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The Dreaded High Speed Wobble

A Few Thoughts on “The Dreaded High-Speed Wobble”

Most of us have experienced this terrifying phenomenon at least once while descending. Today we’ll take a look at what likely causes it, what probably doesn’t cause it, how to avoid it, and how to survive it when it happens.

You’re at the top of Snow Canyon just passing the north ranger shack, and you start your descent. You go through the first two long sweepers, and your speed builds to almost 40 mph on the straightaway. And then you sense it in your front wheel. You get the sickening “uh-oh” feeling as your front wheel starts to oscillate, and the vibration builds until the wheel is deflecting an inch or more laterally, like an out-of-balance washing machine full of gym shoes on spin cycle. And once it starts, there is little chance of making it subside unless you can wrestle your bike to a complete stop, the front wheel wildly jumping and hopping. Once that gyroscopic effect starts, it does not want to stop.

Antiquated articles on this topic usually blame several pieces of equipment; bad frame alignment (something that rarely exists in the world of carbon), a bent fork (see last parenthetical statement), a tire out of round, a wheel out of true, a long fork trail, etc. All of this, other than in rare exceptions, is hogwash. Almost all the time, the cause of high-speed wobble is the RIDER. I must stress that everything further that I write on the subject of high-speed wobble is conjecture, speculation, and questionable wisdom based upon my hundreds of thousands of road miles along with my horrible descending skills. I’ve had severe wobble a dozen or more times, and I’ve managed to avoid crashing every time, except for once, and I was able to ride the ten miles home to my Bactine and Neosporin.

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Here’s a truism: It makes the most sense to avoid any wobble developing in the first place. Many articles on wobble, in my opinion, get it wrong. As potential danger seems to increase by the square of your velocity, we become frightened and we panic. High speed descents can induce The Death Grip on the handlebars in many riders, including yerz trooly. When descending, stay relaxed, smooth, and keep a light grip on the bars with your weight shifted to your feet at the 3 and 9 position on the pedals. You can easily stop mild wobble before it builds by lightening your grip and relaxing your hands and your entire body. Most wobble articles tell you to put more weight on the bars, but I suspect that is bad advice. Once the oscillations start, adding weight to the bars just exacerbates the problem. It’s a mass plus inertia thing. And when you feel the beginnings of wobble, in addition to relaxing your grip and entire body, try to reduce some speed with your rear brake. Under full-blown front wheel mayhem, using your front brake can make things worse. To reiterate, the best solution for wobble is to not let it start in the first place. Ride smooth and relaxed, without a tight grip on the bars. Keep your weight low; mostly on your pedals. I realize I’m being redundant, but this is important stuff, and you’re really not paying close enough attention.

Now, for the sake of illustration, let’s assume you have not been able to subdue the vibration and you’ve gone into uncontrollable high-speed wobble. Your immediate goal should be to mitigate any possibility of physical damage. Survival mode. As difficult as it may be, lightly steer the bike so you stay on the road. Even though it’s counterintuitive, you must relax and be smooth, despite your front Ksyrium bouncing around like a bowling ball in a cement mixer. Use your rear brake without actually squeezing the handlebar; pull the lever back firmly with your index finger; not your whole hand. Don’t apply the rear brake so hard that your rear tire skids, because you’ll lose directional stability. Stay symmetrical on the bike. In my experience, as you slow down, the wobble may violently persist, right up until you come within 1 mph of a dead stop. Sometimes physics is rude.

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No one has convinced me conclusively of an actual cause or cure for high-speed wobble, but some of my theory is based upon the fact that cold weather can induce it faster. If you happen to be chilled and you enter a descent, you may be shivering and gripping the bars too hard, and the wobble can start. In cold weather you can shiver, and your body tenses up. The cold keeps you from being fluid and relaxed. And in the same vein, if you tense up in warmer weather, your body can act as it does when you’re chilled. If you fear wobble on a descent, control your speed at the top of the hill until your confidence builds and you can relax and let ‘er rip. If you relax and actually enjoy the descent, you are far less likely to find yourself astride a 15 lb. piece of expensive, oscillating carbon fiber that’s careening, out of control, at 38 mph.

One thing I’ve noticed is if you’re descending with other riders who are going the same speed as you, the sense of frenetic speed is diminished somewhat, and you can actually go faster with confidence. It doesn’t seem as if you’re descending as fast. I’ve also found that riders who love to descend fast are never the ones who develop wobble. It’s a fun/confidence/relaxed thing. Again, high-speed front wheel wobble is almost never the bicycle, and almost always the rider. Enjoy the downhills, stay loose, and you’ll be far safer. And when you get to the bottom, wait for me. I’m three minutes back…

Written by Paul Scarpelli

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3 Responses to “The Dreaded High Speed Wobble”

  1. Dennis Wignall on 14 Jun 2017 at 11:14 am

    I have found that as the wobble commences, firmly pressing against the top tube with both knees causes the wobble to cease.

  2. huntani on 14 Jun 2017 at 11:17 am

    Nice article Paul. I have only had the wobble one time, on a new bike with adjustable rear dropouts, and the wobble was only between 40 and 45 mph. When I stopped (safely, since the wobble stopped after getting back into the 30s) I screwed the stops back to lengthen the wheelbase about 5-6 mm. I continued the descent and got back up to 45ish with no wobble. Maybe the remedy was a “cycle-somatic” effect, but at any rate the wobble was gone despite my trepidation for the next few rides on that Eddy Merckx Corsa Extra.

  3. Wayne Brown on 02 Oct 2017 at 4:42 pm

    I agree with Dennis Wignall. The few times I’ve had a violent wobble it stopped instantly when I clamped the top tube between my knees.

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