HZJ 78 Handling

[andrewm]

Hi all,

Was doing quite a lot of driving on 'landstrassen' today in and around Wuerzburg...

Do all HZJ78 have chronic understeer or is it just mine?

On the front I have middle OME, and Rear, I have the heavy OME (where we removed one leaf per side). I also have 285/75R16 BFG ATs

What I find really scary is not so much that the vehicle understeers, but that fact that as soon as it STARTs to turn (after tuning the steering wheel a very long way), it then starts oversteering, and you then have to correct very quickly...

I unfortunately have never driven a HZJ with standard suspension, so I don't know if this is normal.

I realise that its not a sports car, but slighly more humane handling would be great... Even the Landys steer better (Actually I know thats an unfair comparision due to their supperior suspension setup)

Is there anything I can do to improve this? or is it just a case of hang on tight in corners?

Cheers

Andrew

[netzmeister]

Hi Andrew!

Don´t panic - that´s quite normal...

Your 78 reacts really simple: He likes to drive straight on until you really force him to follow the curve. Then he puts up a good fight - and finally he kicks...

Just drive into the curve, adjust a little bit, lock the wheel and steer with the accelerator (unlike with little roadsters that doesn´t mean you control the breakout but the understeering).

But to be serious: Surely that depends on the springs and dampers. But you got a nice and approved combination - to improve that it would be a lot of effort.

Regards,
The Webmaster

[HermannJosef]

Hi andrew,

if you like to try a non-improved bushtaxi, just call me, we´ll find a solution.

Hermann-Josef

[andrewm]

@Alex

I was worried that you would say that... Is pretty much what I have been doing, just ocassionly though, you misjudge a corner, and then you start holding on for dear life as the body roll starts to take you into the oncoming traffic....  Oh well, 'Uebung macht der meister'...

Have also been using the accelerator trick (this also works very well with those small go-carts!  )

@HermannJosef
Thanks for the offer, but am normally based in Munich... Should you wish to try an 'improved' HZJ and are in Munich, feel free to drop me a line!

Cheers

Andrew

[moritz]

Dear Andrew,
to adjust your car's overall balance, you'd most probably have to play with the stabilizer bars, but this should be left to the chassis-experts.
You could try stiffer stabilizer-bar-bushings just in the front - which can be done quite cheaply - to correct the final oversteer, but this won't help your turning in, and total effect might be negligible (neglectable?).
On a 4x4 all this usually is unnecessary with enough rubber on it.
You might just use larger/wider tires/wheels and/or a better tread.
This improves the amount of available traction and steering response to a point, where your rig starts (re)acting like a male dog: Just lifting the inside rear leg, which then defines the limit virtually without under-/oversteer. Well, this might leave you longing for an advanced Torsen, or something similar, but that's another story.
Then there's another point I experienced with my 35x12.5 R15 versus 33x12.5 R15: At sizes this large, use a rim as large as possible. Preferably 17" (or 18" on BFG MudTerrain KM these days I think).
Those large sidewalls make for a tricky combination driven sharply on the street (and a sbJ40 becomes a bitch to catch even in the dry without power-steering, I can tell you...).

[moritz]

.....well,.........didn't realize that you're already on "285/75R16 BFG ATs" in my first reading, which makes me look quite foolish now, but for whatever it's worth, I'll leave it that way, now that it's typed.

In the end, maybe you're just too fast. We should discuss swapping engines, now.

[netzmeister]

Try using the brake - maybe that´ll help...

*ouch*

[moritz]

...just tried a silly little joke, netzmeister, not intended to be considered an educated guess or even super-professional advice. Don't worry...

[netzmeister]

I tried to take your little silly joke and make it more concrete - hoping that´ll make it even funnier...maybe that didn´t work...

[andrewm]

I have read somewhere that pulling the handbrake firmly in the middle of tight corners may also help....

It is supposed to settle the entire vehicle

Has anyone had any experience with this?



Andrew

[Gerhard]

Maybe this could help, but be warned: if you don´t have this rallye-car-driver-feeling in your hand, sudden oversteering tendency could be the result. I´m not quite sure, but I suppose what you mentioned above is, that your car needs this few moments until it starts reacting when you turn the steering wheel. In my opinion, this is caused by the front tyres, which need to deform.
Next, the load to the front wheels increases due to better friction, and the car reacts in a fine understeering tendency; caused by the lowered rear axle, which wants to GO OUT.

Don´t know, but if you pull the handbrake in this situation, this could become quite more funny that you really want, and heavy oversteering could be the result. Same, when you accelerate: in both cases, the car will oversteer, you´re taking away some friction resources from your rear tyres, and that will be quitted with Yippieayeyeaaahhhh oversteering!

Try it on an emtpy supermarket parking place, ideal conditions would be wet surface. And you will learn, that best help in this situation is to declutch, and not to brake - you give back your tyres all available friction for steering.

Regards

[andrewm]

@Gehard

The handbrake comment was a 'shot back' at those suggesting I use the brake, or replace my motor

You would probably have to pull the handbrake really hard on HZJ78, due to the fact that its a rear wheel drive, and to be honest, with that very looong body, would be to worried about taking another car with me...

As for it being cause by the tires, am not so sure... Landies with their coil spring setup dont have this problem.

Cheers

Andrew

[Gerhard]

Andrew,

hehe,
NOW I see the point......


like you, I have the same specific reaction in every courve I take with my Toyo - and this is a LJ73 with coil springs on front and rear axle. Seems to be independend from the type of suspension, but I can´t compare with Landy´s due to the fact that I do not know any guy who drives a Defender...


I really believe, this has something to do with the tyres; in winter, I use Nokian Hakkapeliitta 205SR16, which is designed as a street tyre for vans, and the handling is better than on the Pirelli Scorpio 235´s MT I use in summer. They are some kind of balloons....

[Piotr]

@Andrew, My HZJ (R.I.P) did have the same wheel size. However, mine never did show  significant understeer. On 'Autobahnauffahrten' I have even been able to provoke oversteering.
Well, I should add that I had apllied quite a high tire pressure 3.0 front 3.5 rear.  

Cheers
 

[andrewm]

@Piotr
Its not the understeer that bothers me, its the sudden oversteer shortly afterwards...

I let a friend of mine drive tonight, and you could see he had a great deal of difficulty dealing with the steering...

Is this a weight/ suspension problem? as my HZJ is normally unladen.... and no winch or bull bar on the front... (and I am running medium OME on the front and HEAVY (with one leafe removed) on the back.... - Could this cause this problem? Is there anyone around Munich who can give me a second opinion that this is ok...?

Thanks

Andrew