Driveshaft failure on a BMW R1100RT

Riding to the Blitz to Branson one year, just outside St. Louis, my R1100RT bumped a few times like I was going over a rough road. I looked down to see what it was and realized the bike was starting to coast. I got to the shoulder and found that the motor was running, but nothing happened when I let out the clutch. So off to the local dealer on a tow truck.

First phone call from the dealer: “There’s a hole in your swingarm. Yes, a hole.”

Second phone call: “We had to cut the swingarm off with a Sawz-All.”

Third phone call: “We have the swingarm off and found the output shaft on the transmission is bent”.

Fourth phone call: “As long as we have the transmission off, do you want us to put a new clutch in?”

Eventually I flew down to St. Louis and picked up the bike and a box full of broken parts, and left $3500 lighter.

The bumping I had felt was the front u-joint on the driveshaft letting go, and the driveshaft flailing around and breaking things. At least the rear wheel didn’t lock up.Other than a vague feeling of a vibration when bouncing through a dip in the road that I had noticed about 50 miles before, there was no warning.


The broken driveshaft


Closeup of the broken u-joint


Closeup of the u-joint


Smashed broken end of the u-joint


Hole in the swingarm


Hole in the swingarm. You can see inside where the driveshaft was flailing around


Nice crack through the swingarm and the sawed-off pivot pin


Another view of the swingarm


You can see where the driveshaft was beating on the inside of the swingarm


Clutch splines were in good shape


These splines look good too