Speed wobbles...here's what I learned.

My first happened to me ~15 years ago, on the descent from Rainy Creek Summit (Highway 66) towards Elbow Falls, in Alberta, Canada. We'd battered into a headwind to get to Forgetmenot Pond and I was determined to beat my top speed on a bike on the way back down. The two guys I was riding with held back and I gunned it. I was going pretty quickly but still thought that there was more to come when...holy $h!t!! Suddenly my front wheel/tire was just ripping at the ground and the whole bike was flexing. I wrestled the bike. I was convinced my front tire was flat because it was basically rolling off the rim on each oscillation. I knew I was going well over 85kph (>50mph) (the last time I'd looked at my speed) and the asphalt there is very coarse. If I went down on that, it was going to peel me like a cheese-grater. I think this is when my speed skiing experience came in handy; I had a moment of clarity and thought "Nigel, you're still upright so don't do anything rash". I continued to wrestle the bike and survey my options.

Ahead of me, the road gradually bent around to the right but I did not feel confident trying to steer...because I was convinced that my front tire would then entirely roll off its rim. So why didn't I just brake? Because this was my old British road bike. And in Britain, the back brake is on the left-hand side. In the mayhem, I couldn't remember which was which...and I couldn't risk pulling the front brake. So, unable (or unwilling) to follow the line of the road, I allowed myself to drift toward the other side. I could see that there was no oncoming traffic. All the while, the massive "wobble" (hardly seems to do it justice!) continued. Along the far side of the road was an Armco barrier/guard rail. I reasoned that, even if I hit the guard rail, I would flip over it and land on the loose rocks and vegetation...better than the cheese-grater.

Eventually, as my trajectory took me across the road, I did hit the guard rail, but rather than flipping over it, my handlebar hooked over the guard rail, the outside of my left calf started to get very hot because it was being friction-burned by the guard rail...and the bottom of my handlebar was hitting every post that supported the guard rail. Fortunately my fingers were "just" clear of that intercept point! Eventually, I feathered the brakes and established which was the rear...and came to a stop. My bloodstream was pretty much pure adrenaline by that time! I stepped off my bike... and made lots of strange noises and probably swore a bit. I stepped back to my bike and felt my front tire...still absolutely fully-inflated.

My friends arrived and asked "what the f-ck are you doing over there?" I made more strange noises. My only injury was a big friction burn on the outside of my left calf where it was rubbing against the guard rail. It was quite an experience! And what speed did all this start happening? Well, at some point in the proceedings, I was going 60.3miles per hour (97kph), according to both my GPS and on-bike computer.

So, in light of this event, I took it upon myself to learn about what caused it, what one should do if it happens and how to prevent it in the first place. It turns out that this is basically a harmonic vibration that becomes established...and our natural response to tighten the grip on the bike and remain planted on the saddle only feeds more energy into that oscillation. So, the advice to stop it once it starts is to slightly unweight the seat (without standing up), relax your grip on the handlebars, and press your inner thigh onto the top tube. All these are designed to dampen the vibration and allow it to "shake itself out" without feeding more energy back in. And to avoid it happening in the first place, keep a relaxed grip on the bars while descending, be prepared to unweight the seat a little. Very light braking on the rear wheel would also probably be a good move.

I actually had the opportunity to apply these methods during another high-speed wobble that started while descending on Highway 1, just outside Golden, British Columbia, a few years ago. Fortunately, the wobble dissipated quickly, which was very welcome since I was alongside some very large fast-moving semi-trucks at the time!