3J Driveline Limited Slip Differentials 

Almost every car has at least one differential in their driveline. In basic terms a differential in a 2wd car is used to manage wheel speed differences whilst taking a corner.  
Imagine a small circle inside a big circle. A lap of the smaller circle will take a lot less time to complete than a lap of the big circle. In order to complete a lap of both circles in the same time, you'd either have to go really slowly around the small circle, or really fast around the big circle.  
The same is true of the wheels on your car in a corner. As you take a corner in the inner wheel will have less distance to travel than the outer wheel and as such the inner wheel will also be turning at a lower speed. If they both had the same speed, it would not be easy to take that corner and you would have a lot of understeer as they would both be fighting to travel at the same speed and will basically want to go in a straight line. 
 
The standard "open" differential is ideal in most factory cars, but is far from ideal for getting the best out of your car. It will always transmit the same amount of torque to both wheels - ideal whilst both wheels have 100% grip as they both have 100% of the torque that the engine is delivering too them. But, put one of those wheels in a situation where it can slip - for example on some ice - if it only took a tiny amount of torque to make that wheel turn, exactly the same amount of power would be sent to the wheel that isn't on ice. Hence why you'll get one wheel spinning and one not doing anything. The same theory can be applied to cornering. As the weight of the vehicle is transferred and the tyre on the inside begins to be lifted off of the ground, the amount of engine power required to make it turn is significantly reduced and so the amount of power sent to the outside "loaded" wheel, will be exactly the same. At which point, it would't matter if you had 50bhp or 500bhp, as none of it would be getting to the wheel with any grip. 
 
To get around this an LSD can be fitted. A LSD, or limited slip diff, does as it says on the tin - limits the amount of slip of that inside wheel. It does this by essentially transferring torque directly from the housing to the side gears and thus bypassing the actually differential bevel gears. 
Whether it's by the traditional method of "clutch plates", or the more contemporary method of an additional set of bevel gears, the end result is essentially the same. 

Helical or Plate-Type LSD? 

If you want more traction and a unit that you can fit and forget, with no maintenance, a 3J Driveline Fast Road NXG torque-biasing unit is for you. It is smooth and silent in use and produces no additional noise when compared directly to a standard "open" differential. You'll notice an increase in traction (though it never fully locks) but that's all you'll notice. This is why we call it our Fast Road NXG and why it proves a popular option for road cars. In particular front-wheel drive cars. 
 
For those looking for a more aggressive differential, that can fully lock the driven wheels, a plated LSD is the unit for you. 
A 3J Driveline Plate-type LSD can be set up to perfectly suit the needs of the driver. Our expert engineers can fine tune ramp angles and pre-load to control the amount of lock, and how it's delivered, under both acceleration and braking. Because there are moving parts, it will require a degree of maintenance and servicing. It can be set up for road use but noise, slight wheel judder and lack of smoothness when turning at low speed are an inherent trait of a plated LSD. Though if set up correctly in the CWP, the 3J NXG units are quieter than many. We also have a sintered plate option to further reduce this noise. The use of recommended LSD oils will also serve to reduce this noise without effecting the operation of the differential. 
 
Our experts are happy to advise you on what's best suited to you, but feel free to read the below explanations of how each type of diff works. 
 
 
 

How Does a Plate-Type LSD Work?  

A plate type LSD is chosen for applications where the driver requires the driven wheels to lock together to some degree. The amount of lock that occurs, and the speed at which this happens can be fine-tuned in how the diff is set up.  
Under load (whether acceleration or deceleration) the cross pin rides up the ramp, which acts upon the friction plates essentially compressing them and locking either side of the differential together (which ultimately connects to your halfshafts/driveshafts). 
What's in a Plate Type LSD

RAMP ANGLES EXPLAINED 

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PRE-LOAD EXPLAINED 

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1-WAY vs 1.5-WAY vs 2-WAY 

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Our reputation for engineering and the quality of our products make us a first-choice purchase for thousands of car enthusiasts and competitors, with our ever-growing catalogue of product applications further strengthening our position within the market place. 
 
 
 

Designed and manufactured in the UK   

All of our products are designed, manufactured, produced, and built right here in the UK. The simple ethics of customer satisfaction is at the heart of 3J Driveline and when combined with our innovative design, superior products, and competitive pricing structure, we continue to deliver very happy and satisfied customers. From classic and fast road enthusiasts to club and international racing drivers across the UK, Europe, USA and the rest of the world. 

Talk to us   

We always have time to talk. So if you have a product enquiry, technical query, require aftercare or have any other questions relating to our product range both present and future, be sure to get in touch. You can be assured of the same high quality of service whatever the nature of your contact with us, as we value each and every client. If we can help, we will help. 
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