Death Wobble (again)

[rowan90]

Right so I have a 90 on a Galv chassis with the following modifications: 35" Maxxis Creepys, 15x10 modulars, terrafirma light duty +2" lift springs and 5" 4 stage shocks, sitting on 3 inch blocks all round, with adrenalin 4x4 cranked front and rear radius arms, adjustable panhard rod and freshly re- UJ'ed wide angle propshafts. I have tried everything and there is no play anywhere in swivels both top and bottom, preloaded positively, any of the ball joints, the drop link arm or joint and the whole truck has been polybushed, BUT! going above 35 mph is deadly, the wobbling is uncalmable through the steering wheel and the wheels both look like they are wobbling left to right. Truck has had a dead ahead wheel alighnment but is no better after it than it was before.

Someone please help? Swapped the chassis in February but only started a couple months ago

 

[Boris113]

I would in the first instance double-check your panhard rod bushes/bolts for play, that often produces a rather unnerving death wobble. Have you had your wheels balanced recently?

[Blanco]

Two quick suggestions, steering damper and borrow some sensible tyres.  Steering dampers sometimes get forgotton but can give serious wobble.

Borrow some road wheels and see if it goes away?

[rowan90]

Cheers folks, I will double check panhard rod, there is a steering damper on the way and shall try somne roadwheels!

[bishbosh]

My money is on the tyres too. Best fix for large angry rubber  is to put about 200g of ceramic airsoft beads into the tyre and remove all lead balancing weights from the wheel rim. Trust me it works!

[Snagger]

What angle of castor do you have?  That much lift will change the castor a lot.  It’d cause the prop to be out of balance too, as the rear UJ will be more deflected while the front UJ is straightened.  A double cardan prop might work better, but that would just cause vibration, not handling problems.

Have you checked the wheel bearings?

[rowan90]

8 minutes ago, Snagger said:

What angle of castor do you have?  That much lift will change the castor a lot.  It’d cause the prop to be out of balance too, as the rear UJ will be more deflected while the front UJ is straightened.  A double cardan prop might work better, but that would just cause vibration, not handling problems.

Have you checked the wheel bearings?

Not sure about the castor, but ive seen castor corrected balls available...? To be honest it sort of started all of a sudden after I let my pressures down.

[FridgeFreezer]

Tyres that big will find all the weak spots and worn joints in your system. It's a lot of weight waving around on the end of a lever. Could be any & all of the things people have mentioned. If you've put a lift on and not corrected the geometry that will never help.

[Bowie69]

A 5" lift and 35" tyres on 10" wide rims is going to be most of your problem.

Anything loose on the front end can cause this, check it all, replace if at all suspect.

[bushwhacker]

I'll go panhard rod as I have had similar experience.

Do update please.

Regards Mark.

 

[Jon W]

Check the bolt holes haven’t gone oval with wear as this can introduce play to the system.

 

[Snagger]

Check the tracking adjustment, too - I have only ever used standard rims and tyres on my RRC, but bad track rod adjustment made is leap all over the road at speed and hop uncontrollably from rut to rut on the HGV worn lanes of motorways.  Not the same as death wobble, but could have a similar cause, and the wobble may have been avoided in that case purely because I had the standard dimension and weight boots.

[rowan90]

Appreciate the input! Shall do a new steering damper and panard rod adjustment and keep you updated!