Originally Posted by Billy Thunder
My Micargi is a steel framed Rover. Sister bike to the Huntington - same in every way, except a couple inches less stretch. They share the same unusually shaped top bar tube. I would bet money they are made of the same type of steel. The tubeing is quite thin and sounds hard when you tap it with a fingernail.
The motor mount I used was a muffler clamp and the large tube adapter that comes with some of the kits (drilled out to fit the large sized U-bolt of the muffler clamp). I had used a piece of heavy automotive innertube as a vibration damper, and the muffler clamp fit very well with the rubber in there.
The first thing I noticed was a small crack developing where the seat tube meets the bottom crank bracket. I had it welded. Within a week the downtube broke. I suspect the downtube was compromised before the seat tube cracked and the added vibes on the rear motor mout caused the first failure of the seat tube...
A close inspection of the failed area showed the mount had eaten through the rubber, then started on the top side of the downtube, then the rest of the break was clean, like a stress crack (no rubbed area) all the way around the tube right at the motor mount.
I have since had the downtube repaired by a professional welder, so I can't take pictures. The repair consits of welding the frame together, then a steel sleeve was wrapped around the repair and welded to the frame. I will be inspecting all areas of the frame regularly this season!
Do you know roughly how many miles you'd put on it when this happened? Or do you have a good guess? Did you have the rubber in the mount the entire time?
I'm guessing I had 1400 miles or so when I was hit by that truck. I've begun to speculate whether going with a more solid mount early on, and doing all I could to reduce vibration, may have added life to the frame. I'll never know for sure, but there are people here on the forum that seem to say the same thing, and they make a pretty good case for it.