[carl_d]

Originally Posted by HighlandPete

I've test driven two F10s 'back to back' and have to say the Autocar comments, so far, are making some sense. The standard car on 18" wheels is flawed. Based on the first test drive I wouldn't be ordering an F11 touring, as the run-flat tyres have too much influence on the steering and vibration back to the steering wheel, broken surfaces make the car fight for line and spoil the composure. Some weird sensations come back through the car on some surfaces. Cause a numbness and vague feel to the steering.

The second car had Dynamic Drive and was on 19" wheels, the car was much more composed even on the normal setting, steering more meaty and when switched to sport, the car was even more composed and settled. On poor or broken surfaces and twisty roads, the car was so much better than the standard car. No strange feedback or vagueness in the steering, even on normal setting.

The next test car will have the whole Adaptive Drive package, as I need the car to drive with more poise on poor road surfaces, but sporty when on some decent roads. So very interested to see how VDC works with the active roll bars.

To me, the run-flat shod wheels are still the issue here, and I'm to be convinced which size will work better on these cars, 18" don't work, IMO, the frequencies they generate, feed back in conflict with the suspension. Same as in the 3-series cars.

I'm surprised the 19" wheels work better than 18". The dealer has tried 20" wheels and they completely spoil the ride, I'm informed.


HighlandPete

Pete, thank you for this. I get these issues in my E90 M-Sport but I have to say it's often because the tyre pressures are slightly low! RFT's do not like being under inflated even a tiny amount. May be worth a check? I've been running with 0.1 BAR above spec to no ill effect with improvements

Back to F10, seems the standard suspension is best suited to non-RFT on 17" wheels? I understand all 17" wheels have non-RFTs?

BTW, VDC has been tuned for 18" RFT's and other wheel/tyres combinations will be a compromise!

What I find interesting is that the M-Sport suspension (listed on bmw.de but not on the bmw.co.uk configurator) cannot be selected with any trick chassis option. The M-Sport set-up will likely also be tuned for 18" RFT wheels - this I hope will be the better sporting option for the UK without going to the extra cost of the extra chassis tricks. Wish BMW UK would stop messing around and release all the options so we can find the best one.