does this sound like a wheel balance issue

[normspanners]

The balls or bearing cups spend most of their time running in the central position

No they dont, you have forgotten the fact that the drive shaft usually travels down to the hub from the gear box and also most cars have 1-1.5 deg caster. so the cv is constantly in an angle situation.

 

[normspanners]

The car 'wobbling' is usually the sign the tyres are starting to break up inside and the tread is not tracking the road correctly try swapping front to rear.
that is not to say it is not the drive shaft but the cv usually cause problems under load, not under clutch depressed situations.

 

[Masterofnone]

No they dont, you have forgotten the fact that the drive shaft usually travels down to the hub from the gear box and also most cars have 1-1.5 deg caster. so the cv is constantly in an angle situation.

Of course they dont run exactly true. That is why they are as they are.
However the shafts in the normal running position mostly run in the same plain so any movement is confined over a small area which becomes the position where most wear will take place. It is when the deviation is greater than this and you expose the rotating parts to both the worn and unworn areas that the problems occur.
Suspension travel is not so great that the shafts are wildly moving in and out all the time. Most steering inputs are also small at road speeds.
All of which is why you can sometimes get very localised wear in any cv joint.

 

[normspanners]

CV joints should not really get that much rotational wear if correctly aligned

They are never 'correctly' aligned. Due to suspension and camber angle, nevermind steering angle.

Suspension travel is not so great that the shafts are wildly moving in and out all the time.

The outer cv joint doesnt/ shouldnt, usually allow drive shaft movement in and out at all, that job is the inner cv either a tripod or pot joint called a rzeppa which allows for drive shaft plunge, it is the drive shaft down ward angle when running light or upward when loaded that constantly makes the cv run through an angle, as shown here, this is far more than one inch of turn on the steering.

 

[normspanners]

PS just remembered a couple of issues, the focus does have issues with steering rack thud when turning slightly from centre that can be steering column uj's or the spool control in the power rack, that could manifest itself as a wobble as the the PS fights itself maybe?.
Also check the drive shaft nuts for tightness they are known for coming loose, it usually could be the left hand one.

 

[Masterofnone]

They are never 'correctly' aligned. Due to suspension and camber angle, nevermind steering angle.



The outer cv joint doesnt/ shouldnt, usually allow drive shaft movement in and out at all, that job is the inner cv either a tripod or pot joint called a rzeppa which allows for drive shaft plunge, it is the drive shaft down ward angle when running light or upward when loaded that constantly makes the cv run through an angle, as shown here, this is far more than one inch of turn on the steering.

The point is at whatever angle it usually runs, that is where the wear will occur. It continually runs over the same areas most of the time so at some point you can end up with a clearly defined worn area within the tracks.
Usually I would argue in the straight ahead and normal loaded position when being driven as that is where it spends most of the time.
That the outer has limited in and out movement concentrates the wear even further into a defined area within the joint.
The one inch turn of the steering is the thing that takes everything past its normal wear limits because you have added an extra dimension to the movement and whatever type of bearings within the joint are then moving in and out between worn and unworn areas because it has strayed beyond the normal running relationship of the inner and outer parts of the same joint.
It is steering that ultimately moves the joint to its extremes not suspension movement but most of the time this is small at high speed so it further defines the wear.
That said if the wobble stops after an inch or so of movement it is not likely to be the outer although there could be a specific area of damage within the joint but it is is quite possible for an outer joint to cause wheel wobble.
I also seem to remember there was an issue with some Fords that required a change of valve or Filter within the power steering pump.

 

[normspanners]

We could argue this point for ever, what I am saying is that 1 inch of steering wheel turn, when calculated to actual road wheel steering angle, is not likely to be out of it's normal running zone---- read----- angle of the suspension droop + camber angle.

Steering ratio is the ratio of the number of degrees turned at the steering wheel vs. the number of degrees the front wheels are deflected. So for example, if the steering wheel is turned 20° and the front wheels only turn 1°, that gives a steering ratio of 20:1. For most modern cars, the steering ratio is between 12:1 and 20:1. as an average steering wheel is 14" that equates to 14 x 3.142= 44" divide 360deg by 44 = 8.2 deg steering wheel turn per inch then divided by avg. say 15:1 = less than 1/2 deg of road wheel steering angle, now when the average car has 1.5 degs camber angle alone, that is 3 times the inputted steering angle this is not taking the suspension droop angle of the shaft in to consideration, you can see that angle of the cv in its normal running zone is greater than the inputted steering angle by turning the steering wheel one inch. This means you would have to turn the steering wheel approx 4-6 inches to come out of the normal running angle of the CV. and in the case of the one pictured that would need 8-10 inches of movement.


message to the OP please check drive shaft nuts, the big one in the middle

 

[normspanners]

Steve,

Any luck with the wibble wobble?

 

[steveo3002]

right got 4x new tyres fitted today and its gone

wouldnt have really believed it but there you go , maybe the tyres sidewall was starting to go or something

thanks for the ideas anyway

 

[mike os]

Wow... surprise

 

[the snooper]

It was obvious it wasn't a drive shaft issue there was no drive shaft symptoms glad it was an easy fix for you

 

[normspanners]

maybe the tyres sidewall was starting to go or something

Post 42
nice and easy thats what we like !!

 

[steveo3002]

was really strange , yesterday we set off in the car and it was wobbling so bad i pulled over and checked all the wheel nuts as it felt like when a wheel is about to fall off

ive instructed the mrs to drive around pot holes not straight through them

 

[dobbslc]

Same with my missus! The front left alloy on her car is like a 50p coin on the inside.
45 profile tyres and Hertsmere councils *****y roads.

 

[normspanners]

Big problem 45's on alloys with speed bumps, I hate low profiles and think they look awful on 4x4's concrete jungle cruisers ---- HA wheels are bigger dia than most cars tyres and you cant drive on the road without bending them let alone off road, they are a joke.

 

[Wendelspanswick]

Post 42
nice and easy thats what we like !!

Er hmm, post #2!

 

[normspanners]

Post 2

Check you haven't got a bulge in the tyre, just on the edge of the tread.

But I thought he'd checked them after you saying that,-------- I was just reiterating or was it pontificating

 

[dobbslc]

Big problem 45's on alloys with speed bumps, I hate low profiles and think they look awful on 4x4's concrete jungle cruisers ---- HA wheels are bigger dia than most cars tyres and you cant drive on the road without bending them let alone off road, they are a joke.

Yeah I know what you mean about the poncey 20" rims on some 4x4s, the ride must be really harsh.

No probs with my truck though as I have 265/70/16's on it

 

[steveo3002]

wasnt any noticable defects in the tyre, good brands too

modern cars are too isolated , if i drive my old polo over a small defect you know all about it so learn to steer around them , the focus just steams over stuff and you dont feel a thing so dont even know youre killing it

 

[normspanners]

They are not too bad on air but ob steel its horrible