Sep 22, 2018
@rum4mo Another pic.
Thanks for confirming that, that rear one must be at a similar height to the front one and in my mind serve the same purpose, which is to prevent paint work damage from flying debris. I might have misjudged the orientation of it when compared with the front one on your S4, by it must work okay "that way" round - unless the upper end has the same slopping/tapered profile, can you check up on that some time please. How that shape fits in with fitting rear mud flaps still remains a problem for me to get to grips with.
This could herald the start of many people buying in this new stone deflectors and retro fitting them to earlier/other cars to reduce stone damage further, okay earlier/other cars will not have the holes to accept them, but their is heavy duty double sided sticky tape available to hold them in place. The main issue for the front wheel arches I think, was that there is a section of wheel arch body work that is flat and folded in at right angles and used to support any mud flaps fitted, and it was that flat section mainly that required this extra protection, the rear wheel arches I think, don't have that folded section so maybe it is just the "thin" area and the body work behind that needs protecting when fitting wider wheels/tyres.
Edit:-maybe the rear mud flaps are fitted to a different way to the rear wheel arches, I have never fitted mud flaps to my S4 so can't comment on that - if so then that will be why the profile of these rear deflector is different.
Omfg this is painful it’s because of the shape of the rear arch and bumper it requires it to hide the tyre view. It’s nothing to do with stone chipping, as the rest of the arch would get chipped above and below it.
And it’s nothing to do with sales talk it’s just fact no guess work or the like required.
I had a good look at it on my Avant and it doesn't look like it suppose to be an extension to the body to hide the wheel. Looking directly from the top the wheel is hidden within the wheel arch. The plastic bit is virtually flash with the wheel arch anyway so it wouldn't add much width anyway.
Absolutely. That's why this remains a mystery to me. My wife's A4 doesn't seem to miss it.
Out of curiosity, what car do you have? I only ask because although you mention an S4 I don't imagine that you have a B9 S4 so that you can go take a look at them?
The front ones are longer and extend right to the bottom of the arch as I'd expect if you were trying to protect the paint from stones. The rear is all the way up where the bumper meets the arch so wouldn't protect the arch from stone damage anyway, not at the point where my B8.5 showed the most damage anyway. So your first sentence is wrong I'm afraid, the rear is nowhere near the same height as the front. I looked down at mine and that piece of plastic does in fact obscure part of the tyre that would otherwise be visible just where the bodywork starts to taper in behind it. Granted I don't think that you'd be able to see it without having spacers on, but it proves the theory.
Lastly, the interview about the Megane was with an engineer that worked on the car if I remember rightly, it wasn't just a sales guy. So, as an engineer, I will listen to the person who actually designed that specific part of the car and take his word for it.
These 'stone deflectors' have been around for years. I do not see anyone buying into them at all..
It is a B8 S4 that I have, hence the need for me to retro fit these stone deflectors to try to hold back any more damage to the rear folded section of the front wheel arches.
In respect of the extensions built into the Megane RS, I thought that I covered that quite clearly as yes they will be mainly functional, like they are on Focus RS when it reappears, I just happen to be an engineer as well so I do, like you question things until I find out the correct answer.
Remember one thing, even on that Megane RS, these extensions, in reality would not need to show as much as they do in relation to the general flow of the body work, but that is part and parcel of selling/styling a performance version of a car, just like comparing the performance version of an Audi S4 which as you know is an RS4 - difference boldly placed does improve the owner's feel good factor, and why not!
Yes this is going on a very long way for something as simple as stone deflectors, but if others are not interested in this thread they can avoid reading any new postings.
Edit:- sorry, I forgot to mention the point about the height of the rear stone deflectors, it looks like they are just covering "the area of concern" which on the rear wheel arches is the lowest section of the wheel arches which are metalwork, Audi probably does not bother about stone chipping occurring on the plastic bumper cover section - or the air flow at the rear of these cars means that is where a stone deflector is best placed to do its job.
I'm just wondering if you're thinking that the rears are in a different position than they're actually in is all? Do these stone guards for your car not fit at the bottom of the arch as you've described with the folded section? Rather than halfway up the arch where they won't actually help stone damage?
They're not really protecting much either since the only section that would be exposed if it isn't there is a 2mm thick bit of sheet metal that makes up the rear quarter.
Yes on the front, the stone deflectors end (at the bottom) maybe at the start of whatever is down there to protect the lower bodywork, which will be exactly where they are meant to be on the B8.5 S4 and probably where they are on your car - with coincides with covering the "folded wide section" and blending into the change in fold towards the top of the wheel arch where as you say the bodywork folds in on itself which the rear wheel arches have. Maybe Audi has discovered in trials, that even that 2mm folded back in section is prone to get stone chipped leading to paintwork/rusting warranty repairs.
I'm all for anything that does stop stone chipping, as long as it does not by its design bring with it a new dirt and water trap that causes some of the very issues it is meant to stop happening.
If you look at a car passing through water you see that the spray kicks up very high up the tyre as the tread displaces it from the road. I am not convinced these are actually stone guards at all but to reduce water spray..
Ok, so we're not really getting closer to determining the answer to what the OP was actually asking. Why are these trims (whatever they are) on an S4 but not on an A4?
