I have a Shoei MX helmet that I've used with my dirt bike. Just got a dual sport and am going to use it on and off road (city, highway, dirt). Should I get a street helmet for my road only trips (e.g. Arai signet--best head fit)? Should I get a dual sport helmet (less good on the road but better at both?)? Should I get both? Both is expensive but I'll do it if it's the best idea.