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"Squeezing the wheel causes wobbles." Is this really the case?


LanghamP

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Squeezing your wheel between your legs will no more cause wobbles that riding one legged will prevent them. That is, you can hold the wheel loosely or you can squeeze very hard, and everything in between, and no more encourage nor prevent wobbles from occuring.

To be clear, squeezing your wheel doesn't encourage wobbles.

Exhibit A:

Motorcycle and bicycle forks continously get more rigid. From the flexi flyers of the 28 mm Norton's of the 1950's to the now 50 mm upside downs of modern front forks, the trend, with just one exception of the foolish 1991 Honda CBR900, has always to make front forks more rigid.

Translating that to EUC terms, it means holding the wheel more rigidly should reduce the frequency of you getting wobbles.

And yet...and yet...every rider here, including me, will have experienced wobbles induced by squeezing. The manifestation of wobbles is real.

To understand what is actually happening (instead of apparently happening), we must again consult Keith Code's Twist of the Wrist, although this time book II under the subject of "rider induced oscillations".

Basically, all gyroscopically balanced vehicles are slightly out of balance. They then ever so slightly tip themselves to regain their equilibrium and hence their balance. You can demonstrate this by simply rolling any wheel or tire, and watch as it tips itself to keep balance, usually describing a circle. If you push against this natural tendency the imbalance increases, enough to turn you in a different direction if minor, or an eventual speed wobble that throws you if major (or if you foolishly keep pushing against it).

Therefore, clamping a wheel with all your strength makes no difference at all in regards to speed wobbles. If you could fashion extremely rigid cyborg legs made of metal that had no flex at all, then your wheel would be the safest wheel of all, as no wobbling caused by flexing legs would be possible.

The real reason we get oscillations when we clamp wheels is because we are stopping the wheel from naturally tipping towards its imbalance, or, worse yet, actively pushing against the wheel while it is trying to rebalance itself. 

That is, we are often rigid at the hips when we clamp the wheel, and that stops the wheel from rebalancing! If we could relax our twisting force, and just momentarily let the wheel point into the imbalance, then the wheel will not wobble. We are rigid at the hips while being loose around the legs when we should be loose at the hips while being rigid at the legs.

Think of the worst motorcycle front end; spaghetti noodles for front forks with a rusty and binding steering head. That'd be awful to ride, wouldn't it?

To be fair, all experienced riders seem to know this instinctively. That is, without exception their whole lower body looks like it's a block of concrete, with knees bending in exact unison, while everything above their body looks relaxed.

In contrast, without exception all new riders have spaghetti legs but their body above their waist is tense, often absurdly so. And they get wobbles exactly as you would expect if they didn't let the wheel steer into imbalances.

So to all riders; squeeze away! Armed with this knowledge, now you'll understand that clamping that wheel to jump that pothole at 26 mph won't put you into a wobble.

 

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I wonder if motorcycle/bicycle forks are a good corollary for our legs on a wheel, just because I feel like I wouldn't be able to ride 10 feet if I replaced my legs with rigid steel rods. :)

My thought has been that the wheel's gonna oscillate for whatever reason -- natural imbalance, surface issues, what have you -- and when you're clamped onto the wheel those oscillations translate directly to the person riding, so he/she is oscillating too; panic/imbalance ensues, followed by unplanned dismount. With unclamped legs the wheel can do all kinds of things, including oscillation, but I can generally recover because my legs aren't forced to be a 100% participant in whatever unhappy adventures the wheel is trying to impart.

That said, I only have experience with one type of wheel really, that has enough power to get up into dangerous oscillation territory, so not an expert by any means.

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