I recently installed some angled valve stems on my sport bike, to make it easier to air up the tires. The stem on my front wheel catastrophically failed while at highway speed, and I almost crashed. One moment I had a tire full of air, and the next I was fighting to keep the bike upright, while having impatient car drivers swerving around me.

My advice would be to avoid using these sorts of items on a sport bike, as the centripetal force placed upon the angled stem is more extreme on a sport tire than on a cruiser style bike.