I have a '08 GL1800 and have just returned from a two-up fully loaded trip during which the ride seemed awfully soft even with preload set to 17. In the past I have ridden solo at 6, solo and packed at 10, and two-up loaded at 17 but the softness was noticeable this trip. I have since ridden it with preload set at 17 and at 6 and don't notice any difference. Is the preload function something that is known to fail? Is there a way to determine whether it is working? The bike mileage is just over 53,000 if that has an relevance.