You can modify you shiny, too!

Traditionally we have always covered used vehicles when we have written about suspension modifications – what to do to your Patrol or Landcruiser, or maybe even a Disco or old Rangie.

But what about the new “shinies”?

It’s a fact of life that many of the latest “softroaders” or recreational 4WDs as we like to call them, have a lot of ability when it comes to going off-road – except that they don’t have low ratio transfer ‘boxes – with electronic gizmos that go a long way towards improving their  capabilities.

However with most of them there’s one thing missing, and that’s ground clearance.

Today’s recreational 4WDs are getting lower and lower as designers try to improve ride and handling on-road, but this is the very thing that’s limiting their use off the beaten track.

However, in our December 2008 issue we tested a Hyundai Santa Fe which had been extensively modified to make it more off-road capable, and this resulted in us being able to take it up the famed (and tough) Maratoto Trail in the Coromandel, a track usually reserved for 4WDs with full-on low ratio.

The modifications to the Santa Fe included raising the suspension by 50 mm at the front and 60 mm at the rear, and changing the shock absorbers for longer and more robust ones to take advantage of the increased rebound travel.

The lift was made possible by fitting new, longer, springs, although the normal spring rates were retained to ensure compliance was not affected.

And of course doing this meant there was plenty of room to fit mud tyres, and just to round things off a sturdy underbody guard was added.

The test Santa Fe was also fitted with a manual gearbox which in many respects limited its ability to travel slowly over the bumpier parts of the track (thank goodness for that big alloy guard) but an auto ‘box, which is standard on the Santa Fe, would go a long way to solving this problem, though if you’re going to require lots of torque converter slippage it would require a gearbox oil cooler.

However, there was one thing that changed dramatically, and that was the vehicle’s on-road performance.

Raising the suspension also raised the centre of gravity, making for more body roll in cornering, and this, coupled with those Goodyear Wrangler MT-Rs, meant one had to be much more circumspect when it came to travelling at speed on tarmac.

In fact that’s one of the first lessons you learn when you do a suspension lift – for every action there’s an equal and opposite reaction.

Increase the ground cleranace, which improves off-road ability, and you reduce on-road ability to the same degree – or sometimes even more.

So before you even start planning to do a lift you must decide if you’re going to be able to live with it, especially if it’s on your only vehicle.

There are many aftermarket kits which will improve your vehicle’s off-road ability to the level you want,  and most of them are model specific, with years and years of experience behind them – always bearing in mind that Land Transport Agency has specific rules you must follow to ensure the conversion is safe.

Internet users can check on-line here http://www.landtransport.govt.nz/vehicles/modification/index.html.

The lowest level of conversion is to change the shock absorbers so the suspension becomes firmer, making it more resistant to body roll and ensuring that your wheels retain contact with the ground – and thus grip – in off-road conditions.

After that the modifications range from minor lifts to really useful lifts that incorporate not just suspension changes but wheel and tyre swaps too.

Depending on the level of modifications Land Transport’s Low Volume Vehicle certification may be necessary to ensure the vehicle remains roadworthy.

Here are a few things to look out for when doing a suspension lift.  But if in any doubt at all check with a reputable supplier or experienced installer BEFORE you start.

• Lift blocks. These are the cheapest and easiest way to lift your suspension, but they can create problems, notably axle tramp which reduces grip and traction. They should NEVER be used on a front axle. Lift blocks also alter driveline angles, which puts stress on the universal joints, and can shift the position of the axle itself so tyres no longer fit in the mudguards.

• Extended shackles. These have many of the disadvantages of lift blocks, especially when used at the front. It also takes shackles which are twice as long as the lift to achieve a gain (i.e. a 4 cm lift will require an 8 cm longer shackle), resulting in a lot more sloppiness in the suspension. Shackles should generally not be any longer than they have to be for the suspension to work.

• Driveshaft length. Even with 30 cm long slip yokes it’s still possible for driveshafts to pull apart in extreme conditions, especially if you’ve used reverse-shackle conversions or lift blocks. Measure the driveline length with the suspension at its extremes to ensure your driveshafts are going to be the right length.

• Brake hoses. If you lift the suspension it’s going to put the wheels (and the brakes) further from the bodywork. And as a result brake hoses are going to be too short – maybe a LOT too short if you’ve done a good job with your lift. And when you replace, use braided stainless steel hoses which can take the extra knocks you’ll find now your vehicle is more off-road capable.

• Make sure all your brake lines are well fastened. A solid brake line will vibrate if there’s too much length between clips, and this will eventually lead to fracture.

• Shock absorbers. Again, as the suspension is lifted so too should a longer  shock absorber  be fitted. But not just by the same amount – better articulation could mean you’ll need even longer ones, and you may also have to change the mounting points to allow for new working angles.

• Bump stops. Don’t throw these away – they are necessary to prevent damage to your suspension parts when the suspension bottoms out, cushioning the load on springs and shock absorbers and preventing axle housings from bending.

• Steering stabilisers. If your vehicle is properly set up you won’t need anything to stop the steering shaking about. Usually steering stabilisers are used to compensate for worn steering parts, poor alignment or badly balanced tyres. They increase the drag on the steering, making it slow to react.

• Drag links. Some suspension conversions can cause problems with clearance of the steering drag links, or even bind in the tie rod ends. One “solution” is to put one or two bends in the drag link to “adjust” this – but it’s not really a solution at all since bending equals weakening, and this can lead to eventual breakage.

One final thing to remember. If you’re doing a major lift, you affect not just the suspension but could end up having to extend a lot of hoses, wires, cables, and shafts.

You can find out by trial and error, but a good kit will come with a set of instructions and all the parts you need. Generally the more you pay, the easier it is. But follow the directions – they are there for a reason. And if in doubt, contact one of our experts.