Wayward handling when going straight.

[Stagn8]

Can anyone shed any light or have suggestions on the following issue please.

Audi A5 cab Quattro. When driving on a motorway fully loaded, four adults that is, the car just wanders about the road and needs constant steering input, sometimes a bit more than a nudge. It is particularly noticeable on the concrete sections of the M25 but also happens on other motorways (including in France). It is much less noticeable solo or two up.

Car is low mileage (22,000) and has new tyres (came with four new Bravuris 5HM 🤷🏻‍♂️🤷🏻‍♂️ when I bought it) just passed it’s MOT which suggests none of the myriad of bushings were looking nasty. 
 

It does seem to me that certain surfaces upset the car but should it be happening, or could be as simple as tracking?

Any thoughts appreciated. 

Edited August 19, 2022 by Stagn8

[Magnet]

Hello Keith,

Brav…. tyres?? Manufactured well east of the Thames estuary? Could be a contributory factor. What are the load rating of these tyres compared with the handbook specification? 
We take it you have set the tyre pressures at the recommended level of the load. Can you confirm. 
Kind regards,

Gareth. 

[Stagn8]

H’mmm good thought Gareth, not pumped them up from normal on this trip, though they are set to the mid level rather than comfort, didn’t really think of it as it hasn’t been important on any other vehicle I’ve had. However, I was towing a caravan with it in France earlier this year ( that means an extra 80kg loading at the extremity of the rear of the chassis) and had the same problem, and I know I had the tyres at the correct pressure for maximum loading, as recommended in the handbook and door plate.

In case it is important, it is on 19” wheels which seem to generate a lot of noise at the back over bumpy surfaces. It does seem that road surface plays a part but, what impact does tracking have, I have no idea what Audi recommend but I am under the impression it does have an impact on straight ahead stability, small amount of toe in to help with tracking in a straight line.

Load rating is 96y which is 730 kg I believe.

PS. Not too Far East, Czech and part of continental, so not all bad 😀.

Edited August 19, 2022 by Stagn8

[Magnet]

Thanks Keith,

You now need to do your homework via. your original handbook and or the wheel/tyre size specified on the sticky label - sometimes on the back of the fuel filler door. You will need to double check that the size of tyres fitted are to specification. It’s not out of the question  that ‘cheapest size that fits the rim’ are fitted at a point of sale. 
I would also question whether XL ( extra load) tyres maybe necessary under your load condition. 
Kind regards,

Gareth. 

 

[Stagn8]

Checked the tyres against the sticker on the door and they are as specified, they are also XL. So, all good there. On line reviews for the tyres aren’t exactly glowing but equally no one is flagging them as terrible.

[RoyC]

 

[Magnet]

So tyre pressures checked and set to the appropriate load? Treads wearing evenly across the width? 
At 22k miles we would not be expecting wear to be an issue, but always worth checking.

Kind regards,

Gareth. 

[jdragon]

What do you mean "set to mid level rather than comfort"?

You should inflate according to the recommended pressure for your loading condition as stated on the door plate.

And yes, if the tracking is out your car can pull to a side. Get it checked.

 

[Stagn8]

Tyres were new when I bought it at 18,000 miles so only 4,000 miles of wear and nothing noticeable on wear accross the tread.

If you look at the Tyre pressure sticker there are three settings, 'comfort' being the first and lowest setting. Tyre pressures are spot on for normal loading and use.

The inconsistent steering isn't a pull in one direction, it needs constant input from me to keep it online. Normally a motorway should be relaxing with minimum input on the steering but I am having to make small adjustments all the time. It only seems to be on certain road surfaces and fully loaded.it 

I'll get the tracking etc checked as it seems a good starting place. Do I need just the front or four wheel alignment? Not sure how much is adjustable at the rear.

Thanks all.

[RoyC]

26 minutes ago, Stagn8 said:

I'll get the tracking etc checked as it seems a good starting place. Do I need just the front or four wheel alignment? Not sure how much is adjustable at the rear.

Try changing the wheels from side to side, see if it makes any difference.

I had a set of new Dunlops once and one was faulty, used to make the car wiggle from side to side.

[Magnet]

Personally, if the tyres are seen to be wearing evenly, then I wouldn’t get the tracking checked, since the sales pressure will be on to adjust it even if it insignificantly out, and you and your wallet may be worse off. 

Kind regards,

Gareth. 

