hunterp27

Gang,

The S8 needs new shoes. I have read as much as I can regarding the sizing required for the D3 S8 and I have found a lot of info on people wanting to go with more width such as a 275 cross section. My question is this: I would like to go with a shorter sidewall....a 30% versus 35%. Other than a harsher ride and throwing the speedo off a tad, are there any negatives that anyone knows of? I am leaning towards Michelin Pilot Super Sport which I can get all 4 for 1200 bucks. The 35 series are 1500 Thoughts/Input???

Hunter

mishar

Other than a harsher ride and throwing the speedo off they would look too small for those wheel wells and burn more fuel. Why don't you go for 275/35x20 Continental ExtremeContact DW for $864. They are great tires.

MP4.2+6.0

Yes, you are thinking the right sort of issues. I think few end up going down to 30's though, unless they are going up to 21's. You identify the obvious ride and speedo issues. Since I have 20's on my W12 as factory in 275/35-20, I know that running diameter (27.7") is already a better set up for speedo issues, at least on mine where I have cross checked it with handheld GPS. You are at 27.3" at 265/35, and will fall off from there with 30's. Factory 18's and 19's for 4.2's or lower line W12's are down at 27.0, with presumably incrementally more error.

Another technicality; if you lower the running circumference meaningfully, you are also changing the gearing effectively. Certainly an old trick and slightly modified road course type idea, though when done there its often the smallest and lightest wheel that will clear the brakes and then also pulls down unsprung weight. Remember someone doing it with a tracked D2 S8--which they reported back was fun but a total pig still. That also means a bit less MPG. Since on the W12 I have more power than needed 99.9% of the time, I would take a few more % MPG's instead of 1/10 off.

BUT, I think what you may not have looked at is load rating. All D3's are porkers, as are most every Audi made. You've got about 4500 pounds of pork; I've got 4700. Look at your load sticker on the car (likely front drivers door jamb by 2007; was on tank lid earlier). The 265/30 in SuperSport is an XL rated tire (good for pork), but its only 94Y. That seems way down on a D3 to me. I run 102 in most any tire I have bought, and I think in any W12 possible size, about the lowest the factory spec goes is about 99. The most common S8 tire I used to see when they were new was the Yoko Advan Sport. Those are 99 rated in the 265/35's. Be careful here and don't mount substandard load rated tires. The SuperSports are a great tire--I ran their predecessor PS2's on the W12 in 275/35 and run the SS's on my Mini S today--but it may be a wrong choice in this sizing on a D3. In 275/35, no worries load wise. I see they are in 265/35 too, but you likely need the higher 99Y XL ones, not the 95Y ones.

More generally, as you go down to 30's I bet you will be skating on the load rating issue almost no matter what. Just not much sidewall there. If it were mine, I would do either factory 265's in 35's, or the factory 275/35-20s for every other D3 besides the S8. The whole 265 size grouping itself is kind of an oddball. When the S8 first came out selections were more limited, but still not nearly what is found with 275's. Both more choices and more price points to choose among if you go to 275.

Finally, if you go SuperSport, be sober that you are looking at 20K miles before they are basically toast. All I saw on the PS2's. Same with the Dunlop summers I run now. The performance summers will only get to those kinds of miles. It's not the "sport side" per an S8, but if cost per mile and frequency of new tires is meaningful, you would want to look at performance A/S's. Having been with performance summers (and dedicated snows) most of my W12's life, the next tire set I buy will be the Michelin AS3's. By all accounts, even as an A/S they have a legit. claim to say they perform at the level of many summers. You may only see 30K miles with the pork and the HP, but still better than 20K and at no meaningful price delta in general.

TSHong

+1 with what mp4 have already posted. One other thought is with 30 series tires you will incrementally be more susceptible to damaging your tire and wheels when you hit a pothole. You might drive on perfect roads but I run a chain of tire and auto service facilities and I see it every day.

volvopentaman

I run 275/40R20 on my W12L 2008 with ceramic brakes and the forged factory rims.

Totally great combination, i drove the car from Vilnius in Lithuania to Tallin in estonia, 600km of **** roads. Was able to pull incredible speeds on harsh roads with the car, without having to fear for the rims. With 30% wheels the same trip would have taken hours longer, because of the really bad roads. The speedo is a bit off tough, shows 1-3km/h too small readings compared to GPS.

I wonder if the speedo is adjustable By VCDS or Audi VAS?

mishar

Speedometer can't be adjusted by VCDS/VAS. May be some other more powerful software. ABRITES?

Deeper sidewall will protect your rims, but not your air suspension.

MP4.2+6.0

just w/ the ceramics. A delta we don't see here in N.A.

hunterp27

OK, the more research I do the more confused I get. I appreciate all of the input thus far and this thread could have easily gone in the tire and wheel section but I chose to place it here given the weight of the D3 platform requiring somewhat particular knowledge for tires. So, a little more info about what I like and the road conditions in my area, as well as the options I am considering:

- I live in Dallas and we have generally pothole free/frost-heave free roads here. Most of the roads here are either new or concrete which are both good with regard to potholes. So, road conditions are not a major concern.
- I am going to keep the 20 inch OEM rims which are pretty strong from what I can tell
- I tend to lean toward the shorter sidewall purely for aesthetics, hence the reason for my Original post. Just like the way it looks better. To each his own.........right???
- Road noise is a concern to me as I don't like the cabin to be filled with howling tires that are designed for the track.. The Yoko ADVANs that are on it now are very loud and it seems like others have complained about this issue here and in other car/tire forums.

