Help me choose a 20" wheel for my S8....
07-23-2016, 10:59 AM
#14
AudiWorld Super User
#3 is the RS alternate version of the "normal" twin 7's used on some A7's/S7's, and maybe earlier D4 A8's. Actual wheel is found on RS7's and C7 RS6's but rare here. RS version is a 20 x 9 ½ with a very aggressive offset; would want to be careful on that in a D4 fitment. The "normal" twin 7 is more common, though not on current USA production vehicles so hard to find as takeoffs. Was also used on D3 A8's with 20 x9 fitment in the more common form. It was not the D3 S8 wheel, which was cast.
Wheel 3, like wheel 2, is likely a Fuchs forged wheel, but it has to be the "right" one. In various wheels, Audi sort of copies them in cheaper cast versions. If the sizing is stamped into the wheel usually around the hub, it should be forged. Polished, brushed or machined face to spokes is another clue, which these have. If sizing cast into the mold on the inside of a spoke, and especially if it is branded Speedline or Ronal that is also cast in to the inside of the spokes, wheel in general is cast. Makes a meaningful difference in weight as well as general strength.
Wheel 3, like wheel 2, is likely a Fuchs forged wheel, but it has to be the "right" one. In various wheels, Audi sort of copies them in cheaper cast versions. If the sizing is stamped into the wheel usually around the hub, it should be forged. Polished, brushed or machined face to spokes is another clue, which these have. If sizing cast into the mold on the inside of a spoke, and especially if it is branded Speedline or Ronal that is also cast in to the inside of the spokes, wheel in general is cast. Makes a meaningful difference in weight as well as general strength.
07-23-2016, 06:27 PM
#15
AudiWorld Member
Thread Starter
#3 is the RS alternate version of the "normal" twin 7's used on some A7's/S7's, and maybe earlier D4 A8's. Actual wheel is found on RS7's and C7 RS6's but rare here. RS version is a 20 x 9 ½ with a very aggressive offset; would want to be careful on that in a D4 fitment. The "normal" twin 7 is more common, though not on current USA production vehicles so hard to find as takeoffs. Was also used on D3 A8's with 20 x9 fitment in the more common form. It was not the D3 S8 wheel, which was cast.
Wheel 3, like wheel 2, is likely a Fuchs forged wheel, but it has to be the "right" one. In various wheels, Audi sort of copies them in cheaper cast versions. If the sizing is stamped into the wheel usually around the hub, it should be forged. Polished, brushed or machined face to spokes is another clue, which these have. If sizing cast into the mold on the inside of a spoke, and especially if it is branded Speedline or Ronal that is also cast in to the inside of the spokes, wheel in general is cast. Makes a meaningful difference in weight as well as general strength.
Wheel 3, like wheel 2, is likely a Fuchs forged wheel, but it has to be the "right" one. In various wheels, Audi sort of copies them in cheaper cast versions. If the sizing is stamped into the wheel usually around the hub, it should be forged. Polished, brushed or machined face to spokes is another clue, which these have. If sizing cast into the mold on the inside of a spoke, and especially if it is branded Speedline or Ronal that is also cast in to the inside of the spokes, wheel in general is cast. Makes a meaningful difference in weight as well as general strength.
Will the 35mm vs 37mm offset be an issue on my s8? It would mean just a 2mm outboard right?
07-23-2016, 07:51 PM
#16
AudiWorld Super User
Correct, basically just rounding error. On 2015 S8 I run the ET37 20 x9 with 275/40-20. Spaced 12mm rear, which is about the max. Thus 2 is easy. In front I see about 5-8mm ideally and 10 is a bit much; again 2mm more would be easy and actually even a bit more dialed in than at 37. If you chose to run 265/40's, the nominal tire width difference also exceeds the offset change. Presumably you have 275/35-21's now (on ET37's).
07-24-2016, 01:22 PM
#17
AudiWorld Member
Thread Starter
Correct, basically just rounding error. On 2015 S8 I run the ET37 20 x9 with 275/40-20. Spaced 12mm rear, which is about the max. Thus 2 is easy. In front I see about 5-8mm ideally and 10 is a bit much; again 2mm more would be easy and actually even a bit more dialed in than at 37. If you chose to run 265/40's, the nominal tire width difference also exceeds the offset change. Presumably you have 275/35-21's now (on ET37's).
07-24-2016, 04:03 PM
#18
AudiWorld Super User
Well, I kinda know why you might be asking that... I wouldn't. A lot more below if interested, at least the various nuances I worked through. More so perhaps coming from that exact size on my D3.
