I wouldn't wear these while riding, I could easily see them falling off if you bail. Also there's no volume control so you'll have to park them around your neck or dig out your ipod if you need to hear something other than your tunes.
Other than that though I've been pretty impressed with the lowriders - decent sound quality for the price, and I love that they collapse and fold up for storage in a backpack or pocket. They're pretty comfy to wear but after a couple of hours straight they start to hurt my ears a little because they sit right on the ear, but that's to be expected of any headphone that's not "over the ear" style.
Overall, pretty sweet 'phones.