When you’re deciding between a limited slip differential (LSD) and an open differential for street use, it’s good to know how each will change your car’s handling. An LSD helps you hang onto traction while cornering by shifting power to the wheel that’s gripping, while an open differential just sends power to whatever wheel spins easiest, which isn’t always ideal.
For daily driving, an open differential keeps things simple and predictable. It’s smooth and stable on regular roads.
If you want more grip in rain or on rough pavement, an LSD gives you that extra control. The trade-off? It might feel a little rougher in tight turns.
Your decision really comes down to what you want out of your car. LSDs can boost cornering and traction, but they might wear out your tires faster and need more upkeep.
Open diffs are usually easier to maintain and give a comfy, dependable ride on most streets.
Key Takeways
- LSDs boost traction in corners by sending power to the wheel that’s got grip.
- Open differentials are smooth and predictable for everyday use.
- LSDs might need more maintenance, but they’re great for tricky roads.
Fundamentals of LSD and Open Differentials
Knowing how differentials work helps you understand how your car puts power down. Each type has its own way of handling traction and power, which shows up in how your car feels—especially on city streets.
How Open Differentials Work
An open differential splits engine torque evenly between the two wheels on an axle. Each wheel can spin at a different speed, which is handy for turning.
The catch is, when one wheel loses grip, the open diff keeps sending power to it. That can mean trouble on slippery or uneven roads.
Open diffs are straightforward and tough, with hardly any maintenance needed. They’re great for daily driving, but not when you need serious traction.
The driveshaft sends power through the differential to both wheels, but it doesn’t pick favorites.
How Limited Slip Differentials Operate
A limited slip differential (LSD) steps in when one wheel starts spinning. It sends more torque to the wheel with grip, keeping you steadier.
There are a bunch of LSD types. Mechanical ones use a clutch pack to shift torque between wheels. Torsen and Quaife LSDs use gears to automatically balance power.
Viscous LSDs work with a special fluid that thickens as wheel speed differences increase. They’re smooth, but not the fastest to react.
LSDs let you get on the gas earlier out of a corner and help on slick streets. They keep the wheels spinning closer together in speed, so you don’t get that wild free-spinning you sometimes see with open diffs.
Key Mechanical Differences
| Feature | Open Differential | Limited Slip Differential |
|---|---|---|
| Power Distribution | Transfers power to weaker wheel | Transfers more power to wheel with traction |
| Wheel Speed Difference | Freely allows | Limits excessive difference |
| Key Components | Simple gears | Clutch pack, viscous fluid, or gears (Torsen) |
| Reaction to Slip | No traction control | Engages to reduce wheelspin |
| Maintenance | Low | Greater due to clutch wear or fluids |
LSDs are more complicated, with extra parts to handle torque. The one you pick really changes how your car behaves when things get slippery.
Pros and Cons for Street Use
When you’re picking between an LSD and an open diff for a street car, there are some real-world trade-offs to think about. How each one handles traction, weather, and comfort can make or break your daily drive.
Traction and Everyday Grip
LSDs send power to the wheel with more grip, helping you out when one wheel slips. That’s a big deal on wet or bumpy roads.
Open diffs split torque evenly but can get tripped up on ice or snow. The wheel with less grip can just spin, and you’re left with less power.
For daily drives, LSDs help with quick starts and mild traction loss. If your roads are dry and flat, though, an open diff does just fine.
Handling and Cornering Characteristics
With an LSD, you can get on the throttle earlier coming out of corners. It sends power to the outside wheel, which usually has more grip when the car leans.
Open diffs let the rear wheels spin at different speeds, which feels smooth but not aggressive. The inside wheel can spin under power, cutting your cornering speed.
In front-wheel-drive cars, the effect is smaller. In rear-wheel-drive cars, though, an LSD really sharpens up your cornering.
Driving in Adverse Weather Conditions
In snow, rain, or ice, LSDs stop one wheel from spinning out and losing all your power. That’s a confidence boost when you’re trying to get moving or climbing a slick hill.
