Originally Posted by hokiefyd

Going to 584mm wheels (often called "650b" or "27.5 inch") is another good idea. In order to keep the same overall diameter as your current tires (30-622), you'd need a 49mm tire. That's not a common size, but 47mm is, which would probably be the most appropriate for your bike...if it'd fit between the chain stay tubes. You could drop down to something like a 42-584, which would almost certainly fit width-wise, but now you're reducing the overall diameter of the tire, which can change the way the bike rides (with respect to front end geometry) and will also lower your bottom bracket. Neither of these is necessarily a big deal, but just something to consider if you're thinking of changing wheels.