Simply put, BMW's F10 M5 was designed with the 7DCT in mind. The automated gearbox is capable of ripping up and down through the gears endlessly before taking the Autobahn home at a sustained 190 mph. In sharp contrast, and whether North American enthusiasts want to admit it or not, the M5's 6MT is a Frankensteinian adaptation to the platform incapable of handling the same stress as its dual-clutch sibling – that's a fact.
Our street drive revealed more about the 6MT than we were able to ascertain on the racing circuit (it is impossible to notice subtle qualities while driving at nine-tenths, with a helmet over our head, playfully chasing other M5s). We noticed that the M5 manual gearbox rev-matches on downshift when in certain modes (just like a Nissan 370Z). It works well, and the feature likely adds life to the clutch plate itself. We also noticed how much heavier and more massive the high-performance sedan felt when we were tasked with shifting. Lastly, our tooling around the Monterey Peninsula exposed the gearing as being a bit too tall for America's low speed limits.
It isn't easy to build a manual gearbox for a daily driver sport sedan strong enough to handle 500 pound-feet of torque (that kind of insane twisting force used to be reserved for race cars) and make it last 50,000-plus miles. We expected a heavy clutch, but the hydraulically assisted pedal felt unsubstantial and springy. Sadly, those qualities made engagement feel unnatural. The gear selector is well placed, but its movement was typical BMW – a bit notchy and not entirely precise. On one positive note, the light clutch made departing from a standstill easy and shifting while on-the-fly was effortless. Yet overall, something was missing. It was our smile – the 6MT wasn't very entertaining.
We were honestly a bit deflated by our BMW experience. The M5 is an impressive four-door supercar with the 7DCT, but the 6MT erases much of its fire. The manual gearbox delivers slower acceleration, reduced fuel economy (despite what the EPA prints) and, while we might be willing to give in on the numbers a little for an enhanced connection between car and driver, our time with the manual suggests its characteristics will frustrate more drivers than it will satisfy. While our enthusiast-rich blood craves involvement, in this particular situation, it became painfully clear that the computer-controlled 7DCT is the M5's better transmission.