JD15

This version of the adjustable suspension arguably degrades performance but improves comfort.

adg44

That is incorrect. This is the ideal performance setup.

JD15

A suspension with soft compromised springs is the ideal performance setup? Based on current information, this adjustable suspension is similar to that of the B8 S4, which was inferior to the fixed suspension for spirited driving. Unfortunately, this is not a suspension with magnetorheological dampers.

adg44

You'll just have to trust me.

This is not the comfort adaptive suspension, and it is not the B8 setup.

And you have a different spring rate with th adaptive dampers because this then allows the dampers to do their work.

The S Sport package with 18" wheels and Dynamic steering is your ideal performance setup.

Glisse

The ZF Sachs CDC system's primary role is chassis control, not comfort.

Plenty of current information out there to clarify the systems are very different. Read up on the new centralised chassis control system used on the B9 platform, too. An S3 uses mag dampers. Audi tend to use them with Haldex based quattro systems, the R8 uses them too.

US already has the "soft" version of adaptive suspension - should be possible to drive back to back with the standard passive suspension and see if you find the spring/damper rates feel unbalanced in either Comfort or Dynamic on the adaptive system vs the passive.

BMW's current M3/M4 use previous generation ZF Sachs CDC dampers on their Adaptive Drive option. Lots of discussion on BMW forums if interested in how owners view it vs passive.

Main reason to choose the passive system is budget, or because you may want to modify suspensions characteristics. Such as lowering the car, or using much heavier wheels/tyres. If the latter, it is frustrating to have the Sport differential tied to the adaptive dampers. Not just because there is some added cost (USA seems very slow to release any prices) that will be wasted, but because ripping out the CDC system and replacing it with coilovers is likely to cause problems within the chassis control system that will require some coding hacks to overcome.

Glisse

Every pre-production S4 that Audi built was fitted with S Sport adaptive suspension (plus Dynamic steering and Sport differential)... and 19" wheels.

The base configuration is fixed dampers, with 18" wheels.

Those two are more likely the "ideal" configurations as tuned by Audi, although I doubt mixing and matching is going to be a disaster.

adg44

Yes, because for photos the 19s obviously look better. The 18" wheel is the performance wheel, as we can also tell from the Sport plus package for the manual transmission A4, which is on 18s not 19s.

Sebast007

I thought the bigger the wheels, the harder/better it was for cornering, braking, etc.? It certainly all depends on the tires themselves, though. The S4 B9 comes with 19s, though I would have loved 20s (like my Porsche's ^^). You lose a little bit in comfort with big wheels, so I guess 19s should still look great and perform well enough. I'd only go for 18s on a winter wheels set.

Glisse

They will make 20" an option at some point in time (see below), but I think 19" is a good compromise, and the optimum for S Sport adaptive suspension settings. The issue is sidewall flex; the 19" combination has 13mm less sidewall. More responsive steering, less heat build up, less roll resistance. And yes, less comfort depending on the suspension setup. The 18" would be the choice if you want to trade some responsiveness for a bit more compliance and comfort, or are using the fixed suspension.

Or as you said, using as your winter wheel where it will add some protection against damaged roads.

The new S5 Sportback shown in Paris was on 20" wheels. The tyres were Continental SportContacts (and not Hankooks!!), but series 3 which is pretty old. What was interesting was that they were 265/30 R20, which suggests the new 20" rotor design is a 9" wide wheel. This is relevant because unlike the B8 platform, the S4 and S5 share offsets and have similar clearance geometry.

Many of the wheels are shared, and the unique versions are interchangeable. The A5/S5 has more 19" wheel options than the A4/S4, and all 19" wheels are fitted with 255/35 tyres, rather than 245/35 on the A4/S4.




B9 S5 Sportback with 20" wheels

adg44

The S4 Sedan and S5 Coupé do not share offsets. S5 is ET32 vs ET40 for the S4 sedan. And yes, the width of the tire is also increased on the S5 to 255 compared to 245 on the S4.

And still, as I said before, the 18" tire is the best performance option, regardless of the suspension.