It is the tire size that fits the S7, not the D4 A8/S8. Basically it is up to an inch in diameter too small (0.6-1.0") depending on which exact tire size you go with among the ones in the zone. That tire is also the one used on D3's with the optional 20" wheels, except the D3 S8 that used a 265.
Is it going to break? No. If you are running 275/35 21's now, you are running a 28.5" diameter. TR says for one tire I looked at anyway, it does 732 revs/mile. Found 747 and 752 revs per mile for a couple of the 275/35 20's. Call it 750. That means about 2 ½ percent of optimistic speedo error. On my S8 starting at 275/35-21 and going to 275/40-20, I went from about 1mph optimistic to essentially dead on at U.S. cruising speeds using a GPS app. Thus, you might end up at 3 or 4 optimistic. End of the world, no, but a consideration.
Maybe more important, at least to me, was specifically the S8 just didn't feel quite sorted exactly right when I first got it. Some of it takes getting used to, but just about that same comment is probably in any decent review I have read about the S8 when the test ride has the 21's, which they generally did. And I think it is probably a combo of the stiffer ride of the S8 suspension set up, married to the 21's and 35 profile. Some of it is in the piggish 21" cast wheel and tire weight (7-10 pounds heavier than the best OE forged set ups in 20, per wheel), but I think some of it is in the profile relative the the D4 S8 suspension calibration. Also to be clear, I'm not looking for a cushy soft ride either. I drove my D3 W12 for 100K fun miles with 275/35's, and I even installed the D3 S8 sway bars to firm it up, and late on the supposedly slightly stiffer upper control arm bushings. Some with A8's used to complain about the 20" ride feel and sometimes even the 19's, but I was not among them. Might have been among the reasons though they stepped up the profile to 40's with the D4. The D3 A8 also had the non sport air ride units that are either one or two notches away from the S8 units in terms of ride firmness. All that said, if you like stiffness on ride now in a variety of conditions, 275/35 will be just about the same in 20's and 21's assuming same performance type summer tire. But you will lose a bunch of 21" unsprung rotating weight (the absolute worst of vehicle pork) if you go with one of the OE 20 forged wheels.
Objectively, you will also be effectively dropping the car at the same time by 0.4," which at least for me with its leading and very low chin is not real world practical. It is already something I have to watch and think about on low street swales and driveway entrances as well as curb and concrete block stop parking. Handing the car lowered another 0.4" or more to the wife or someone else not familiar with it seems like a recipe for problems in my world.
For what it's worth, the car does look a little better to me as far as the tires themselves in 21's than 20's. Totally subjective though. The 275/40's start to look just a little "cop car-ish" bulge wise. 21's with the 275/35's didn't look like that, just like my D3 275/35's didn't. All were/are 9" wheels too. 265's that are the norm would clean that sidewall look up a little bit perhaps. 20's in general show brakes better I think, while even with their ginormous size they get a little lost inside the 21's. In using a 275/40 I picked up a bit of diameter/radius for the overall wheel with mounted tire (+ .2" diameter, vs. losing 0.8" or more). That will be somewhat noticeable as far as fender reveal if subjective looks matter, plus gives me a tint bit more real world ride height at same time.
Again, it won't break, but I would use a size in the D4 zone. As between 265 and 275 (in 40's), that is also very specific as to which exact tire you want, if you have preferences. Some are in one size, some in the other. Almost none in both. There are more 275/35 choices as I know from my D3 A8 W12, but in moving to D4 even with a bunch of wheel and tire sets I unloaded them. It's getting a little better, but honestly the range of choices in the 265 20s is pretty **** poor, and Audi did no one (...other than their tire partners as they were negotiating price...) any favors in using a then non standard size. When I look at take offs now, I look for bare wheels if possible, Or D4 specific where I could use the tires directly--but those are mostly the twin 10 spokes as far as the available market. Or I just figure I won't run/use the tires if it is a set of S7/A7 wheels and price needs to be better and/or wheels pretty unique to interest me.
It is the tire size that fits the S7, not the D4 A8/S8. Basically it is up to an inch in diameter too small (0.6-1.0") depending on which exact tire size you go with among the ones in the zone. That tire is also the one used on D3's with the optional 20" wheels, except the D3 S8 that used a 265.
