[twindman]

I always thought 'bucking' was bouncing up and down due to weak springs, etc. But I just went from a 2006 Silverado to a 2012 Silverado. It sits 1-1 1/2 inches higher and the bed rails are another 2 inches higher. So I installed a 'riser' (?) on my hitch to get the trailer overhang back up to 6-7 inches over the truck bed. But now the trailer is about 5 inches higher than on the old truck.
Anyway, I never had a bucking problem with the 2006 in over 60,000 miles of towing. This summer I have had what I assume to be bucking, occur twice when I was braking fairly hard. Could it be because the trailer is much higher?
Any advice will be appreciated.
Thanks.