So, back to the original question sorta. Given that the 265/35/20 Yoko's that came as standard issue have a much larger tread width and cross section than most tires offered in the 275 range, I have determined that moving to the 275's is the right place. It widens the options in terms of Manufacturers, tread choices and prices. Typically when you have a wider pool of options, you will find the right combo of price, performance, brand, noise, treadwear and so forth. Now the questions becomes, can I ride on a 30 series tire in the 275 category safely? Most all of these have a rating in the 97Y (1609 pounds) range. I know the car states that its requires a 99Y rating but I cannot imagine that the minuscule difference will make that big of a deal given the amount of over engineering that's built into tires and these cars. Here are the tires under consideration:

1. Michelin Super Sport 275/30/20 $285.00 each (great price)
2. Continental DWS 275/30/20 $216.00 each (wish the DW still came in this size)
3. Toyo Proxes T1S 275/30/20 $212.00 each (awesome quiet tire for the money, had them on my M5
4. Pirelli P Zero 275/35/20 $192.00 each (outlier due to 35 versus 30)
5 Continental DW 275/35/20 $216.00 each (outlier #2 due to 35 versus 30)

Lots to think about. If I can get comfortable with the load issue, I will likely buy the Michelins given their overall reputation, past experience and the great deal on these. Yes, I do understand that mileage longevity varies widely among all these tires and is a consideration, but I'm resigned to the fact that I change tires every 18-24 months no matter what. All of these will do that for me. As usual, I welcome any input here from all the trusted members of this forum. Thanks in advance and I look forward to everyone chipping in.
Hunter

MP4.2+6.0

I basically don't agree it is a safe or relatively trouble free choice to go down to 30's. If you want to study it more, probably the thing to do is look for any posts w/ 21's on the D3, since those would usually be 30's. On the D4, because they went back up to 40's on the 20's, you still only find 35's on the 21's IIRC. There is one clue to me--from the factory as the car evolved.

You are correct BTW on the 265 abnormally large width. Supposedly all Yoko did was take a 275 carcass and cut down the side wall. Not uncommon in tires that two adjoining sizes may sometimes share essentially the same tread width.

More on the safety and longevity: besides the tires, also consider the suspension, particularly the front. Cutting through all the b.s., I think for all it's sophistication, the suspension is under spec'ed on the D3 already. Fundamentally it is an A4 genesis design from the late 90's which then spread to the D2 A8 and C5 A6. Put aside the air units that plush out the ride, keep it level and presumably help with dive and squat. The core arm set up, bearings, bushings, etc. are quite similar to the others. But of course the A8/S8 doesn't weigh like any version of the A4 of the era, and the S8 (and W12) motors both pork up the front end way more than A4's or even 4.2 A8's. And worse, your car (like mine) has the heaviest possible brakes. You have 39 pound rotors alone on each front wheel. An A4 wheel and tire all in was probably sub 50 pounds. IIRC ours are more like 65-70 pounds, and you probably have 20+ more pounds of total braking hardware compared to the later smaller designs once they got to aluminum based calipers like the D3 has. Candidly on an S8, you don't have terribly light wheels within the OE 20 group either, nor necessarily the strongest. Those are cast; the "old style" and "new style" RS4/RS6 design wheels (nine spoke and then twin 7's) are the forged ones, with the twin 7's about 5 pounds less than the 9 spokers--those were found in both flavor on the W12's and the twin 7's on the later A8 sport package ones. Meantime, the air units can plush out the ride, but the beating is still happening at each suspension component, and with this combined mega dose of unsprung weight (massive tires, big wheels, not forged, big honkin' conventional brakes). We already know the front upper arms are probably now the identifiable weakest link on the whole D3 that seemingly everyone runs into over time. So, the 30's would take out another good fraction of an inch of the very limited sidewall here, and on top of that you end up under the load rating. If anything, tire load ratings probably need to go UP as you drop the sidewall, not merely stay the same.

What I would do instead if you want a powerful "look" is 1) do the VAG COM mod to the suspension, 2) run spacers. Drop it another 10+ mm. Since the tire diameter will stay larger (and yet .4" more w/ 275's), you will ride barely lower than before, yet close up a combined .6" or so of wheel well gap compared to now. Then run some spacers--12mm in front and 20mm in back on OE 20's in 275--and you will end up with very buttoned down look.

hunterp27

MP4.2+6.0,

First off, thank you very much for all the knowledge regarding these very idiosyncratic automobiles. I talked with TireRack today and they have convinced me that running the 30 series is not that great of an idea, but not from a safety standpoint. Once we went thru the numbers for the gross weight for each axle, the 97 rated tires can easily cover the weight for the car at 1609 pounds per corner with extra room to spare. The more salient issue seems to be the rolling circumference related to what the computer is calibrated to be looking for. I am sure that this is probably addressable thru the VAG COM, but I'd rather not have to jack with any of that. I'm just gonna go with a 275/35/20 and call it a day. Now I have to decide between these three tires:

1. Michelin Super Sport
2. Conti DW
3. Toyo Proxes T1-S

Hunter