The public needs LSDs!
Limited slip differentials belong on every car.
My car, just like nearly every other front-wheel drive car on the market today, has an open differential. Today, only select sports cars have limited slip differentials installed from the factory. They're seldom even offered as optional equipment. What gives?
My best guess is that the average car buyer does not know what a limited slip differential is or why they'd need one. Perhaps if buyers knew what they were missing, they'd appreciate the option of plunking down $500 for a proper differential alongside $1200 appearance packages.
If you don't have a limited slip differential, you have a differential that does not- as the name implies- limit slip. This "unlimited slip" differential is is called an open differential. An open differential is very simple, and it results in your engine sending its torque to the wheel with the LEAST amount of traction. Take a moment to think about that- today's powerful modern engine (many over 250hp) send all its power to the wheel with the LEAST amount of traction! It doesn't take much thought to conclude this is a very bad thing! All it takes is one wheel to slip before your entire car becomes crippled. With 250hp available, even the most aggressive tires are going to feel a bit overwhelmed. Once a tire starts slipping, its grip drops rather drastically, escalating the problem until the driver eases up on the gas pedal. Because only one wheel need lose its footing for the car to become immobilized, many automotive enthusiasts hence refer to open-differential vehicles as one-wheel drive.
In practical terms, an open-differential means that if one of your front tires is on slick ice and the other one on grippy ashphalt, your car won't go anywhere. It won't matter that the other three wheels are on asphalt- you're stuck. This embarassing moment is the very reason why many people feel more comfortable in all-wheel drive vehicles, which almost always have at least one limited slip differential. I think most drivers don't realize exactly why they're stuck, and car companies just love to take advantage of this by selling you a complex all-wheel drive system rather than a comparitavely inexpensive limited-slip upgrade.
A torsen (torque-sensing) limited slip differential sends your engine's torque to the tire with the MOST traction. One tire in your car will almost always have some traction, and a torsen limited slip will automatically maintain the delicate balance of traction between the two tires. It truly is the difference between one-wheel drive and two-wheel drive.
I think front or rear-wheel drive cars have bad reputations for snow vehicles not because of their drivetrain layout, but because the cars are built with open differentials. Two wheel drive isn't bad if you actually can use both wheels, but that dang open-differential only utilizes the wheel with the least amount of traction! Thus, the market for all-wheel drive vehicles is currently booming.
More often than not all-wheel drive is an overkill solution- and one that's not without penalties. In mass, a limited slip differential does not cost more than a few hundred dollars to build, making it far less expensive than all-wheel drive. Also unlike all-wheel drive, it doesn't take up extra space, reduce fuel economy, or add significantly to a vehicle's weight. A limited slip differential fits right where the existing differential resides, thus every car could accomodate one. And it's not just useful in snow, either. It's for wet roads or the occasional patch of loose gravel, too. Who hasn't accidentally spun a tire on a damp road when the light turned green? The benefits would be felt in every drive.
However, customers like the idea of "all wheel drive" when car shopping. More is better, right? Manufacturers have been quickly adopting all-wheel drive systems as optional equipment on their vehicles to attract more customers. Meanwhile, even those few cars built with limited slip differentials hardly advertise this fact. Despite their importance, America has historically not responded to the advertising of a limited slip differential. There is little demand (or perhaps little driver education), so manufacturers do not build them. Because manufacturers do not build them, consumers do not realize what they are missing.
Which comes first, the chicken or the egg?
My car, just like nearly every other front-wheel drive car on the market today, has an open differential. Today, only select sports cars have limited slip differentials installed from the factory. They're seldom even offered as optional equipment. What gives?
My best guess is that the average car buyer does not know what a limited slip differential is or why they'd need one. Perhaps if buyers knew what they were missing, they'd appreciate the option of plunking down $500 for a proper differential alongside $1200 appearance packages.
If you don't have a limited slip differential, you have a differential that does not- as the name implies- limit slip. This "unlimited slip" differential is is called an open differential. An open differential is very simple, and it results in your engine sending its torque to the wheel with the LEAST amount of traction. Take a moment to think about that- today's powerful modern engine (many over 250hp) send all its power to the wheel with the LEAST amount of traction! It doesn't take much thought to conclude this is a very bad thing! All it takes is one wheel to slip before your entire car becomes crippled. With 250hp available, even the most aggressive tires are going to feel a bit overwhelmed. Once a tire starts slipping, its grip drops rather drastically, escalating the problem until the driver eases up on the gas pedal. Because only one wheel need lose its footing for the car to become immobilized, many automotive enthusiasts hence refer to open-differential vehicles as one-wheel drive.
In practical terms, an open-differential means that if one of your front tires is on slick ice and the other one on grippy ashphalt, your car won't go anywhere. It won't matter that the other three wheels are on asphalt- you're stuck. This embarassing moment is the very reason why many people feel more comfortable in all-wheel drive vehicles, which almost always have at least one limited slip differential. I think most drivers don't realize exactly why they're stuck, and car companies just love to take advantage of this by selling you a complex all-wheel drive system rather than a comparitavely inexpensive limited-slip upgrade.
A torsen (torque-sensing) limited slip differential sends your engine's torque to the tire with the MOST traction. One tire in your car will almost always have some traction, and a torsen limited slip will automatically maintain the delicate balance of traction between the two tires. It truly is the difference between one-wheel drive and two-wheel drive.
I think front or rear-wheel drive cars have bad reputations for snow vehicles not because of their drivetrain layout, but because the cars are built with open differentials. Two wheel drive isn't bad if you actually can use both wheels, but that dang open-differential only utilizes the wheel with the least amount of traction! Thus, the market for all-wheel drive vehicles is currently booming.
More often than not all-wheel drive is an overkill solution- and one that's not without penalties. In mass, a limited slip differential does not cost more than a few hundred dollars to build, making it far less expensive than all-wheel drive. Also unlike all-wheel drive, it doesn't take up extra space, reduce fuel economy, or add significantly to a vehicle's weight. A limited slip differential fits right where the existing differential resides, thus every car could accomodate one. And it's not just useful in snow, either. It's for wet roads or the occasional patch of loose gravel, too. Who hasn't accidentally spun a tire on a damp road when the light turned green? The benefits would be felt in every drive.
However, customers like the idea of "all wheel drive" when car shopping. More is better, right? Manufacturers have been quickly adopting all-wheel drive systems as optional equipment on their vehicles to attract more customers. Meanwhile, even those few cars built with limited slip differentials hardly advertise this fact. Despite their importance, America has historically not responded to the advertising of a limited slip differential. There is little demand (or perhaps little driver education), so manufacturers do not build them. Because manufacturers do not build them, consumers do not realize what they are missing.
Which comes first, the chicken or the egg?
posted by Steve at
8:02 AM
1 Comments:
Steve, you are echoing many of the sentiments I feel about the US automobile market in your blog. I worked as a grease monkey for a while in my college days and saw so many vehicles with 4WD/AWD that were just doubling or tripling the lube change cost and providing virtually no benefit. My old VW Fox was almost unstoppable in snow, etc (and I delivered morning newpapers in it in all kinds of weather). It was barely more than a FWD econobox but I loved it. Ever since that lube tech job I swore I would never waste all that $ on a street vehicle with the extra gearboxes and transfer cases that make up the guts of a 4WD system. Now your LSD comment here has some value to me as I will be soon purchasing a 1st gen Mini Cooper S convertible. I am buying used and cannot wait for a perfect match to come along. So I am looking for an LSD equipped car (but I cannot make it a dealbreaker item).
Cheers,
Andrew
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Unknown, at 5:10 PM
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