My crank keeps falling off my bike?

[t C]

Hi, I have a norco six 2 2007 and the crank continues to fall off on it every couple days of riding. I replaced the complete bottom part where the crank arms attach to the frame and the crank arms as well, and guess what happens today. IT FALLS OFF!!!!!!!! if you've had this problem or know how to help, it would be appreciated, thanks!

 

[Bob A]

You want to put grease on the threads of the bolt so that it can be torqued correctly.

 

[John]

My friend had this problem, but his dad tighted the bolt with a wrench and it didn't happen again.