I picked up a new bike a few days ago, and was really looking forward to getting out today. This was the bike yesterday:
Note the happy, normal chain. This morning, I took off the rear wheel for transport reasons, and I somehow managed to make two loops in the chain while doing so. Nothing felt abnormal while removing the wheel, no irregular resistance at all. I've never had this happen before on other bikes (first time doing so on this), and google has been unhelpful. My chain tool is currently a few hundred miles away, and the shop is closed, so hopefully there's an easy fix for this. Here's the loop:
Take the wheel off again, fix the chain (Just play with it, you'll figure it out), then put the wheel back on ensuring that the chain stays loop free this time.
I have had the same problem.The chain sorta falls off the derailleur and gets all cockeyed.Grab the upper run of the chain,and sort of pull the lower run back thru the derailleur( or the upper run)-it probably isn't thru the derailleur like it was.You will have to "put" the chain back thru the derailleur-it probably isn't on the upper pulley like it was before.Luck,Charlie