I have them on my A4 so they aren't exclusive to the S4.
Mine was built in April 2016, so don't think they are to do with only later models having them.
The OP has compared 2 cars, both with 245 width tyres so may not be to do with tyre protrusion after all.
My A4 sits on the lowered sports suspension. Maybe this alters the position of the wheel in the arch sufficiently to require the trim if it is to do with tyre protrusion.
My A4 is quattro, as is the S4. Maybe the rear wheels being driven requires the trim if it is for stone deflection.
If it was for water spray reduction, wouldn't all cars have it?
Who has these bits of trim and who doesn't? What are the variables at play?
What wheels do you have on your car? If it has the wider versions/ones with lower offset it would support my thoughts I guess if compared to the standard wheels?
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I agree with you there, but I think "stone deflector" is maybe a better name than "debris deflectors" - so that is the name that car manufacturers tend to give them, sounds a lot better?
Remember, in general, where water ends up will be where most **** ends up, high density stuff like stones and lower density stuff like water, it is just that you normally don't ever witness the trajectory of stones being picked up by the tyres, you only ever see the damage that they have done some years down the line.
First plan might be to find them on a genuine version of Ekta that should show any limitation of use by PR code and/or age and/or Saloon/Avant.
So someone needs to start a posting with options listed and all others with B9 need to add their findings to it?
1) A4 A4 Q or S4 2)Saloon or Avant 3) Tyre size 4) ??? I am guessing that Audi are not factory fitting any unusual sized offset/widths that are raising a need for this.
I've got the 19" 5V spoke matt and diamond cut RS style alloys they are 8.5 inch width and ET40.
Also have sports suspension which is supposed to be 20mm lower than standard.
Yeah, so they’re wider than the standard wheels... It was mentioned before that with the stock wheels the pieces weren’t fitted.
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Are they not for 19" wheels and above? As in my links?
tbh, what you are saying makes perfect sense to me but rum4mo raises an alternative purpose and it would be good to be able to definitively rule it in or out.
So, who has a quattro A4 or S4 without these trims on the rear wheel arch and what is your wheel size?
Who has a non-quattro A4 with these trims on the rear wheel arch and what is your wheel size?
In both cases, what suspension do you have as well?
(The matters of great importance idle minds can find to discuss on the internet!)
I think you’ll find it hard to get someone with a non-Quattro S4...
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A very good point sir (careless copy & paste)! Edited accordingly
The strange thing is, for these "attachments" in that parts listing, the limitation of use is "J" and PR-HZ1 for the top front one, and PR-HZ1 for the rear one, "J" just means Japan market, and PR-HZ1 is listed for extremely small tyres/wheels which does not make much sense unless PR-HZ1 now means something entirely different like extra wide wheels, but it looks like Audi have changed the offset if offering wider rims, which makes sense as the wheels must always clear the suspension uprights, clear the callipers and stay clear of the outer bodywork.
Finding a proper copy of Ekta for this age of cars should help as far as limitations of use are concerned.
Can we with idle/wasted minds try to get this one to 3 pages?
I'm not sure that I had any other valid purposes other than to protect the car from road "stuff" flying around and damaging the body work - and with wider and probably larger diameter wheels/tyres would be a good enough reason to fit them only to some cars - ie dependant on how they were kitted out at the initial build. So maybe I'm helping closing down the chances of us making this one to 3 pages?
@Filipão, Well done if you were looking for a simple answer. Even better query than your seeking a quieter S4 ;-)
I have an A4 quattro with 19's.
I also have these plastic parts.
I don't really care what they're for or what the correct name for them is.
I'm with Grumpz, except my car isn't quattro.
I also stick by what I said back in post 2 (legislation around wheels/tyres in relation to bodywork) and what others have confirmed already.
Amazed some are still trying to find a different explanation.
I'm not attempting to find a different explanation if you were referring to me, there have been 4 other posters that seem to have a different view on the purpose of them so wanted to find out what the determining feature was for these to be present.
Anyway, it's a forum on the internet, the home of trivial discussions. Might have to start a thread comparing the flash frequency of the red LED on the top of the drivers door. I'm sure mine's trying to communicate with me in morse code.
I think they are being made more technical by some than for what they're intended....
All good stuff, where is the beginning of page 3?
Working on it, see section 2 here http://www.legislation.gov.uk/uksi/1986/1078/regulation/63/made:
"Subject to paragraphs (3) and (5), every vehicle to which this regulation applies shall be equipped with wings or other similar fittings to catch, so far as practicable, mud or water thrown up by the rotation of its wheels or tracks. "
The vehicles this applies to include heavy motor cars, motor cars and motor cycles, not being agricultural motor vehicles or pedestrian-controlled vehicles.
As I stated before, they are to reduce, or prevent, spray from wider wheels.
That reason is completely devastating, no stopping body work damage, just pedestrian annoyance! Pity the regs don't stop cars splashing pedestrians instead of relying on laws to get you if/when you are reported for causing splashing, I'm not guilty more I've been splashed due to useless road drainage!
Oh boy, oh boy...
The answer was there, just over complicated it seems...
Separate names with a comma.