Originally Posted by adamrice

If you're riding the bike pictured as your avatar, you're noggin isn't that much closer to the ground than it would be on a diamond-frame bike, so I'd say that if you consider them needed on DF bikes, you need one too.

The question isn't so much whether you're at a lower risk for a specific type of accident, it's the number of Gs your brain will pull when it hits the ground. Your lower center of gravity will not protect you if you're hit by a car, and IMO endos are mostly an issue for mountain-bikers. It's possible to endo on the road (on a DF bike) but I've never met anyone who has actually done it.