Suspension Upgrade Time

[ger08]

Just spent a week on a remote station and the road/track in was horrendous. So we’ve pretty much decided a mild suspension upgrade is needed. We currently have Pedders heavy duty coils and airbags in the rear as we tow a heavy camper and the front is stock. I would love any suggestions and things to beware off. I’m not looking at a two inch lift just better handling on rough corrugated roads.

[old Jack]

What are your ride heights (EBH) in mm?
Unloaded and loaded/hitched up, if possible.
Measure these from the centre of the wheel hub to the underside of the wheel arch in a vertical line.

Do you know what your front and rear axle weights are, both unloaded and loaded ?

What extra weight is fitted in accessoires and where is it located?

What extra weight do you carying and where when touring?

What is is the towball weight?

How much air do you run in the airbags?

What tyre pressures are you running?

What part number Peddars rear coils are fitted?

The Pajero Sport ans PB/PC Challenger have almost identical suspension so there is a large choice available, it also makes it easy to get it wrong!

Front Suspension, the factory spring rates on the front are too high, they are 17% higher than the Gen 4 Pajero factory spring rates and the problem gets worse as most aftermarket coils are 26% higher as a minimum, so this results in a hard ride especially when combined with factory and some aftermarket struts. Changing to lesser spring rate than factory and a longer coil so you get the ride height required, combined this with a strut that is softer on compression and firmer on rebound and you can improve the comfort and feel of the front suspension.

Rear Suspension, the factory spring rates are way too soft, so the rear does not carry weight well. This translates to the rear end wallowing through sweeping corners and rear end pitching especially when towing or heavily loaded, and the suspension easily bottoms out on compression. Factory shockers and the rubber cone assist springs are undersized also.

OJ.

[ger08]

What are your ride heights (EBH) in mm?
Unloaded and loaded/hitched up, if possible.
Measure these from the centre of the wheel hub to the underside of the wheel arch in a vertical line.

Do you know what your front and rear axle weights are, both unloaded and loaded ? No

What extra weight is fitted in accessoires and where is it located? Very little in accessories. Nudge bar and second battery system.

What extra weight do you carying and where when touring? I estimate the extra weight to be about 200kg

What is is the towball weight? Approximately 210kg

How much air do you run in the airbags? 20 psi when towining

What tyre pressures are you running? 40psi front and 45psi rears when towing

What part number Peddars rear coils are fitted?

The Pajero Sport ans PB/PC Challenger have almost identical suspension so there is a large choice available, it also makes it easy to get it wrong!

Front Suspension, the factory spring rates on the front are too high, they are 17% higher than the Gen 4 Pajero factory spring rates and the problem gets worse as most aftermarket coils are 26% higher as a minimum, so this results in a hard ride especially when combined with factory and some aftermarket struts. Changing to lesser spring rate than factory and a longer coil so you get the ride height required, combined this with a strut that is softer on compression and firmer on rebound and you can improve the comfort and feel of the front suspension.

Rear Suspension, the factory spring rates are way too soft, so the rear does not carry weight well. This translates to the rear end wallowing through sweeping corners and rear end pitching especially when towing or heavily loaded, and the suspension easily bottoms out on compression. Factory shockers and the rubber cone assist springs are undersized also. I became well aware of softness of the rear springs when we started towing.

OJ.

I have answered some of your questions above. You’re a technical guru.

[old Jack]

I have answered some of your questions above. You’re a technical guru.

Hi Ger08,

Without all the information I need I cannot give you a recommendation of what to consider.

Just looking at your replies so far I will point out the following.

1. 210kg of towball down load in significant especially without a WDH, is your camper a forward fold style?
At 210kg the rear axle load will be 302kg due to 92kg being transferred OFF the front axle. Combine this weight with the 200kg of extra touring weight and 2 front seat occupants 150kg total and you will be getting very close to GVM.
I would expect that the front ride height could increase by 10mm to 20mm with those tow ball loads. Therefore I would be reluctant to advise fitting raised front coils. The factory unladen front ride height is 520mm and the maximum ride height would be about 535mm-545mm so you retain 2/3's of the original droop travel. This is a legal requirement and is essential for the correct activation of the ASC/TC system.

Factory Rear ride height when unladen is 559mm and the minimum legal ride height is 519mm.
What is your ride height when all loaded and hitched up?
Peddars rear coils Part Number 7447 or 7254?

Assuming you have the standard 265/60R18 Passenger construction tyres, the 40psi and 45psi is very high, and this will be causing a hard ride and putting extra stress on the struts and shockers.
The Pajero Sport has a front axle load limit of 1360kg and a rear axle load limit of 1600kg, a pair of P265/60R18 109 tyres is rated to carry 1793kg at 26psi, 1894kg at 29psi, 1984kg at 32psi and 2064kg at 35psi, all these pressures are cold inflation pressures from the Toyo Load Inflation Tables. So you can see there is no need to exceed the tyre placard on the drivers B pillar, which will be about 29psi front and 36psi rear from memory.
What is the maximum cold inflation pressure embossed on the tyre sidewall?

OJ.