aceman

Guys -

I'm getting serious about pulling the trigger on a S8 as a daily driver. One issue of concern for me is the 21" wheels that the cars have w/ 35 series tires.

I have a BMW 550 with 40 series tires and in 5 years (100K miles), i've been had bubbles on appx 15 tires and gone through about 5-7 rims. Thankfully i had BMW's wheel and tire insurance (no deductable) before they changed the policies (now they limit total payout and have deductibles). Anyway - for those of you who put a lot of miles on your S8, how bad are those rims? are you going through a lot of wheels/tires?

Has anyone put, say 40 or 45 series tires on the car? any feedback?

Appreciate any help -

Thanks,

Aceman

MP4.2+6.0

Really depends on where you live/road conditions, and maybe pressures used to an extent.

I ran 275/35's on the D3 W12 (in the then 20" fitment; now 21) for 9 years and 100K miles. Bubbled only one near end of tire life--in a hard pothole hit I should have remembered from the past but forgot that one rainy night. Never bent a wheel in potholes or curbs and such. On both my D3 and now on D4 S8, those have been factory forged. S8 ones aren't, but then they are heavy too as far as strength. I migrated my D4 S8 down to 20's to get back to forged and weight loss, but really for feel and performance related to the pig weight of the 21's, not any worries about wheel bending and bubble stuff. The W12 many miles left me comfortable it would be fine. Air ride may also be a helpful factor, but not sure technically on that.

The S8 (and W12) also run somewhat more pressure for a given tire size relative to the A8 motors. Related to the HP, ultimate potential, etc. By the time you get to high 30's in plain English, that helps. Down in low 30's, definitely more risk from some older experiences. Don't know if you remember your 5 series pressures at all, plus were likely RFT's. Regardless, if you live somewhere with bombed out roads like a Detroit or rough winter conditions (also a Detroit...), you may be pretty vulnerable.

aceman

Thanks MP,

Yeah i'm in NJ and roads here depending on weather get crazy. I've had bubbles and bent rims on my 550ix Msport (usually 2-3 per year).

Aceman

eric strauss

Although we run our two S-cars hard in the canyons, the 35-series tires have been overly fragile - five tires destroyed on three cars over about 100K miles. I actually run 19's on my RS5 to save on tire costs (I get about 7-8K out of each set). Bigger wheels are beautiful jewelry, but they are heavy (in the worst place - unsprung weight) and actually reduce some metrics of performance. Wheels only need to be big enough to clear the brake calipers - so 18"s will fit on an S8. Although, the 20's are surely beautiful. If I got an S8 - I would likely order aftermarket from The Tire rack in minus-1 sizing. At least buy the Tire/Wheel insurance from Audi.

See the chart below on effects of upsized wheels on a VW Golf - diameter was, of course, held constant.

Happy Motoring

Eric

MP4.2+6.0

On same page about unsprung weight and all, and hence I changed mine downward to the OE forged 20s and took some out--9 pounds a corner as posted on in past. The UK brochures also list fuel economy specific to wheels now--required EU disclosure. 21's also cost between 1 and 2.5% on fuel economy per their #s...another post. You can expect that works back into acceleration a bit as well.

FWIW, the S8's and any other D4 w/ the 400mm fronts need 19+ wheels to clear. The D3 S8 (or W12 I had) could do 18, but just barely and those were 385mm.

Swissman564

Wow, this makes me grateful for our boringly flat & generally well maintained roads here on the Eastern Shore of MD.

eric strauss

Whenever there are no frost heaves, the roads do much better. I trashed many wheels in Massachusetts where I lived for thirty years. Then in SoCal, no ice, just random rocks in the roads from the canyon walls. In a 100 mile run, you are likely to dodge 30-50. You can bat .998 and still hit one every trip… rips the sidewall, so a patch doesn't work. That's why I carry a full size spare in my RS5's trunk - sort of a talisman to ward of evil ;-)

Ravill

Two years on my 21's and no probs.

Ritz

Road quality in the Peoples Republic of NJ is probably the worst I've seen in the developed world. I lost a couple of rims while living there myself. It's THAT bad.

I haven't had the same issue in Virginia where the roads are kept in a pretty good state of repair.

Best,

Y888

Downtown Chicago and around Detroit,worst potholes you can imagine.