High Speed Balance problem

[Spencer Scanlan]

Hi All,

I've had a look at various wheel balance and tracking threads but not found an answer to my question. If theres one out there please point me in the direction.

Basically I have the tracking out slightly to the left and a juddering motion from the steering wheel at over 75mph. I've taken it to various ATS, Kwik Fit type places who always say 'yeah, they're both out abit' and make some adjustments. The only difference is that afterwards the problems are in a slightly different place i.e. tracking of to the right and juddering at 80 instead of 70 say. I've tried taking it to a couple of local garages who have said they can't investigate because they can't drive it at 80mph (oh to live in Germany).
Is there anything else that could be a problem? What else can I do?

Thanks
Spence

P.S. - The car is a 1998 Vauxhall Astra 1.8 Sport.

 

[david and julie]

You need to ascertain wether it's the tracking out or a wheel/tyre problem.

I would suggest you try your spare first on the left then again on the right. test driving each time. If there is no difference at all it would suggest a tracking or suspension problem. If it still shakes, but at a different speed it is probably a wheel/tyre problem. Try this and let us know how you go on.

Although not as common rear wheels can also cause vibrations.

Also try and find a smaller independant alloy wheel/tyre supplier. The big boys are notoriously bad in this area if you get a dodgy fitter.

 

[AdamW]

I had the exact same problem once from a hire-car. It mounted a kerb on a roundabout (Worst handling car I have ever driven). No visible damage, drove fine, but above 70 it would judder.

Is it possible that you (or another driver) has mounted or clipped a kerb?

D&J do you think it possible that the bearings need adjusting/replacing?

If this is a Mk4, the bearings are expensive to replace as you have to change the whole hub assembly. £100-200 for parts, so not to be changed unless certain!

If it's a Mk3, I haven't a clue.

 

[AdamW]

Have you ever heard of wheel-balancing weights coming off wheels? That might cause similar problems too.

What if the garage has you drive the car at 80mph with the mechanic in the passenger seat?

 

[pipme]

Anything spinning may be whirling .... If rotatatives connected loosely, as in worn suspension, then imbalances will be magnified ....
Drive shaft joints etc

How's about an oldy, if it is still available, balancing wheels on the car ?
Can remember in days of yore that this could show up suspension faults as in the balancer continually varying without achieving a steady state.

With the tracking, they used to 'roll' the car back and forth to settle suspension, check, adjust tracking .... roll car back and forth, recheck .. If that method shows variance then there is wear present which is not allowing maintainable set-up.

P

 

[david and julie]

Adam...yes it could be wheel bearings or as pipme says it could be almost any suspension component. Spencer really needs to determine wether it's wheel/tyres or not.

A very slight imbalance or slight tyre fault will really magnify itself if something else is worn.

He should try as I said or swap the back wheels for the front and then try it again.

I would'nt trust any of the big boys on this job, as we have discussed before, they can be a bit rough if you get the wrong fitter. I think it more probable that he has a combination of balance/tracking problem that as not been properly sorted.

 

[securespark]

I had the exact same problem once from a hire-car. It mounted a kerb on a roundabout (Worst handling car I have ever driven).

Sure it wasn't the driver? Miaow!!

No offence!

 

[IanDB]

No offence!

Just "careless driving" officer!

 

[AdamW]

Well, that had been my first thought, actually! Went onto a large roundabout, near Heathrow, going about 30mph, a suitable speed for that roundabout. The fact that there was a beaten up old Golf (not GTI) on the inside track of the roundabout going faster than me showed that I wasn't going too quick.

The car steered at first, then just started to understeer no matter what I did. Lifted off the throttle, the tyres didn't bite. Tried the brakes, nothing. The car (a Focus, now you know where I got my opinion of it from!) hopped up the kerb and I managed to bring it to a hault with a road sign 2 feet in front of it, and a big ditch 1 foot to the left. My colleague in the passenger seat, who had witnessed it, said I was definitely turning the steering wheel. It was quite funny though, he screamed like a girl!

It was possible we hit some debris but when I got out and looked there was nothing on the road that would have caused that.

Anyway, it's only saving grace was that as well as handling like a brick it must have been built like one as it drove 50 miles back home after that!

 

[noflame]

You don't say how many miles on the clock.
Wheel bearings, however, are very unlikely to cause the symptoms you describe; if adjusting tracking makes no difference and just causes the problem to move about from side to side, the most likely cause of your problem is wear in one or both balljoints, or elsewhere in the front suspension /steering set-up-Balljoints is most likely, though. This is why adjustment makes no difference as the wear is still there no matter what you do.
If you don't know what to look for go to your local MOT testing station and book a test- this should show up any problems.

 

[david and julie]

Spencer. Having re-read your post several times I am confused by your description. The wheels normally track in or out,very slightly, not to the left or right, do you mean your car wanders left or right? or do you mean the steering wheel is left or right, off centre, after they have "fixed" it.

Incidently the wheel bearings can cause these problems, if very badly worn, but I agree this is unlikely here. You have probably had the usual Sh**e job done by a "specialist" chain.

Try and eliminate as we said and see how you go. Before looking at more expensive suspension parts.

 

[TexMex]

Just to chuck my tuppence worth in. It could be a worn out shock absorber.

Once you reach a speed where the wheel revolutions per second matches the resonance of the suspension, (or a multiple thereof), vibration will gradually amplify itself if there is not sufficient damping (even with the most perfectly balanced wheels).

If this is the case, you will find that driving even faster will stop the vibration. ie, you may find that at 90 it all goes quiet again.

Check the shocks. All it takes is a shove down on the wing each side. front and back as hard as you can. When you let the pressure off suddenly, the car should come straight up to it's natural resting point without any sign of a bounce. If it nods a couple of times, the shocker is stuffed.

As for the wandering. If the tracking is out, the car should tend towards a downhill path. ie due to the camber of the road, under normal circumstances it will wander to the left. But as you cross the centre line of the road (for instance while overtaking) you will find it wanders to the right.

Try it on an open stretch of clear road with a nice pronounced camber. On the left hand side of the road, pulls left, cross to the wrong side, pulls right. If that happens your tracking is out. If it don't then it can't be too bad.