I would definitely try a lighter tire. Even the original version of the KH26 didn’t fit a 3" tire because Kris thought the volume wasn’t necessary for the wheel size. Look at the “official MUni tire review thread” for ideas. It sounds like a Maxxis Minion 2.7 is a good all around tire, and the Continental Rubber Queen 2.4 gets at least one good review. The reviewer said that it pushes the limit of what the original KH26 frame could handle, and so I’m pretty sure it’s a fat 2.4.