Your comment reminds me that having the right equipment-- quality equipment, equipment that you trust-- is crucial when the speeds start getting up there. Having the right frame, the right geometry, the right tires, and the right brakes make all the difference, and can turn a terrifying experience into the proverbial walk-in-the-park.

I was recently descending from the town of Montescaglioso in southern Italy on a rented bike, one that, on the ride out and up, clearly wasn't in the best nick, by which I mean the shifting wasn't crisp, nor the braking confidence inspiring. Anyway, on the way back down, even though I knew the road from the ride up and felt like I was flying back down to the point of fear, when I got back to the B&B and checked Strava, it returned a pitiful 31.5mph max! And this from an out and back ride of 23 miles that returned more than 2,500ft of gain!

Sheesh, I clock high 30mph around the little rolling hills of Ann Arbor regularly, so the low max from that trip surprised me...until I realized that it was the crummy bike. I didn't trust the tires to grip, the brakes to brake, or even that any of the bolts were sufficiently tightened to prevent a tragedy, so I was afraid and cautious.