Steering shimmy - new tyres/wheels fitted

antiskeptic · 31-03-2012 04:09PM #1

I've picked up a set of s/h 18" in alloys for my B6 A4. I checked them individually for axial/radial run out and they were ok. Two of the (ditchfinder) tyres where 80% and 2 new tyres were required - me continuing along the ditchfinder route in having replacements fitted

The tyre garage who supplied/fitted the new tyres balanced all the wheels supplied off the car to them. They also checked tracking whilst the old wheels were still fitted (which have nearly new tyres): rear wheels fine, front wheels both pulling left. They adjusted the drivers side wheel but the passengers side wheel rod was seized so they left it. It was showing itself to be 2 degrees out.

I fitted the alloys the next day: new tyres to the front.

I'm noticing a mild shimmying from the steering wheel when I leave it go .. and a general shimmying from the car. This from lowish speeds up to about 60mph. I've not been beyond that speed. The shimmy wasn't there before the new alloys were fitted and I can't say I noticed it after the tracking adjustment and whilst I still had the old wheels on the car

I've noticed on the new tyres that:

- there are two dots, one red and one yellow. Neither is next to the valve (which I thought was the point of at least one of the dots). On one wheel, for instance, the red dot is at 10 o'clock (if the valve is at 12). And the yellow at 5 o'clock.

- there seems to be an exhorbitant amount of balancing weights attached to all the wheels - even the ones that didn't get new tyres fitted but were balanced during the job. Rather that a weight or two (which the wheels had originally) there are now whole strips of them. For instance, one wheel has a 6" strip of weights totalling 100g + a strip weighing 55g + another couple of weights totalling 15gr

Could there be an issue here or should I be looking elsewhere?

mickdw · 31-03-2012 04:46PM

Maybe your used wheels are crap or maybe the fitter is an idiot. As for leaving one track rod, well thats just a disaster of a job.

antiskeptic · 31-03-2012 05:19PM

mickdw wrote: »

Maybe your used wheels are crap

In what way (that would cause a shimmy without there being radial/axial run out)

or maybe the fitter is an idiot

Ditto above

As for leaving one track rod, well thats just a disaster of a job.

It was by agreement. I could have left it in to be fixed but need the car. Would you suggest he untrack the side he adjusted and give it back with both wheels pulling left?

dr.fuzzenstein · 31-03-2012 06:23PM

That many weights fitted to a wheel would suggest it's warped or buckled. If it wasn't, then there's something wrong seriously here.
If that was me, I'd jack up the car and spin the wheels by hand and look for uneven turning, wheels don't need that many weights if they're straight.

Nissan doctor · 31-03-2012 08:39PM

Did you not say, in your other thread, that they where replica wheels?

By all means bring them back to the garage and have the balance checked but replica wheels and the cheapest tyres available are not a great combination.

antiskeptic · 31-03-2012 08:51PM

dr.fuzzenstein wrote: »

That many weights fitted to a wheel would suggest it's warped or buckled. If it wasn't, then there's something wrong seriously here.
If that was me, I'd jack up the car and spin the wheels by hand and look for uneven turning, wheels don't need that many weights if they're straight.

LIke I say in the OP, I checked the wheels for radial/axial runout already and there's nothing all that untoward there.

It's not one wheel that has a pile of weights on - it's all of them - including the two that didn't have their tyres changed. Perhaps there's a clue in that: the wheels all had a couple of small weights on them when I got them - and two of the tyres aren't all that old. Which would lead you to suppose they were balanced not all that long ago and weren't found as wanting as they are now.

A dodgy balancing machine perhaps?

STOP PRESS:

I just went and checked pressures and found 3 wheels down a half a Bar from spec and the fourth down a bar. Pumped them up and took it for a quick spin and .. no discernible shimmy.

Checked the run out of the tyres themselves. Am seeing a 2mm or so radially 'dipping' away from true over a 6" or so section of the circumference in both the new tyres (not the wheel). I wonder is there a settling in time in this regard?

Nissan doctor · 31-03-2012 08:55PM

What means did you use to check the runout of the wheels?

antiskeptic · 31-03-2012 08:59PM

Nissan doctor wrote: »

Did you not say, in your other thread, that they where replica wheels?

By all means bring them back to the garage and have the balance checked but replica wheels and the cheapest tyres available are not a great combination.

As mentioned, when I bought them, the wheels had a normal compliment of weights fitted to balance those ditchfinders tyres.

Yet my guy, who balanced the 2 wheels which retained these part-worn tyres, saw fit to add a veritable string of weights to both of them. Either this guy or the last guy has got it wrong it would appear

What do you think about non-alignment of the tyre dot with the valve (in the case of the new tyres). The interweb in the main seems to indicate the dot>valve notion important.

antiskeptic · 31-03-2012 09:02PM

Nissan doctor wrote: »

What means did you use to check the runout of the wheels?

