Grenadier unstable steering offroad.

[Kalthunayan]

Hey guys, during my last overlanding trip my grenadier was very unstable offroad, the car seems to shift left and right in the dunes which makes the car difficult to control.

Changes made to the car: 285 70 17 tires, Eibach lift kit 1.7” Front 1.2” Back. About 240kg worth of weight (excluding passengers.)
Anyone has any idea of why this issue has occurred? The only change to my previous trip was a 120liter water tank.

 

[TheDocAUS]

Do you have front and rear diff lockers? Did you engage either one? Was the car placed into offroad mode?

Where is the 120 litre water tank located? It may affect centre of gravity.

Did you have ESC OFF engaged?

Table complied by @Michael H.

 

[mcdoogs]

Was that big water tank on the roof?

 

[Kalthunayan]

Do you have front and rear diff lockers? Did you engage either one? Was the car placed into offroad mode?

Where is the 120 litre water tank located? It may affect centre of gravity.

Did you have ESC OFF engaged?

Table complied by @Michael H.

View attachment 7888484

Yes off-road mode was activated, I have no front & rear lockers so my car was on 4H. The water tank was in the trunk. slightly on the left side not really in the middle. its a rectangular plastic water tank with no baffles or breakers (breakers are quite common here in Kuwait). it could be due to the tank I don't know but the way the car moved around the dunes i was slightly surprised. I did visit my dealer a couple of days before my trip i had a banging noise in my steering dampener so they removed it and installed it again with some extra tightening. could it be due to the extra weight on the car? suspension is heating up quickly?

 

[Tinerfeño]

If the water tank is large, flat and not full it will have a significant effect regerdless the location. Ships have capsized because of this free surface effect.

Free surface effect - Wikipedia

en.wikipedia.org

 

[mcdoogs]

Did you have the center diff locked? Remember the grenadier has an extremely rudimentary offroad traction control, nothing at all like LR or Toyota's systems so it's probably not going to help much with torque vectoring on soft sand. Just thinking about it, constantly digging in on one side more than the other could make it feel a bit 'slidy' left <-> right. I'm no expert, especially not on the kind of sand you ya'll have there, but Robert Pepper recommends having the center diff locked in sand: https://l2sfbc.com/should-you-lock-your-centre-diff-for-offroading/

If you were center locked, and you werent overloaded (although 240kg plus 2-3 people would put your wieght well over 6000lbs and thats gonna be felt in loose conditions, including 100kg water potentially sloshing back and forth) then you might want to get your steering looked at.

 

[Kalthunayan]

Did you have the center diff locked? Remember the grenadier has an extremely rudimentary offroad traction control, nothing at all like LR or Toyota's systems so it's probably not going to help much with torque vectoring on soft sand. Just thinking about it, constantly digging in on one side more than the other could make it feel a bit 'slidy' left <-> right. I'm no expert, especially not on the kind of sand you ya'll have there, but Robert Pepper recommends having the center diff locked in sand: https://l2sfbc.com/should-you-lock-your-centre-diff-for-offroading/

If you were center locked, and you werent overloaded (although 240kg plus 2-3 people would put your wieght well over 6000lbs and thats gonna be felt in loose conditions, including 100kg water potentially sloshing back and forth) then you might want to get your steering looked at.

My center diff was not locked, I've done a trip before and the car was perfect. every since I got the water tank, it started doing crazy uncontrollable shifts left & right. although the trail was quite a rough one. i think i need a couple of tries to see where exactly is the issue. A friend of mine was following me and he was pointing our he had a similar issue with his Nissan Patrol, but i doubt it was as bad as me. this could be due to the trail and I'm just overreacting. could be due to the trail and the water tank.

 

[Krabby]

Hey guys, during my last overlanding trip my grenadier was very unstable offroad, the car seems to shift left and right in the dunes which makes the car difficult to control.

Changes made to the car: 285 70 17 tires, Eibach lift kit 1.7” Front 1.2” Back. About 240kg worth of weight (excluding passengers.)
Anyone has any idea of why this issue has occurred? The only change to my previous trip was a 120liter water tank.

If the issue started only after adding the water tank, I'd start there (remove/empty tank) and hit same trails/dunes. If the tank was full, 120L weighs over 450 kilos/1,000 lbs. - if that was sloshing around it would certainly affect stability (even more so if it wasn't centered in the truck).

edit - trail is far away, see if you can find something similar closer to home
second edit - 120 litres is 120 KG/~265 pounds. If, however, you were carrying 120 GALLONS of water, my numbers were correct.

 

[landmannnn]

It sounds like you should have been in low ratio with the centre diff locked, hopefully not with tyre pressures at road levels - more like 22psi.
Agree with the above, 120kg of water moving around would have some effect.

 

[Kalthunayan]

The trail is 1500km away . Anyways thank you guys for the feedback. Will do some testing and let you guys know. (If anyone is interested.)

 

[Tinerfeño]

If the tank was full, 120L weighs over 450 kilos/1,000 lbs.

120 litres of fresh water weights exactly 120 kg.

 

[Krabby]

120 litres of fresh water weights exactly 120 kg.

You sir are correct and I'm an idiot. That's the weight of 120 GALLONS! Damn metric system

What's funny is that in my head I knew that seemed really heavy but it kept coming out to that weigh! Thanks for the catch.

edit - that's 120 AMERICAN Gallons at ~8.34 pounds per gallon, as opposed to 10 pounds per British/Imperial gallon. Oi.