[Stagn8]

I agree Gareth, not keen on getting the tracking done as I not aware of anyone around my area who isn’t a multinational. Not saying they aren’t any good, more that their heart isn’t in it!
Changing tyres over is a good call, as I believe it is something marginally different somewhere as it only seem to happen when heavily loaded and certain surfaces.
Took four people ( including me😀)to Eastbourne on Friday, M25, A22 and the car was scary on the M25 concrete section. Came back via Brighton and A23 and it was the usual comfortable drive. Seems the road surface plays a big part in this, but the car should be able to handle it, never a problem on other cars I have driven on the same surface.
Looks like there is nothing definitive and probably just something on my car, so a bit of experimentation required 😕. 
Thanks for the help and if/when I find something I will update the thread.

[jdragon]

4 hours ago, Stagn8 said:

Tyres were new when I bought it at 18,000 miles so only 4,000 miles of wear and nothing noticeable on wear accross the tread.

If you look at the Tyre pressure sticker there are three settings, 'comfort' being the first and lowest setting. Tyre pressures are spot on for normal loading and use.

The inconsistent steering isn't a pull in one direction, it needs constant input from me to keep it online. Normally a motorway should be relaxing with minimum input on the steering but I am having to make small adjustments all the time. It only seems to be on certain road surfaces and fully loaded.it 

I'll get the tracking etc checked as it seems a good starting place. Do I need just the front or four wheel alignment? Not sure how much is adjustable at the rear.

Thanks all.

Does this occur at certain speeds as weighted imbalances will be more noticeable at a given frequency?

[Stagn8]

No, same between 50 and 70mph. Only noticed it on motorways so couldn’t say if it does it below 50mph. 

[jdragon]

1 hour ago, Stagn8 said:

No, same between 50 and 70mph. Only noticed it on motorways so couldn’t say if it does it below 50mph. 

MAGNET is right; if the tracking is out the tyres will wear unevenly, but at 4000 miles this could be difficult to identify.

Most places off a free tracking check.

Without driving the car, it could be either the tyre misshapen or needs balancing. Otherwise it's something more sinister. I personally wouldn't leave this too long, but rule out the basics first.

[Magnet]

Many thanks Jon,

Apologies for a differing point of view. Budget tyres at 4K miles will be at least 1/3 worn, so any wheel alignment will certainly be evident by this time. 
If there isn’t any evidence of irregular wear then I would be leaving well alone, as said.

OK, free check, but the temptation is to correct even minor discrepancies, and why would you if there isn’t any uneven wear. - as the poster has said?

In my book, if a tyre is misshapen then the result will be a shudder, but again the poster doesn’t complain of this. Same with wheel balancing.

I think you are right Jon in suggesting to get the car inspected ( for wear) despite the mileage. 
Kind regards,

Gareth. 
p.s. just noticed Keith’s reference to recent MOT - so another inspection? 
Ensure correct inflation for load and test again? 
Worth seeing if Keith can borrow another set of wheels and see what the difference is? 

[Stagn8]

Think you are getting a bit hooked up on this budget tyre thing Gareth. They are not the most expensive at around £100 a corner but after 4,000 miles they still have 8mm of tread, so somewhere under a mm of wear.

[jdragon]

Perhaps this could be a suspension issue like a little piece of spring has snapped off or a shock has suddenly failed? 

Either way, it needs inspecting because it's definitely not right.

[Stagn8]

It’s due an interim service so will get my local specialist to take a look and see what they come up with.

[Magnet]

Well done Keith. These budget ( ooops - sorry) tyres seem remarkable to have not worn 1mm in 4,000 miles of motoring, including load and towing use. That should easily give you a 30K plus life expectancy. Great. 
As I see it Keith:-

You either have tyres which aren’t up to the handling characteristics you would expect of them.

You are not inflating them to the correct degree for the load conditions. 

You have as yet, undetected wear in the suspension/ steering components. 
The car may have a possible hidden history of incorrectly repaired accident damage.

Or a combination of some or any of the above. 
As I see it, the next action is dependent on what you feel you want to do about its further investigation, since any without-car-examination will simply boil down to guess work. 

 

[Stevey Y]

On 8/21/2022 at 7:34 PM, Stagn8 said:

Think you are getting a bit hooked up on this budget tyre thing Gareth. They are not the most expensive at around £100 a corner but after 4,000 miles they still have 8mm of tread, so somewhere under a mm of wear.

