Mercedes was tired of getting their racing butts kicked in 1936… The W25 racer that year had a flexing chassis coupled with stiff suspension that caused the rear axle to bend 3 to 4 inches under hard braking. It made decent power, but the car just couldn’t hook up and make any traction. 1937 would be a different story. Benz regrouped in the form of a “stinktier werks” and introduced a whole new car, now with a stiffer nickel-chrome molybdenum steel tube chassis and aluminum bodywork: The W125, a real hot rod of the racing world, equipped with a roots-supercharged 5.6 liter DOHC straight 8 making 600+ HP, yet weighing only 1700 pounds. (To put those numbers in perspective, it weighed 1000 pound less than a ’37 Ford with 6 times the horsepower!! The Benz racer had a better power to weight ratio 75 years ago than a Bugatti Veyron supercar does today.) Needless to say, the W125 was WAY ahead of it’s time, and dominated the ’37 European Grand Prix season, and crushing all opposition in it’s path. The car was know for spinning it’s tires at 120 mph, and required nerves of steel to control. For 1938 changes in the rules came down, with restrictions on engine capacities and minimum weight restrictions, and the W125 was no longer eligible for entry without major modification. Mercedes ended up building a whole new racer, the W154.
Watch the vintage footage of talented drivers like the great Rudolf Caracciola fling W125′s around the track: