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[Viral_Jim]

As per title, I'm getting a slight wheel wobble on the skip ('59 plate Zaf B 1.6 manual), but only under specific conditions.

The car is bang on, pulls up straight, no general issues. But, when travelling at about 60-70mph I get some steering wheel wobble, but only if I lift off the throttle. If I'm on the accelerator or brake, no wobble. I'm wondering if its a wheel bearing on the way out or a worn CVJ, but I'm not getting any rumbling which would be what I would expect from a wheel bearing. The clutch is also very worn (96k miles on it) and on my replacement list for the coming months, but I don't see any kind of connection.

If anyone has any ideas, I'd be most grateful. I'm not about to start throwing parts at it as tbh its mild enough to not be an issue for now, but I do know these things seldom get better over time.

[Doctor Gollum]

Tyres... Out of round or mis balanced.

Changing from mismatched ditch finders to Eagle F1s on the Alabama Mumsybus got rid of the vibrations I had on that. Changing the discs helped halve them to begin with and tyres took care of the rest. 

[Viral_Jim]

Given that it's currently shod in black and (apparently mostly) rounds on the front that's not a bad shout. I had new ones on the back as I found a nail in one inner wall, not done the fronts yet. Down to about 3-4mm so likely an MOT job in June anyway.

Slightly mystified as to why it's only on closed throttle though. I would have thought it would be speed dependent...

[LC0112G]

Can you feel it through the steering wheel?

If you can I'd be inclined to suspect something in the steering assembly - track rod end, center steering linkage, idler arm. Accelerating and braking both cause the steering geometry to squish in or splay out, and the loads in the various ball joints then pushes them onto their end stops. Whilst coasting the ball joints sit in a more neutral/central position where they can wobble about.

I don't see why the vibration would come and go if it were a rotating part like a brake disk or tyre - as you say it would just be speed dependent.

[Doctor Gollum]

Torque through the axle loads the rotating mass which stabilises the wheel. Lift of and the torque loads reverse along the shaft (relatively speaking) unloading the wheel allowing it to wobble.

Cue a much better phrased description and a healthy dose of derision but...

ROTATING MASSES

An Important consideration in the design and manufacture of any high speed rotating equipment is the balance of each component and assembly.

Unbalance in any high speed rotating components can cause noise, component wear, excessive vibration and reduction in bearing life.

Balancing, which is the process of attempting to improve the mass distribution of a body so that it rotates in its bearings without unbalanced forces, is critical to the performance to any high speed equipment.
For a body completely in balance it must have two things, ‘static’ and ‘dynamic’ balance. Static balance occurs when there are no rotational forces and the centre of gravity is on the axis of rotation. Dynamic balance occurs when there is no resultant turning moment along the axis

Wheels aren't necessarily statically balanced, ie they fall over left to their own devices which will affect lateral loadings imposed on the shaft/hubs etc... Higher speed will pull the wheel outboard and lower speeds inboard. I want to say gyroscopic precession, but not sure if that specifically applies

[Doctor Gollum]

Can you feel it through the steering wheel?

If you can I'd be inclined to suspect something in the steering assembly - track rod end, center steering linkage, idler arm. Accelerating and braking both cause the steering geometry to squish in or splay out, and the loads in the various ball joints then pushes them onto their end stops. Whilst coasting the ball joints sit in a more neutral/central position where they can wobble about.

I don't see why the vibration would come and go if it were a rotating part like a brake disk or tyre - as you say it would just be speed dependent.

Actual play will be heard as much as felt and will get worse. Also more prevelant across the speed range...

[Viral_Jim]

Thanks both.

I will get it jacked up, whip out the pry bar and see what wobbles  .

Failing that, as mentioned tyres need changing shortly regardless. 

[Marks DTM Calib]

Experienced this once on my ZafB, it was a failed shock absorber, so check them 

[TheBoy]

Intermittent wheel balance and brake judder type wobbles are often due to play in front suspension or steering, such as worn bushes.

So it does mean getting it in the air, and getting out a trusty pry and have a feel around.


If it always happens under the same conditions, such as always at 90mph, that tends to be balancing or out of round wheels.

[Andy H]

When a CVJ on SWMBO's Galaxy developed some play the symptoms started as a slight wheel/steering wobble that you could switch on/off with small changes in throttle opening.

The drive shafts are fairly heavy and I think what was happening was that a small amount of throttle would load the CVJ and centre the shaft. Ease off and the shaft was off centre. Lift off totally and engine braking loaded the joint again.

The play didn't seem excessive to me but the weekend we drove from Cornwall to Kent (and back) was enough to go from irritating to barely drivable.

A new CVJ fixed the problem.