4x4 suspension 101

4WD Accesories

Dollar for dollar a suspension upgrade can be one of the most cost-effective ways to improve your 4x4. But where do you start? NZ4WD magazine Editor Ross MacKay offers his thoughts on the subject.

Flick through the pages of any issue of NZ4WD and you will find plenty of ads from reputable companies selling suspension upgrade parts and services.

Once you start looking the choice is vast – from simple replacement of your OEM struts, coils, leafs and dampers with aftermarket equivalents, to extravagant lift kits which will see your humble daily driver or weekend warrior tower over you like a Transformer.

Check through our feature this month and you can read about how much work has to go into developing aftermarket packages which meet all the relevant government standards around the world. 

Here, what you can and can’t do is set out by the Land Transport Safety Authority (LTSA) with much of the behind-the-scenes work done on its behalf by the Low Volume Vehicle Technical Association (LVVTA).

Simply put, if your 4x4 (or any other road-going vehicle) is factory standard and unmodified all it needs to be used legally on the road is a rego and WoF.

Any mod can make a difference

If it is modified in any way, however, it ‘may’ need a low volume vehicle (LVV) certificate to get a WoF.

Your average bar room expert will be able to tell you all about what can and can’t be done below the LVV threshold. But like anything it is better to go to the source (in this case the NZTA website at www.nzta.govt.nz/vehicles/warrants-and-certificates/modifying-your-vehicle/) and find out for yourself. 

It’s also a good idea to jump on the web and do some research, particularly if you want to modify a 4x4 not sold here in great numbers.

Consider the legalities

Here we are lucky that we have any number of reputable distributors/retailers who have made it their business to know the Low Volume Vehicle (LVV) rules backwards. So for heaven’s sake talk to as many as you need to, to  make sure what you want to do (particularly around suspension lifts and things like wheel spacers) is within the law.

No use bleating and moaning when you are knocked back for a WoF by something as simple, for instance, as wheels and tyres poking out of the guards for want of some wheel arch extensions or simple strips of rubber.

A weighty matter

Before you kit out your new DC turbo-diesel ‘work ute’ it’s worth considering what the mods you plan are going to do to the Centre of Gravity (CoG) and/or the tare weight.

Adding a heavy steel bull bar (which could weigh up to 90kg) and winch up front can really screw up your fore-aft weight distribution. As can adding heavy tool chests directly above and/or behind the rear axle line.

If the same ute is then expected to carry four burly blokes (weighing, with safety gear over 100kgs apiece) you can quite easily use up all your 900+kg tare weight allowance, rendering your ute a handful, not to mention technically illegal to be driven, on the road.

Do it once, do it right

Finally, in the same vein, make sure you finish speccing up your 4WD the way want it (including the heavy bits like front bar, winch, and rear tray or luggage compartment/drawer system/fridge, etc, etc BEFORE you upgrade the springs and shocks.

If you don’t, the springs that suited the unmodded weight of your truck will be marginal/too soft for the modified, and with it considerably heavier, version.

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