Inside Tyre Wear
 

omething i have noticed on my S8 both inside shoulders & was curious to see what the largest audience on the forum have experienced with the B5s ?

Obv camber can't be changed each side independently on the front and sub-frame was centered last year etc. Perhaps its just a quattro thing, be interested to hear other experiences. Inside rears also..

Perhaps they have some negative camber as standard ?

I've got this issue after lowering my air suspension via VCDS, but it gets serious when I drive in Dynamic mode all the time as this mean -20mm plus another -15mm (VCDS lowering) = -35mm of the zero value.

I assume all S8s have lower suspension than a standard D2, but I'm sure German fellas took this to consideration while setting up the camber and it's not normal that car would normally shred the tyres from inside as 'standard', or is it??

My feeling is it probably the control arm bushings starting to wear allow the weal to lean inwards slightly and over time its having an effect. Don't think i can be arsed to rebush it though but maybe i will if they not too pricey.

Im going to get it aligned again just to be sure something is not amiss on the toe out which could effect fronts as i did think both looked a wee bit toe out from standing at the front of it although thought it was just my eyes but now thinging perhaps i was correct, needs further investigation.

Yeah, but all 4 !?!? Are they wearing evenly??

I can say with certainty the front are both wearing on the inside shoulder. Rears are to slightly but i believe rear camber can be adjusted. Alignment aint my thing as dont have a machine to do it.

Fronts will wear more as these cars do have a tendency to scrub quite a bit on tight corners and car park manoeuvring.

Yep but its specifically inside shoulder wear on both that wouldn't be accounted for by that.

Could be down to suspension component wear or incorrect alignment.

When doing alignment make sure they do 'constant S' correctly as well. Most garages around here do not even know what it means when you ask them to make sure it's done. Not doing it correctly is a cause of tyre wear on many A4's, A's,A8s and Passat's.

Constant S ? I'm not familiar, thanks.

I have attached 2 pdf's about constant S.
http://forum.a8parts.co.uk/attachmen...1&d=1392484216

If you check the picture bolt 2 is adjustment bolt for constant s, garages most of the time fully tighten this bolt assuming that it is securing bolt causing constant s to be out. Normally this bolt is supposed to come out after adjustment and plastic protective cap to go in it's place. I have never seen it in practice and there is nothing wrong with leaving bolt in place as it's covered with thread lock and will not come out, it's just that it should not be fully tightened.

Thanks for the upload but i find it makes no sense tbh. I cant see why bolt 2 needs to be touched for toe adjustment and find Audi's workshop procedure (as is sometimes the case) for something simple very convoluted, but perhaps i am completely missing something!

You do TOE adjustment the usual way with track rod ends, after that you do constant S adjustment using bolt 2 to make sure TOE changes as it should when suspension goes up and down, then recheck normal TOE. If it's not done correctly TOE will be correct when car is stationary but could be wrong when car is loaded or when going over bumps and suspension travels up and down.

I can put up full adjustment procedure later.

I made a quick picture to show the idea. I have of course exaggerated the angles to better show the idea.

http://forum.a8parts.co.uk/attachmen...1&d=1392486758

Top picture shows the correct way, middle if the bolt 2 is tightened too little and bottom if it is tightened too much. In either of these cases you can adjust TOE to specifications while car is stationary and unloaded but when driving and suspension travels up and down it will change incorrectly.

Thanks for the drawing as it certainly helped explain something i had no idea about. As said, have no hands on alignment experience so this was useful + just re-read in ELSAWIN what you posted up. +++

There is nothing wrong with you not knowing. The problem is that many garages and technicians that change track rods and perform wheel alignment are not aware of this. They fully tighten bolt 2 when changing track rod end so you end up like bottom picture and then set TOE without adjusting constant S. So your TOE is correct when stationary and unloaded but changes by greater value then normal when loaded or when suspension is compressed over bumps and you end up with too much TOE-out in those conditions which result in inside edge tyre wear.