Anyone who says regulations stifle innovation clearly knows little about business compared to motorsport. Necessity is the mother of invention, and every rule created to slow cars has been brilliantly twisted, exploited, and circumvented in ways that have only passed into legend—or remained secret until recently. One of the lesser-known rules was implemented by BMW, which implemented a new “pendulum brake” to gain an edge in Super Touring. But as clever as it is, it’s an invention that just might help kill off this legendary racing category.
The 1990s could be said to be the heyday of touring cars, and one of the most popular categories was Super Touring. Based on the 2.0-litre class of the British Touring Car Championship, Super Touring cars replaced Group A in circuit racing around the world starting in 1992. According to the Super Touring Register, BMW was on board from the start with its new 3 Series, the E36, which it wanted to build on the E30’s pedigree. However success was limited, with early chassis winning some smaller regional championships, but not in countries with the most competitive fields. What BMW needed was an edge over the competition, and apparently, McLaren had the answer.
1997 BMW E36 Super Touring. Live Racing Cars
According to an old sales listing for the E36 Super Touring on Race Cars Direct, BMW Motorsport asked McLaren to upgrade the car in 1997. It’s unclear what McLaren did to improve the car, with the suspension being the only part specified in the listing. advertisement. But it would have been a strange coincidence if McLaren had not had a hand in the new “pendulum brake” of the ’97 Super Touring E36, not with what was happening at the Formula 1 team that year.
You may remember 1997 as the year of the “violin brake” controversy. In short, McLaren installed an extra brake pedal to retract the inside rear wheel, which significantly improves agility and stability. This would eventually be banned, but a similar idea may have invaded the E36 program, whose pendulum brakes were a little more complicated.
The function of the pendulum brake is outlined in the Schnitzer Classic video, which supports the old race cars of Schnitzer Motorsport, the historic BMW racing team that campaigned this E36. Under the dashboard, there is a proportional valve that regulates the brake balance which is inserted into the front brake hydraulic line. Normally this is only used to adjust fore-aft bias, but here the adjustment is lateral and controlled by a pendulum swinging from side to side. When the driver turns the steering wheel, the pendulum swings outward, directing more braking force to the outside wheel than the inside wheel.
This may sound counterintuitive if you know how modern torque vectoring works; often protracted in the wheels to eliminate understeer, not the outer ones. Many commentators reacted in the same way, believing that pendulum brakes would make braking in corners impossible. But as kart racer Javier Fichera pointed out in his comments, the rotation would shift the load to the outside wheel. We’ve all seen cars lock up the inside wheel when braking into a corner, and in the absence of ABS (which Super Touring forbids), this system is designed to prevent that.
However, you may wonder why the proportional valve isn’t mounted directly to the steering column for quicker response. This is just speculation on my part, but lag is the crux of the pendulum: Lateral brake bias changes in sync with load shift, not in front of it. The brake balance only changes when there is a handle to use it.
So how did it go? Well, looking at the career of the ’97 E36 Super Touring chassis onwards, it appears that the upgraded E36 was significantly more competitive from the start. However, its power would be limited because in December 1997, BMW replaced the E36 with the E46. It’s also nearing the end of the Super Touring peak, as 1990sBTCC.com editor Alex Clarke explained to Drive. In addition to brand politics as brands acquire each other, costs get out of control and cause manufacturers to pull out—of course, due in part to tricks like BMW’s pendulum brake.
But successful or not, new ideas are the lifeblood of motorsport. Win with them, and you will change the game. Failing that, at least you’ll give others something to talk about—and keep you in mind, no matter where you finish.
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