I have SOOO much more confidence on my mtb than my road bike on descents. I find that i completely panic on the road, and i can fly down the gravel paths on my mtb (with my husband yelling at me to slow down...hahaha). i have been trying to work on my confidence, but after reading these posts, i am thinking my feelings of instability are more related to bike handling? i just feel like i am going to fly over the handlebars on my road bike, not matter how low or back my weight is (and i too, descent like a mtb-er)