I ride 26" I have found its all the young riders or people who havnt been into trials for long are the types that go for 20" Now this is ok if your small, but I feel most are riding 20" because they find it easier, I think thats a bad thing to do....you kinda get skill handed to you on a plate with 20". a 26" takes a little more work, but it really teaches you vital skills, its worth it in the end. Another reason I think 26" is better is that you get MUCH more satisfaction out of it. Say you sidehop 45" on a mod and then do it on a stock, you will feel better for doing on the stock because its harder....thats just how I feel anyway. Also, 26" is more suitable for other types of riding, dh, jumping, bmx etc, get most bang for your buck with stock