design - Land Rover section

 

Picking the best leaf spring

for YOUR Land Rover

Vehicle suspension springs are a compromise. The softer the springs are the more they move in response to bumps and the more they can articulate within the possible range of motion. The stiffer they are the more weight they can carry both on and off road and the less the body leans on corners.

The compromise is to find the spring rate that provides the most comfortable ride and best articulation for a vehicle's, intended axle weight range (from empty weight to full passengers and cargo). Rover went to a great deal of effort to come up with the best spring rates for each model of their home market vehicles (right hand drive versions). There are five different springs that Rover has used on the front of series II, IIA and III Land Rovers to tune the front suspension. With a little weighing and effort you can take advantage of the variety of available springs to fit a set of springs that are optimum for your vehicle.

The first thing to note is that Except for the 1- ton rear springs Land Rover springs come in handed pairs. This is a result of Rover fine tuning their springs for uneven side to side weight distribution of home market vehicles. Starting with the series I UK model there was more weight on the driver's side in the form of the driver, battery and fuel tank.

So to provide the softest ride and a vehicle that sits level they put stiffer springs under the driver's side rather than beefing up the pair of springs and making the ride harsher.

This was fine for the home and most colony markets where vehicles are RHD, but didn't work all that well for 109 station wagons nor for left hand drive Land Rovers. The 109 station wagon has the fuel spread out evenly across the rear so the handed weight was reduced to the driver and battery. Left hand drive Land Rovers have the weight of the driver on one side balancing the weight of the fuel tank and battery on the other side. The result is a similar weight on each front axle.

A left hand drive Land Rover with new handed springs will almost always sit listing to the right. Sometimes by as much as 6 inches if heavier duty springs are used on a Land Rover with a front fuel tank.

Rule #1 for left hand drive Land Rovers is never buy a handed pair of leaf springs unless you know the individual axle weights and one side is about 150 pounds or more greater than the other side.

Rule #2 The less weight  a spring is rated for the lower that spring will ride at empty weight (they all should be close to the same ride height a max on pavement load),  This means a 109 will sit higher with 1 ton springs than it will with regular springs.

Rule #3 The softer a spring is the greater the range of articulation until the articulation boundaries are met (ie frame stop, check strap or shock max. extension length)

Rule #4 Within reason, the closer a spring gets to it's max load weight the easier it can flex.  This means a softer ride

The next thing is how to decide what spring rate to choose:

Below is my interpolation of data provided by Land Rover. Minimums and maximums are conservative approximations.  These numbers should be taken as best guess approximations based upon weight ranges that Rover used each spring with and not as absolute limits.

Load your Land Rover to the maximum weight you plan to take off road plus full fuel tanks then weigh it at a public scale. Choose a spring for each axle from the table below that has a maximum rate closest to but greater than your vehicle's axle weights. This should get you the softest ride and best articulation with springs able to handle your off road driving needs for the way you load your vehicle. If you do not carry heavy weights in the rear, you may well be over sprung in the back and dealing with a harsher ride over those washboard roads than you need to.

As an example, The Green Rover weighs 2460 pounds on the front axle and 2980 pounds on the rear axle, fully loaded for trips with me and my dog in the vehicle. Side to side axle weights are less than 150 pounds different.

From the chart below, 276034 springs on the front and 279678 springs at the rear would provide the softest ride, best spring movement (articulation) and safely handle my Rover's weight off road.

If you want to achieve the smoothest ride and best articulation from those springs there are a few things that can be done.

 

88 & 109 FRONT SPRINGS

Spring number Minimum weight Maximum weight*

242863

1600

1700 pounds

241283

1700

1850

264563

1750

1950

265627

1950

2275

276034

2275

2550


* Maximum weight is maximum recommended cross country weight.

 

88 REAR SPRINGS

Spring number Minimum weight Maximum weight*

517589

1300

1950 pounds

517588

1950

2650

109 REAR SPRINGS

Spring number Minimum weight Maximum weight*

279679

1450

2500 pounds

279678

1500

3570

535173

1800

4200

Happy spring tuning!

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