Open diffs tend to send power to the wheel with less grip, which can leave you stuck. But they can also feel smoother when you need gentle, careful control.
If you live somewhere with a lot of bad weather, an LSD is usually the better bet. Just watch out—on ice, it can grab suddenly if you’re not careful.
Noise, Vibration, and Comfort
Open diffs are quiet and smooth since the wheels can spin as they want. That makes for a comfy, peaceful ride.
LSDs, especially the clutch or mechanical ones, can make noise or chatter a bit in slow turns. Helical LSDs like Torsens are quieter, but they’re pricier.
If you’re doing lots of tight turns or parking, open diffs feel less intrusive. On the highway, the little bit of noise from an LSD is barely noticeable and might be worth it for the performance.
Performance Considerations and Technology Types
How your differential handles torque and power changes your car’s street and track performance. Different LSD designs use their own tricks to manage torque, which affects how your car feels in corners and when you’re on the gas.
Torque Distribution and Transfer
Every differential splits torque between the wheels. With an open diff, both wheels get equal torque—unless one loses traction, then it just spins.
LSDs fix this by pushing more torque to the grippy wheel. The torque bias ratio (TBR) tells you how much more torque goes to the wheel with grip. Higher TBR? More traction coming out of corners.
If you’re driving a rear-wheel-drive car like a Miata or GT3, an LSD lets you get on the throttle sooner and stay planted on twisty roads.
Types of Limited Slip Differentials
There’s a bunch of LSD types out there:
- Clutch pack LSDs use friction plates to limit spin. They can jerk a bit but are consistent.
- Torsen (torque-sensing) diffs use gears and ramps to shift torque, with no clutches to wear out.
- Viscous LSDs use a special fluid that thickens as wheels spin at different speeds, but they’re slower to react.
- ATB (automatic torque biasing) diffs, like Quaife, use helical gears for smooth torque transfer.
- VLSDs mix and match features for better tuning and balance.
Each has its own ups and downs for street use, depending on how you drive and what your car needs.
Impact on Acceleration and Power Delivery
LSDs help you launch by sending torque to the wheel that isn’t spinning, cutting down wheelspin.
Open diffs can waste power if a tire spins, which hurts acceleration—especially in rear-wheel-drive cars.
With a good LSD or Torsen, you’ll get smoother power through corners and better control. That’s a big deal for spirited driving or when the road gets sketchy.
Ramp angles in some LSDs change how quickly they react to throttle. The right LSD can make your car easier (and safer) to drive fast, especially if the road isn’t perfect.
Reliability, Maintenance, and Practicality
Thinking about LSDs and open diffs? Maintenance and longevity matter. Both have their own quirks when it comes to service and reliability.
Wear and Service Requirements
Open diffs are low-maintenance. Stick to regular gear oil changes, and you’re good. With fewer moving parts, there’s not much to worry about.
LSDs are more complicated. They’ve got clutches or gears that can wear—especially if you drive hard or hit the track. Sometimes those clutch packs or friction plates need replacing.
LSDs often need special gear oil or additives to keep everything happy. Skip that, and you might get noise or lose performance. Modern helical LSDs wear more gently than the old-school clutch types, so they’re a bit less hassle.
System Longevity and Cost
When it comes to longevity, open differentials usually stick around longer with fewer headaches. They’re straightforward and not as likely to fail because of skipped maintenance.
If you’re after something reliable and cheap to own, open diffs are honestly hard to beat.
LSDs, though, tend to hit your wallet harder right from the start. Repairs can get pricey, too.
Over time, the internal parts can wear out faster, especially if you drive hard or your traction control is always kicking in. Some folks are fine with that because LSDs offer better grip and handling.
If you’re watching your budget and want to keep things simple, open differentials just make sense. But if you crave better traction and don’t mind a little extra work (and expense) down the road, LSDs might be your thing.
