So you drive a late model 4WD ute or are thinking of getting one? The chances are that it will have independent front suspension (IFS). Love em or hate em, IFS is now dominating the 4WD market (and in particular the ute segment) today. Check out this guide to get the best out of the IFS setup on your ute.
SO WHAT’S ALL THE FUSS ABOUT IFS?
There are two main reasons that IFS has proliferated in recent years. It is cheaper to manufacture and the suspension gives car like performance. Hard core offroad enthusiasts look at the IFS with disdain citing limited wheel travel and weak CV’s as reasons why you can’t venture anywhere off the beaten track in an IFS. Whilst they may be right when talking about the offroad competition scene, for the vast majority of us, the IFS provides a good balance between daily driving duties and offroad performance.
IFS design has come a long way in recent years and while some manufacturers have stuck with the torsion bar suspension setup, others like the HiLux, Triton and Navara have dropped the torsion bar design in favour of coilover independent strut configurations. This finally offers the offroad the enthusiast he opportunity to tweak the suspension to tilt the scales more towards offroad performance than the factory configuration which is more suited to mundane daily driving duties, so many of us do far too much of!
The early IFS utes were mainly equipped with torsion bar suspension where the front springs are basically straight pieces of spring steel that rotate under torsional load.
This design is still alive and well today in vehicles like the Ford Ranger/BT50. Generally the torsion bar is connected to the lower control arm so it adds a few more places to get hung up on. Toyota, managed to engineer a torsion bar suspension setup for the pre-2005 HiLux that attached to the upper control arm that reduced the chances of getting hung up.
The ride height of torsion bar sprung vehicles may be adjusted by turning adjuster bolts. Too much can bend the adjusting bolt or put the shock absorber outside its normal travel range. This may also cause the suspension to hit the bump stop prematurely, causing a harsh ride. Aftermarket torsion bars may use reclocked adjusters to prevent over-rotation.
For the torsion bar setup, there is not much you can do to improve lift and flex. 25-30mm of lift is a practical limit as beyond this you will start wearing out suspension bushes and CV boots quite quickly. After market torsion bars are available but it is probably not worth the expense unless you have loaded up the front axle weights by fitting a winch. Some people also shorten the bump stops to regain some travel but this would be considered in most states as being an illegal modification. If you do want to fit larger tyres, probably the best option is a mild tweak of the torsion bars, adding a body lift and doing some trimming to fit larger tyres. Whilst there are some kits out there that provide big lifts by dropping the diffs with extra cross members, Ken O’Keefe at the Ultimate Suspension reckons that they try very hard not to fit this style of suspension kit to any torsion bar suspension ute that is going to be used offroad and not just posing on city streets.
The limitations imposed by torsion bars means many hard core enthusiasts reckon the only thing to do with the IFS front end is to cut it all off and weld on a solid front axle!