I would never trust the handle and wheels on stairs. You'll rip up the back of the bag as well. It's so light - just use the handle on the side, and roll it when you get to a flat place. The #9 case is way too big for me - KB flops around, and it's got oo much bulk to it. I like the snug fit(#7) - just take your time with the zippers, that's all. Pull the case all around the KB before you start to zip.