Is it going to break? No. If you are running 275/35 21's now, you are running a 28.5" diameter. TR says for one tire I looked at anyway, it does 732 revs/mile. Found 747 and 752 revs per mile for a couple of the 275/35 20's. Call it 750. That means about 2 ½ percent of optimistic speedo error. On my S8 starting at 275/35-21 and going to 275/40-20, I went from about 1mph optimistic to essentially dead on at U.S. cruising speeds using a GPS app. Thus, you might end up at 3 or 4 optimistic. End of the world, no, but a consideration.
Maybe more important, at least to me, was specifically the S8 just didn't feel quite sorted exactly right when I first got it. Some of it takes getting used to, but just about that same comment is probably in any decent review I have read about the S8 when the test ride has the 21's, which they generally did. And I think it is probably a combo of the stiffer ride of the S8 suspension set up, married to the 21's and 35 profile. Some of it is in the piggish 21" cast wheel and tire weight (7-10 pounds heavier than the best OE forged set ups in 20, per wheel), but I think some of it is in the profile relative the the D4 S8 suspension calibration. Also to be clear, I'm not looking for a cushy soft ride either. I drove my D3 W12 for 100K fun miles with 275/35's, and I even installed the D3 S8 sway bars to firm it up, and late on the supposedly slightly stiffer upper control arm bushings. Some with A8's used to complain about the 20" ride feel and sometimes even the 19's, but I was not among them. Might have been among the reasons though they stepped up the profile to 40's with the D4. The D3 A8 also had the non sport air ride units that are either one or two notches away from the S8 units in terms of ride firmness. All that said, if you like stiffness on ride now in a variety of conditions, 275/35 will be just about the same in 20's and 21's assuming same performance type summer tire. But you will lose a bunch of 21" unsprung rotating weight (the absolute worst of vehicle pork) if you go with one of the OE 20 forged wheels.
Objectively, you will also be effectively dropping the car at the same time by 0.4," which at least for me with its leading and very low chin is not real world practical. It is already something I have to watch and think about on low street swales and driveway entrances as well as curb and concrete block stop parking. Handing the car lowered another 0.4" or more to the wife or someone else not familiar with it seems like a recipe for problems in my world.
For what it's worth, the car does look a little better to me as far as the tires themselves in 21's than 20's. Totally subjective though. The 275/40's start to look just a little "cop car-ish" bulge wise. 21's with the 275/35's didn't look like that, just like my D3 275/35's didn't. All were/are 9" wheels too. 265's that are the norm would clean that sidewall look up a little bit perhaps. 20's in general show brakes better I think, while even with their ginormous size they get a little lost inside the 21's. In using a 275/40 I picked up a bit of diameter/radius for the overall wheel with mounted tire (+ .2" diameter, vs. losing 0.8" or more). That will be somewhat noticeable as far as fender reveal if subjective looks matter, plus gives me a tint bit more real world ride height at same time.
Again, it won't break, but I would use a size in the D4 zone. As between 265 and 275 (in 40's), that is also very specific as to which exact tire you want, if you have preferences. Some are in one size, some in the other. Almost none in both. There are more 275/35 choices as I know from my D3 A8 W12, but in moving to D4 even with a bunch of wheel and tire sets I unloaded them. It's getting a little better, but honestly the range of choices in the 265 20s is pretty **** poor, and Audi did no one (...other than their tire partners as they were negotiating price...) any favors in using a then non standard size. When I look at take offs now, I look for bare wheels if possible, Or D4 specific where I could use the tires directly--but those are mostly the twin 10 spokes as far as the available market. Or I just figure I won't run/use the tires if it is a set of S7/A7 wheels and price needs to be better and/or wheels pretty unique to interest me.
Last edited by MP4.2+6.0; 07-24-2016 at 05:03 PM.
07-25-2016, 09:29 AM
#19
AudiWorld Member
Thread Starter
Well, I kinda know why you might be asking that... I wouldn't. A lot more below if interested, at least the various nuances I worked through. More so perhaps coming from that exact size on my D3.
It is the tire size that fits the S7, not the D4 A8/S8. Basically it is up to an inch in diameter too small (0.6-1.0") depending on which exact tire size you go with among the ones in the zone. That tire is also the one used on D3's with the optional 20" wheels, except the D3 S8 that used a 265.
Is it going to break? No. If you are running 275/35 21's now, you are running a 28.5" diameter. TR says for one tire I looked at anyway, it does 732 revs/mile. Found 747 and 752 revs per mile for a couple of the 275/35 20's. Call it 750. That means about 2 ½ percent of optimistic speedo error. On my S8 starting at 275/35-21 and going to 275/40-20, I went from about 1mph optimistic to essentially dead on at U.S. cruising speeds using a GPS app. Thus, you might end up at 3 or 4 optimistic. End of the world, no, but a consideration.