Dial gauge (I'm a mechanical eng with plenty of workshop experence). One wheel had a small blip on a bit of the rim but the body of the wheel is fine.

Nissan doctor · 31-03-2012 09:03PM

antiskeptic wrote: »

As mentioned, when I bought them, the wheels had a normal compliment of weights fitted to balance those ditchfinders tyres.

Yet my guy, who balanced the 2 wheels which retained these part-worn tyres, saw fit to add a veritable string of weights to both of them. Either this guy or the last guy has got it wrong it would appear

What do you think about non-alignment of the tyre dot with the valve (in the case of the new tyres). The interweb in the main seems to indicate the dot>valve notion important.

The dot lined up with the valve thing is something which is done by vehicle manufacturers during original assembly...its not relevant to replacement tyres/aftermarket/used alloys.

Wheel balancing can be off for more reasons then just the outer rim having a dent etc.

Like I said, I'd definatly get them rechecked, even if the shake is gone now with the correct pressure, as if the pressure has dropped that much in a couple of days there could be issues with the tyre beads sealing against the rims.

mickdw · 31-03-2012 09:11PM

antiskeptic wrote: »

In what way (that would cause a shimmy without there being radial/axial run out)

Ditto above

It was by agreement. I could have left it in to be fixed but need the car. Would you suggest he untrack the side he adjusted and give it back with both wheels pulling left?

It appears you have solved your issues but to answer some of your queries, if you have properly checked the wheels and they are straight, then if they are taking a pile of weights, that would lead me to believe they are very poor wheels.
If they are straight and good quality wheels, they wont take all those weights so your fitter must be making a mistake.
In relation to the tracking. If he set up properly locking steering straight on and then going about adjusting track rods and only adjusted one side, you would now have a car with off centre steering (when travelling straight) and even the wheel that was set right would not be presenting at the right direction to the road as the toe of both front wheels will average out when driving down the road and give the off centre steering. If you are not finding the steering off, the correction required might have been very slight, in which case you you wont see it.

antiskeptic · 31-03-2012 09:18PM

Nissan doctor wrote: »

The dot lined up with the valve thing is something which is done by vehicle manufacturers during original assembly...its not relevant to replacement tyres/aftermarket/used alloys.

Okay

Wheel balancing can be off for more reasons then just the outer rim having a dent etc.

Like I said, I'd definatly get them rechecked, even if the shake is gone now with the correct pressure, as if the pressure has dropped that much in a couple of days there could be issues with the tyre beads sealing against the rims.

I'm guessing he under inflated. He put two new tyres on and switched one of the part-worns to a different wheel (to keep the kerbed one to the front with a new tyre). They were all down half a bar. The wheel which had nothing done to it was the one that was down a bar.

But I will get them re-checked for balance somewhere else.

What do you think of the 2mm dipping in the tyre itself (that is to say, the outer circumference dips towards the centre of the wheel). Is it a question of letting them bed in?

Nissan doctor · 31-03-2012 09:20PM

antiskeptic wrote: »

Okay

I'm guessing he under inflated. He put two new tyres on and switched one of the part-worns to a different wheel (to keep the kerbed one to the front with a new tyre). They were all down half a bar. The wheel which had nothing done to it was the one that was down a bar.

But I will get them re-checked for balance somewhere else.

What do you think of the 2mm dipping in the tyre itself (that is to say, the outer circumference dips towards the centre of the wheel). Is it a question of letting them bed in?

The tyre imperfection is more likely just slack manufacturing tolerances. You see it regularly in certain tyres.

antiskeptic · 31-03-2012 09:21PM

mickdw wrote: »

It appears you have solved your issues but to answer some of your queries, if you have properly checked the wheels and they are straight, then if they are taking a pile of weights, that would lead me to believe they are very poor wheels.
If they are straight and good quality wheels, they wont take all those weights so your fitter must be making a mistake

Further checking required on this..

In relation to the tracking. If he set up properly locking steering straight on and then going about adjusting track rods and only adjusted one side, you would now have a car with off centre steering (when travelling straight) and even the wheel that was set right would not be presenting at the right direction to the road as the toe of both front wheels will average out when driving down the road and give the off centre steering. If you are not finding the steering off, the correction required might have been very slight, in which case you you wont see it.

The steering is as it was before - pulling to the left a bit, although perhaps not as much. I've to free up the seized tracking rod before progressing further here. Cheers..

antiskeptic · 31-03-2012 09:23PM

Nissan doctor wrote: »

The tyre imperfection is more likely just slack manufacturing tolerances. You see it regularly in certain tyres.

Pirellis and Dunlops and Bridgestones you mean?

(I've seen the same on my motorbikes Michelins and can't say I noticed anything here but maybe cars are different)

Steering shimmy - new tyres/wheels fitted

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