Here's What Subaru Symmetrical All-Wheel Drive Really Means

When it comes to rally heritage, few automakers carry the same prestige as Subaru. The Japan-based company won World Rally Championship (WRC) titles six times; three Driver's Championships and three Manufacturer's Championships. You don't win something as difficult as a WRC title without having some serious cars packing second-to-none technology backing you up, and that's exactly what Subaru had.

Among the litany of racing-bred innovations found on today's road cars, such as disc brakes, turbochargers, and the semi-automatic gearbox sits all-wheel drive. The first all-wheel drive system was incorporated into a rally car by Audi on their Quattro, but once Subaru introduced their all-wheel drive system, the game was changed forever.

The Rise Of Subaru's Symmetrical All-Wheel Drive

Symmetrical All-Wheel Drive Quick Facts

• First used in 1972 in the Subaru Leone Wagon
• Nearly all Subarus built since 1986 have featured Symmetrical All-Wheel Drive
• While more technologically-capable, the Symmetrical All-Wheel Drive system uses fewer parts than competitors

While Subaru's affinity for including its Symmetrical All-Wheel Drive (SAWD) system on virtually all of its vehicles began in 1986, the first rudimentary version of the system was first seen in 1972. It was a full-time all-wheel drive configuration, meaning power was constantly sent to all four wheels simultaneously. However, the difference seen in the early SAWD system over competitors' systems such as the one found on the Jenson FF became apparent in the corners.

Over the next 13 years following the Leone Wagon's release, Subaru used their SAWD system on a select few models, including the aforementioned Leone Wagon and the Subaru Bi-drive Recreational All-terrain Transporter, or BRAT for short. Then came 1986 and the introduction of the Subaru XT, a small sports car featuring the brand's first full-time, push-button SAWD system.

The Legacy's Mark Is Still Felt Today

The introduction of the Subaru Legacy in 1989 cemented Subaru's place as a dominant automaker around the world. The Legacy was much more conventional in its styling, as Subaru had been known as a bit left-field before it. The Legacy's job was to make consumers take Subaru more seriously, and also debut its SAWD system to the mass-market four-door sedan world, something other automakers hadn't done on a massive scale. The Legacy was a resounding success for the company.

Today, Subaru can thank the Legacy for bringing the company into the forefront of all-wheel drive mass-market domination. Of course, things didn't stop there. The SAWD system was raced and honed on the world's toughest rally stages throughout the late 1980s, 1990s, and early 2000s before Subaru's eventual withdrawal from the WRC. The current Subaru WRX continues the SAWD tradition, although the new system is vastly different from that first implementation seen 52 years ago.

How SAWD Works, And What It Does Better

When the 1972 Subaru Leone Wagon found itself in a slippery situation around a bend, the SAWD system was able to send power to each wheel individually thanks to a clever center differential. The inclusion of this center diff meant each wheel would automatically be provided with the right amount of thrust to get through the slippery corner best. In other words, the wheels with the most grip received the most power, and vice versa.

Conventional AWD systems seen in the old days consisted of two differentials with a constant amount of thrust provided to each wheel, and the systems were unable to split power independently like Subaru's system could. Today, the SAWD's ability to independently split the vehicle's power to each individual wheel is still the system's party piece, and allows for vehicles like the outgoing Subaru Legacy to grip better than virtually any other inexpensive, mass-market sedan when faced with adverse driving conditions. It's also a full-time all-wheel drive system, which means power is always going to the front and rear axle, and neither is shut down to save fuel. Another SAWD party piece is the weight distribution of the car. Because all Subies use a low-mounted boxer engine, its cars have a low center of gravity for improved handling. The weight of the various components is also distributed evenly among the platforms.

As we mentioned before, other AWD systems couldn't offer this sort of grip in the early days. When SAWD was finally installed on the mass-market and very conventional Subaru Legacy in 1989, Subie had the market to itself, and people quickly began to see the benefits of an all-wheel drive car, especially those who lived in areas with snowy winters or muddy roads. When we see the litany of sedans and coupes on the roads today boasting AWD badges, we have Subaru to largely thank for that.

How SAWD Dominated Rally Racing

It may not come as a surprise to learn Subaru's SAWD system was integral in its World Rally Championship successes. Its first win came in 1994 at the Acropolis rally attached to the Subaru Impreza WRC rally car. However, the Subaru rally team's first WRC championship would come a year later, in 1995, when the Subaru 555 team won both the manufacturer's championship and the Driver's Championship, with Colin McRae being the driver to score the win.

The SAWD system came into its own in rally racing. Because of its ability to selectively provide power to whichever wheel or wheels had the most grip, the rally stages saw the Subaru WRC car flick around corners faster than anything they'd seen before. Another great aspect of the SAWD system with regard to motorsport is its simplicity of design. When the system breaks or requires a repair, it's a relatively simple fix compared to other systems such as Audi's complicated, but still impressive, quattro system.

As time went on and Subaru became heavily involved in honing and fine-tuning their Impreza WRC car and their SAWD system, the Japanese brand won an additional five WRC championships, the last of which would come in 2003.

The SAWD System Is The Jack Of All Trades

As a culture, the automotive world takes all-wheel drive for granted these days. Virtually every model offers some sort of all-wheel drive system. You can buy small hatchbacks like the Mazda3 that will come with AWD, and even tons of sports cars come with the system these days, a segment where rear-wheel drive used to dominate.

Like we said earlier, Subaru is mostly the one we can thank for all-wheel drive's extreme commonality in today's world. If it wasn't for their keen willingness to think outside the box with their original 1972 system and their tenacity when it came to constantly improving the SAWD system through both motorsport and civilian motoring, we wouldn't be able to drive our mass-market AWD cars through snowstorms and along beaches without worry.