Maybe more important, at least to me, was specifically the S8 just didn't feel quite sorted exactly right when I first got it. Some of it takes getting used to, but just about that same comment is probably in any decent review I have read about the S8 when the test ride has the 21's, which they generally did. And I think it is probably a combo of the stiffer ride of the S8 suspension set up, married to the 21's and 35 profile. Some of it is in the piggish 21" cast wheel and tire weight (7-10 pounds heavier than the best OE forged set ups in 20, per wheel), but I think some of it is in the profile relative the the D4 S8 suspension calibration. Also to be clear, I'm not looking for a cushy soft ride either. I drove my D3 W12 for 100K fun miles with 275/35's, and I even installed the D3 S8 sway bars to firm it up, and late on the supposedly slightly stiffer upper control arm bushings. Some with A8's used to complain about the 20" ride feel and sometimes even the 19's, but I was not among them. Might have been among the reasons though they stepped up the profile to 40's with the D4. The D3 A8 also had the non sport air ride units that are either one or two notches away from the S8 units in terms of ride firmness. All that said, if you like stiffness on ride now in a variety of conditions, 275/35 will be just about the same in 20's and 21's assuming same performance type summer tire. But you will lose a bunch of 21" unsprung rotating weight (the absolute worst of vehicle pork) if you go with one of the OE 20 forged wheels.
Objectively, you will also be effectively dropping the car at the same time by 0.4," which at least for me with its leading and very low chin is not real world practical. It is already something I have to watch and think about on low street swales and driveway entrances as well as curb and concrete block stop parking. Handing the car lowered another 0.4" or more to the wife or someone else not familiar with it seems like a recipe for problems in my world.
For what it's worth, the car does look a little better to me as far as the tires themselves in 21's than 20's. Totally subjective though. The 275/40's start to look just a little "cop car-ish" bulge wise. 21's with the 275/35's didn't look like that, just like my D3 275/35's didn't. All were/are 9" wheels too. 265's that are the norm would clean that sidewall look up a little bit perhaps. 20's in general show brakes better I think, while even with their ginormous size they get a little lost inside the 21's. In using a 275/40 I picked up a bit of diameter/radius for the overall wheel with mounted tire (+ .2" diameter, vs. losing 0.8" or more). That will be somewhat noticeable as far as fender reveal if subjective looks matter, plus gives me a tint bit more real world ride height at same time.
Again, it won't break, but I would use a size in the D4 zone. As between 265 and 275 (in 40's), that is also very specific as to which exact tire you want, if you have preferences. Some are in one size, some in the other. Almost none in both. There are more 275/35 choices as I know from my D3 A8 W12, but in moving to D4 even with a bunch of wheel and tire sets I unloaded them. It's getting a little better, but honestly the range of choices in the 265 20s is pretty **** poor, and Audi did no one (...other than their tire partners as they were negotiating price...) any favors in using a then non standard size. When I look at take offs now, I look for bare wheels if possible, Or D4 specific where I could use the tires directly--but those are mostly the twin 10 spokes as far as the available market. Or I just figure I won't run/use the tires if it is a set of S7/A7 wheels and price needs to be better and/or wheels pretty unique to interest me.
It is the tire size that fits the S7, not the D4 A8/S8. Basically it is up to an inch in diameter too small (0.6-1.0") depending on which exact tire size you go with among the ones in the zone. That tire is also the one used on D3's with the optional 20" wheels, except the D3 S8 that used a 265.
Is it going to break? No. If you are running 275/35 21's now, you are running a 28.5" diameter. TR says for one tire I looked at anyway, it does 732 revs/mile. Found 747 and 752 revs per mile for a couple of the 275/35 20's. Call it 750. That means about 2 ½ percent of optimistic speedo error. On my S8 starting at 275/35-21 and going to 275/40-20, I went from about 1mph optimistic to essentially dead on at U.S. cruising speeds using a GPS app. Thus, you might end up at 3 or 4 optimistic. End of the world, no, but a consideration.
