Just preload adjustment with pillion passenger is usually not enough. At least with my former GS I allways wondered, why it was considered good with pillion. We are both quite thin, but still the max preload with pillion felt not to be enough. Then once I tried to tighten the rebound damping by 1/4 turn too. What a difference! Then I understood why GS is considered good with pillion.An in "depth review" including pillion, where they couldnt be bothered to adjust the rear damping, so the bike gets slagged for a harsh ride two up, pitiful.