This sounds like a stupid question, but did you trim the fat end or the tapered end? I cut about 1 1/2" off my tapered end and it still won't go under my tire because my new tapered end is too thick. So now I'm going to have to sand it down or cut it even shorter. I even cut the 45 degree corner off the thick end as Old Coot had suggested.
2013 Roo 183
2012: 1042 Miles, 13 Nights camped
2013: 2772 Miles, 27 Nights camped
2014: 2259 Miles, 30 Nights camped
2015: 1644 Miles, 20 Nights camped
2016: 550 Miles, 11 Nights camped