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Originally Posted by Tjalle
cSurf: I don`t buy that:
-run flats could be a comfort issue - not performance.
-EPS is programmable - if the 20" and DDC does not solve the problem, I will challenge BMW.
Are you saying, that you also have that problem - whatever model you are driving?
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EPS was borne out of compromise- hydraulic systems are heavier and create more parasitic drag (reducing MPG) compared to EPS. Reducing weight and drag are the best ways to improve mileage (and meet CAFE requirements), but they're also the most expensive when balanced against safety regulations and customer desire for high level so in-car technology.
To your challenge, EPS software is constrained by the sophistication of the corresponding hardware. Improved response, feedback and on-center feel will require evolutionary hardware (sensors, etc.)- there's no panacea via upgraded algorithm (or, I would guess, any institutional desire to spend resources making marginal improvements to the existing software). For context, M GmbH just deployed BMW's best EPS system in the F80/2 and M GmbH actively advertises the fact that it shares none of its software and little of its hardware with the rest of the series (F25 included). I have no doubt that the EPS systems deployed on future volume models will improve, I just wouldn't hold your breath any seeing any marginal improvements for this one (particularly given the short life cycle of the F25/6). If I had to guess, the next gen X3 will share hardware with the LCI 3 series, which may borrow some of its tech from the F80/2.
Run flats- like EPS- are an exercise in weight reduction aimed at helping BMW meet emissions targets. Spare wheel/tires were low hanging fruit in the quest to lower weight (as it was being added elsewhere in the car). Again RFTs- despite perceived advantages- are a compromise (for those who are performance-minded). Dampening response (aka comfort) and the transmission of cornering forces (aka steering feel) are worse than they would be otherwise be if the car were designed with normal tires. The sub-optimal steering response of RFT is one of the reasons why M cars still come with non-RFT, while also forgoing a spare (for the BMW mobility kit).
Again, EPS and RFT are (at the moment) a necessary compromise to meet CAFFE requirements- not improvements to vehicle dynamics. If you want an uncompromised experience, you'll need to spend a bit more (or wait a few years for better tech). Having unreasonable expectations of the steering feel on entry-level SAV with first-generation EPS and RFT is almost certain to leave you disappointed.