If you are going for long hair and have the opportunity to do a quick fix after de-helmeting (or whatever you motorbikists say!) spraying some dry shampoo and brushing it through your hair will add back a lot of volume, and you can then do a single-elastic messy bun if you like those sort of styles. I've become a bit of a sucker for the messy bun, such a great way of keeping my hair out of the way and looking cute and careless without having to put much effort into it.. Practicing doing a nice looking bun will be key though!