Impact of Accessory Weight on the Performance of Your Jimny

Underestimating the impact that the weight of additional Jimny accessories has on the life of your Jimny and also the impact that this weight has on the performance and road handling of your Suzuki Jimny is often overlooked by many.

This blog covers technical points such as what are the preferred accessories selected by Jimny owners, a table of most typical accessories for your Suzuki Jimny 4×4 and the approximate weight of each accessory, as well as some basic test weight data measured by Des-Sol. We also discuss the impact that this weight has on the ground clearance of your Jimny when empty and loaded. We also cover the merits and importance of good spring design, the basic operation of shock absorbers and why it is vitally important to match spring and shock absorber when doing a 50mm suspension lift.

Introduction

What do the majority of Jiminy owners do after purchasing their new or used Jimny for the first time? The first thing most owners do is to go on a off road trip that the dealer sponsors or if they have mates that already own a Jimny they will tag along nervously testing out their 4×4 high and low range skills.

Once a few of these trips have been undertaken and these new owners really “get it” and start to understand and feel the magic of owning a Jimny, the “off road bug” really bites.

Accessorising

Without exception the next phase of owning and driving one of these iconic 4×4 vehicles is, how do I accessorize my little Zook? There are many options available, upgrading the sound system is one of the favourites as it is reasonably inexpensive and the standard sound system installed in the Jimny is not much to boast about.
However, ask any owner who has been bitten by the “off road bug” what he or she would do and the answer will undoubtedly be, looking into acquiring 4×4 accessories.

The Front Bumper

The most common accessory chosen as a first installation by Jimny owners is generally a new customised front bumper to provide a better approach angle when negotiating steep inclines, and most often the choice will be a bumper with a nice solid heavy looking Bull Bar attached. “The Approach angle is the maximum angle of a ramp onto which a vehicle can climb from a horizontal plane without interference. It is defined as the angle between the ground and the line drawn between the front tire and the lowest-hanging part of the vehicle at the front overhang.”

Basic Accessories

Along with a front bumper replacement, other options that are usually top of the list are typically, suspension lift or upgrade, customised rear bumpers, rock sliders, under body armour, steering damper, roof racks to carry additional loads, LED lights, 8000 pound recovery winches, high lift jacks and even a second spare tyre. Another low cost favourite is removing the back seats and adding a fridge and or additional packing space with a slider system for easy access.

Additional Weight

Couple all of the above basic accessories available together with additional loads when travelling for extended holiday periods such as passengers, bicycles, tents, food, clothing, paddle skis, additional petrol / water tanks, ammunition boxes etc. and you will find that you have placed quite an additional load onto your Jimny suspension system.

4×4 Accessories and Approximate Load Ratings

When preparing for serious 4×4 trips, bumpers, winches and other accessories are essential pieces of equipment to ensure you are ready to handle any challenge that comes your way.

When deciding on upgrading your suspension, it is important that you are aware that the accessories fitted to your vehicle come with a weight penalty that needs to be compensated by the spring (and sometimes shock absorber) rating to carry the additional load.

The weights specified in this table below are approximate and are to be used as an indicative guide only. Different makes and models of accessories will have different weights.

If you are unsure of the weight of your accessories it is recommended that you weigh them before fitting or weigh your vehicle before and after fitting to be sure.

It is important to note that when selecting the correct springs and shock absorbers, that you calculate the total weight based on accessories currently fitted to your vehicle not what you plan on fitting in the future.

The table below outlines the additional weight that each accessory adds to your vehicle.

The Devil In the Details

Not a lot has been said about being careful of the weight of the accessory that you add to your Jimny. However, a quick look at a typical accessories list above and their approximate individual weights should give an indication of what additional weight your Jimny may possibly be carrying.

Basic Weight Test

Des-Sol recently carried out some basic load tests to see how far a Jimny suspension drops due to additional loads. Looking at the data in the table below it can be seen that a load of approximately 195 kg (120kg plus a driver at 75kg = 195kg) drops your ground clearance by
-50mm with standard Suzuki Coil Springs and by -30mm with Des-Sol Dual Rate, Medium Load Coil Springs.

The 195 Kilograms could be made up of typically:

• Driver – 75kg
• Custom Front Bumper – 30 kg
• Nudge Bar (Bull Bar) – 10 kg
• Rock Sliders – 20kg
• Winch (Steel Cable) – 20 kg
• Roof Rack – 20 kg
• Jerry Can (Water of Fuel) – 20 kg

Spring Suspension

Looking at the above table it can be seen that by loading your Jimny with 120kg of accessories and one driver you will have dropped your suspension (reduced your ground clearance) by approximately 50mm when using standard Suzuki suspension coil springs or by 30mm when using Des-Sol Dual Rate, Medium Load Coil Springs. The important thing to remember here is that a reduction (compression) of the standard Suzuki suspension springs will undoubtedly have your vehicle bottoming out on the bump stops almost continuously over minor potholes in the road before you even get to a 4×4 trail. However by using our Des-Sol Dual Rate, Medium Load Coil Springs you will not bottom out as our springs are designed to “tension up” significantly as they are compressed. The Dual Rate design is created by varying the pitch of the spring throughout the spring length.

Shock Absorbers

The shock absorbers job is very simple to explain, it’s to keep the tyre in contact with the ground wherever and whenever possible. But in practise shock absorbers have to deal with a number of continually varying factors/conditions thrust upon it by the car and it’s suspension to contain rough terrain oscillations in a controlled manner over a wide variety of situations and conditions, so how does it do it?

The plunger consists of a dual direction valve operating in a tube full of oil. The oil gives resistance and the valve is calibrated to allow oil to flow past it in differing directions, regulating the amount of resistance in both “Bump” and “Rebound”. Combining these two actions gives the damping needed to control the spring’s oscillations. This basic design is known as the ‘mono-tube’ damper

When looking to upgrade your suspension it is vitally important to select both the shock absorber and the spring set as a combination of devices. This is to ensure that when the spring / suspension is fully extended, that the shock absorber piston does not “Top Out” and connect with the upper part of the Damping Oil Housing, damaging both the Oil Housing Seal and the Working Piston. The opposite effect is that if the Spring is fully compressed you do not want the Working Piston “Bottoming Out” at the base of the Damping Oil Housing damaging both the housing and / or the Working Piston. So in simple terms your suspension travel and your shock absorber travel should be matched to ensure that the shock absorber piston remains within the “Bump” and “Rebound” parameters at all times. This will ensure optimum lifespan of your shock absorber.

Selecting the Correct Springs

When considering upgrading your Suzuki Jimny suspension many owners do not consider the impact that incorrect spring design has on the life of your shock absorber. You can install the best and most expensive shock absorber on the market on your vehicle but if your springs are not correct chances are very good that the life of your shock absorber will be shortened significantly. A common mistake made by some Jimny owners who are lifting their Suzuki Jimny suspension by increasing the spring length is to simply take their existing Suzuki Jimny OEM springs to a spring manufacturer and have them to extend the spring length by another 50mm. This can lead to excessive shock absorber wear as over rocky surfaces the shock absorber piston is constantly travelling at its maximum “Bump” and “Rebound” levels reducing the life of the shock absorber. Although spring manufacture is simple enough it’s the design of the spring that is critically important. The following video compares the performance of two different aftermarket Jimny suspension systems. Viewers will notice how the first Jimny bounces excessively, indicating that the maximum “Bump” and “Rebound” levels on the shock absorbers are being constantly breached.