Just wanted to start some general discussion as I have done some "research" on this and ended up still not sure of the answer Q: wonder why that bike is so rough running, perhaps worse at idle? A: Crank out of whack due to improper "brute force" installation? One forum poster said handle it like glass, tapping it in with a hammer is a no no. One poster said you would be surprised at who is doing the "no no". So sure I had to carefully tap the case around the crank to get it on. HAd a bad nights sleep when I learned it was possible to untrue a crank if you "stared" at it too long. So I conducted and experiment. I have an old crank or two lying around so I measured the distance across the web (opposite to where the connecting rod pin is), and hit the shaft with a plastic hammer several times. Web distance did not change, so I hit harder, then changed to blows on the old bearing that was installed on the shaft. These were moderate to hard hammer blows no change, so I generally beat on it moderatly for a while and still no change (0.01 mm or 0.0004 inch) I concluded that perhaps these units are not that delicate? Any comments And yes, run out with a dial indicator is more important, but I don't have one, and this was an extreme test. And of course it is very prudent to use heat and cold properly and get everything set in place as smoothly as possible, but at times this does not happen, partucularly for the unpracticed as heat and cold fitting must be done pretty fast. So how much force do you think a crank can take during installation? Thanks guys, just wanted to get some discussion going!