I recently built a pusher trailer because I didn't want to #1 hack up my bicycle #2 have a motor mounted on my bike when I ride off-road #3 it is all easily detached in less than a minute from my bike and #4 little to no bike modification. I have learned a lot (through failure) but have built a really good and reliable pusher that gets 50+ mpg and will go up to 30mph depending on the set-up I use. I now have over 2000 miles on it with many more in it's future.