4WD MODIFICATIONS - SUSPENSION & BRAKES
We fitted a test set of Bilsteins to the Outback Travel Australia LandCruiser 75 Series and they did 10 major bush trips at a full 3.5-tonnes GVM on some of the worst roads and tracks in the Outback.
Bilsteins have been one of our preferred shock absorber brands since we did a test of many different after-market dampers some years ago. The Bilstein mono-tubes performed better than any of the twin-tube shocks we tested.
When the test started our 75 Series was fitted with after-market Kings Springs’ leaves that had a 50mm lift over standard.
In addition we had a pair of Polyair airbags on the rear and these were inflated to 30psi maximum when we slid our half-tonne Tray Tek camper on the back. These low-pressure airbags helped preserve unladen ride height and wheel travel, without unduly stressing the chassis.
An all-leaf suspension doesn’t have car-like ride quality – far from it – but the Bilsteins softened the standard ride quality by virtue of much better ‘bump’ damping and more powerful ‘rebound’ damping than the standard shocks.
There’s a popular myth fostered by some misguided suspension ‘specialists’ that you don’t need much bump damping – just plenty of rebound damping – and ride quality will be good. This isn’t true. It’s important that a shock absorber controls both bump and rebound actions and we haven’t found many mainstream dampers that do as good a job of that than Bilsteins.
Sure, you can buy full-race shock absorbers that do a better job, but be prepared to pay out at least a grand each for them. The Bilsteins we tested were around $220-$250 each.
Our LandCruiser, ‘Harry’, hit the 85,000km mark on the Bilsteins after our winter 2016 trip, so although the ride quality was as good as when they were originally fitted, we thought it was time to have them checked by the local distributors, Sydney Shock Absorbers.
The shocks came off and were checked individually on the company’s shock absorber dynamometer.
We expected to see some evidence of performance fall-off through wear, but there was hardly any difference between the dyno traces for bump and rebound action when compared with brand new front and rear Bilsteins.
The only maintenance they needed was a set of new bushes!
The up-front cost of a set of Bilsteins may be more than for some other brands, but the payoff for us was obvious.
There’s one caution with Bilsteins, as there is with any mono-tube shocker: stone damage hazard. A conventional twin-tube (inner and outer tube) shocker can take a stone strike that deforms the outer tube, without affecting shocker operation.
However, a mono-tube needs some shrouding from flying stones, because any denting will hamper piston action.