Hi a little education for those who want to learn, Bavarius tyres are made in the Czech Republic and were originally back in the thirties a subsidiary of Michelin, in 1992 they signed a joint venture agreement with Continental AG [anyone ever hear of them], for the record one of the largest multinational corporations in Europe who produce just about every rubber O.E. part for German/European vehicles and as for Budget they could not be further from that or the Thames as the brand Barum only produce premium mid range to premium upper range tyres, tyres having watched this thread develop I can as a frequent user of the M25 concur with your problem as my car does the same depending on if you are driving on the concrete side of it or the tarmac side, this anomaly is due to the Audis steering set up as this is not to dissimilar to a version of centre hub steering this allows for very sharp and precise handling, the downside is if you drive on the undulating concrete crap thats known as the M25/M1 any largish discrepancy in the road surface drags at the steering, never had this problem with my Mondeos as they all ran Macpherson struts which the shock absorber runs on a ball race top mount so the strut moves with the steering rather than the steering moving around a static shock absorber, as for steering component wear, its highly unlikely as my A6 has now covered over 130,000 hard miles on a multitude of road surfaces and has no wear, when I could get them at a reasonable price I used Barum tyres for a good few years on my cabs and always got good miles and grip and I can vouch 100% for their winter tyres but alas they are now out of my price bracket so use Nexen another budget tyre company thats only been around for about ninety years which would lead you to believe they must be doing something right, just because you have never come across a brand before it won't mean its no good, just look beyond the name to see who owns the production licence.

Steve

[Magnet]

Thanks Steve,

So to try to boil this down, are you saying that this ‘difficult handling’ is a characteristic of the car - and even the VAG brand - and the tyres can almost certainly be eliminated from being a contributory factor, and indeed the suspension/ steering set up will be the culprit here under road conditions encountered on the M25? 
Kind regards,

Gareth. 

[jdragon]

I'll be on the M25 in a couple of weeks, and will report back.

[Stagn8]

Thanks Steve for your information. Also pleased you have noticed the same thing on the concrete sections of the M25 (have also noted it on motorways in France) I guess as a cab driver you were often heavily loaded as this is when it is noticeable, four adults in the car.

The weight in the back of two adults  and particularly when towing (about 80kg downforce at the very back of the car) will certainly alter the loading at the front wheels and I imagine could quite easily alter the way the steering reacts on certain surfaces, particularly if it designed to be pin sharp, leading to these tugs on the steering wheel.

I am going to get four wheel tracking done just for ‘an abundance of caution’ and the fact that the rear suspension is adjustable as wondering if the extra squat caused by the weight causes some unwanted movement in the rear suspension, impacting on the front end. Not sure when I will be repeating the fully loaded trip on the dreaded M25 to see if there is any improvement though.

[Stevey Y]

20 hours ago, Magnet said:

Thanks Steve,

So to try to boil this down, are you saying that this ‘difficult handling’ is a characteristic of the car - and even the VAG brand - and the tyres can almost certainly be eliminated from being a contributory factor, and indeed the suspension/ steering set up will be the culprit here under road conditions encountered on the M25? 
Kind regards,

Gareth. 

Thats the one, BUT its caused by the appalling state of our roads especially the M25 concrete sections which five years after its commission by Lady Thatcher started to break up AKA concrete cancer where the individual sections start to move away from each other which is why they are so keen to resurface the whole thing, if you take in to consideration that most heavy luxury cars run wishbone suspension with a 30 degree coilover shock absorber mounted to maintain dead centre pressure on the middle of oversize width tyre to stop this behaviour its no wonder that cars such as Audis fitted with any width tyre 235 + will drag due to the tyre foot print being so wide 225 is about as good as it gets with our roads, I think the generalisation that this applies to all VAG vehicles is a bit silly as most of the lower ranges use different width tyres which rarely exceed  a 215 width and won't ever encounter this problem as I explained before when I had a conversation with my neighbour an ex powertrain engineer at Wolfsburg he explained that people think bigger is better so thats what they sell them regardless of the fact that large wheels say 19 inch and low profile tyres are 40% heavier as the rims are reinforced due to the lower tyre profile therefore they are more prone to aquaplane and tramline on deviant surfaces so its not the set up thats wrong its the road surfaces, they are a large contributing factor, if you watch the old rally footage of when the quattros first started you will notice they ran skinny tyres say 195x60 x15 for example as this cut out 75% of steering drag over very rough terrain, if I drive with four passengers and a full boot up to Gatwick on the tarmac sections I only need to make minor adjustments to the steering if I go round to Heathrow from there its like playing chase the ace on the concrete plus you have the infernal clicking from the road except where they have ground about half a mile as an experiment the clicking ceases as does the wandering, I came down from 19inch wheels with 40 profile tyres to 17inch wheels with 55 profile tyres which gave a better ride and no compromise with the handling as well as about 6 miles more to the gallon I always used 101 XL tyres and never had a problem in 240,000 miles and with 200 HP and 420nm of torque it was no shrinking violet, final analysis is if you want this type of thing to calm down go down to 17 inch wheels and a slightly narrower tyre, if not you will have to live with it for the looks, my car does it on 225x55x17 so god knows how much extra noise/dragging you would get with a wider aspect tyre and 19 inch rims.

Steve.