax did little hide the scars of 230,000 daily driven miles. As is often a misconception with humans, beauty is not found in perfection. The blemishes and imperfections can be beautiful. The beauty of the E30 lies in everything that it is not. A new, modern car may look perfect, but it is probably bigger, heavier, and littered with driver aids. The E30 is blissfully simple, honestly communicating the road to its driver through exceptional balance and rear wheel drive. It is the original Ultimate Driving Machine. A machine that helped define a brand that has wandered far from its roots. If I could only keep one car, it would be the E30. It's not the fastest or the flashiest, but it's the most fun on the way to work.