Maybe more important, at least to me, was specifically the S8 just didn't feel quite sorted exactly right when I first got it. Some of it takes getting used to, but just about that same comment is probably in any decent review I have read about the S8 when the test ride has the 21's, which they generally did. And I think it is probably a combo of the stiffer ride of the S8 suspension set up, married to the 21's and 35 profile. Some of it is in the piggish 21" cast wheel and tire weight (7-10 pounds heavier than the best OE forged set ups in 20, per wheel), but I think some of it is in the profile relative the the D4 S8 suspension calibration. Also to be clear, I'm not looking for a cushy soft ride either. I drove my D3 W12 for 100K fun miles with 275/35's, and I even installed the D3 S8 sway bars to firm it up, and late on the supposedly slightly stiffer upper control arm bushings. Some with A8's used to complain about the 20" ride feel and sometimes even the 19's, but I was not among them. Might have been among the reasons though they stepped up the profile to 40's with the D4. The D3 A8 also had the non sport air ride units that are either one or two notches away from the S8 units in terms of ride firmness. All that said, if you like stiffness on ride now in a variety of conditions, 275/35 will be just about the same in 20's and 21's assuming same performance type summer tire. But you will lose a bunch of 21" unsprung rotating weight (the absolute worst of vehicle pork) if you go with one of the OE 20 forged wheels.
Objectively, you will also be effectively dropping the car at the same time by 0.4," which at least for me with its leading and very low chin is not real world practical. It is already something I have to watch and think about on low street swales and driveway entrances as well as curb and concrete block stop parking. Handing the car lowered another 0.4" or more to the wife or someone else not familiar with it seems like a recipe for problems in my world.
For what it's worth, the car does look a little better to me as far as the tires themselves in 21's than 20's. Totally subjective though. The 275/40's start to look just a little "cop car-ish" bulge wise. 21's with the 275/35's didn't look like that, just like my D3 275/35's didn't. All were/are 9" wheels too. 265's that are the norm would clean that sidewall look up a little bit perhaps. 20's in general show brakes better I think, while even with their ginormous size they get a little lost inside the 21's. In using a 275/40 I picked up a bit of diameter/radius for the overall wheel with mounted tire (+ .2" diameter, vs. losing 0.8" or more). That will be somewhat noticeable as far as fender reveal if subjective looks matter, plus gives me a tint bit more real world ride height at same time.
Again, it won't break, but I would use a size in the D4 zone. As between 265 and 275 (in 40's), that is also very specific as to which exact tire you want, if you have preferences. Some are in one size, some in the other. Almost none in both. There are more 275/35 choices as I know from my D3 A8 W12, but in moving to D4 even with a bunch of wheel and tire sets I unloaded them. It's getting a little better, but honestly the range of choices in the 265 20s is pretty **** poor, and Audi did no one (...other than their tire partners as they were negotiating price...) any favors in using a then non standard size. When I look at take offs now, I look for bare wheels if possible, Or D4 specific where I could use the tires directly--but those are mostly the twin 10 spokes as far as the available market. Or I just figure I won't run/use the tires if it is a set of S7/A7 wheels and price needs to be better and/or wheels pretty unique to interest me.
I ordered them.
You were right - they're forged, meaning they're much stronger and MUCH lighter than the cast wheels and were an option on the RS7. They're about $6K new, so at $1700 they were a decent bargain!
I will be using them as my winter wheel set!
BTW What snow tires do you recommend?
07-25-2016, 01:43 PM
#20
AudiWorld Super User
Hey thank you so much.
I ordered them.
You were right - they're forged, meaning they're much stronger and MUCH lighter than the cast wheels and were an option on the RS7. They're about $6K new, so at $1700 they were a decent bargain!
I will be using them as my winter wheel set!
BTW What snow tires do you recommend?
I ordered them.
You were right - they're forged, meaning they're much stronger and MUCH lighter than the cast wheels and were an option on the RS7. They're about $6K new, so at $1700 they were a decent bargain!
I will be using them as my winter wheel set!
BTW What snow tires do you recommend?
Have run those and the predecessors for years on my Audis. More a performance winter than some others, which also probably fits w/ S8. All has a V speed rating which fits the vehicle. I am in CA so 90% of my winter driving is not actually on any snow, ice or near freezing temps. They are manageable as such noise and fine cornering wise for everyday dry (or rainy) driving. But they also work well in heavy Tahoe snow dumps and icy roads and slopes for days after; different league than a lot of mediocre A/S's w/ AWD. In the 275/40's you can get the Pirelli Sottozero's that are similar to the Dunlops; I ran those on D3 W12 since there was no Dunlop fitment for it. Pretty similar snow, ice, noise, performance and wear wise to the Dunlops for me, but they cost more. In 275's, there are a variety of more aggressive snow tires too, including some Blizzaks, if you are in tougher winter conditions. A lot are nominally SUV tires, but some are fit on higher performance ones. The V rating is sort of a clue, like various other Pirellis.
Last edited by MP4.2+6.0; 07-25-2016 at 07:03 PM.