Originally Posted by Skyseternalangel
Well it takes a lot of rider balance and self balance for the horse to go truly straight.
Do you canter her off the rail in the arena or stay on the rail? She was probably using that as a crutch, so now you discover her canter needs some work.
I would find a big open field and canter in straight lines. Also watch that you aren't cueing her with your collapsed hip or leg slightly tighter than the other.
Has anyone else ridden her at the canter.. is it the same?
I usually stay on the rail, and I also ride with quite a bit of balance too. She does this in the field, thought only sometimes. It is the same when other people ride her. But thank you for the advice, I'll be more conscious about what I'm doing next time I'm riding her and do some drills : )