This would have been a lot better build (you really don't need more than 7 riding to be honest), also it's a level 30 build, not 31. Just ride around with a great lance, and you're not stranded if you get dehorsed:
Level 30
Strength: 12
Agility: 27
Hit points: 47
Converted: 8
Power Strike: 4
Athletics: 9
Riding: 9
Weapon Master: 1
One Handed: 1
Two Handed: 1
Polearm: 118