In my interaction with motorcycle riders across the country, I have found that many think that weaves, wobbles, or high-sides only happen to sport bikes at very high speeds, but nothing is farther from the reality.
Front-end wobble, or as it’s sometimes called “low-speed wobble,mostly occurs at speeds of 40 to 45 mph with a side-to-side oscillation of eight to ten cycles per second. Wobbles also can self-initiate at higher speeds, and might become so violent that the handlebars will contact the fuel tank; that is where the term “tank slappercomes from.
I have seen riders at Harley-Davidson testing Road Glides take the handlebars at speed and purposely put the front end into a high-speed wobble by whipping the bars in a single direction after which removing their hands to demonstrate the positive dynamic stability (the front-end wanting to return to center) of the machine. I’ve always said that motorcycle test riders are a special breed, or simply plain crazy.
A wobble is often induced by a rut, pothole, or another irregularity in the pavement, and the shortcoming of the suspension to react fast enough. Because of the effects of positive dynamic stability, as mentioned earlier, the motorcycle will tend to correct itself, but too often the rider will over-correct and put excessive input into the handlebars, causing the situation to amplify. In the event you encounter induced wobble, the best plan of action is minimal handlebar input by the rider and permit the motorcycle to decelerate.
High-speed weave usually occurs at speeds in excess of 70 mph, and the motorcycle will follow a sinuous path of three to 5 cycles per second in the beginning, and might increase at such a dramatic pace that the rider will quickly lose control of the motorcycle. One in every of the commonest causes of high-speed weave on touring motorcycles is the uneven and over-loading of the saddlebags.
Combine this with an owner who has neglected maintenance of his motorcycle-items like low tire pressure and worn wheel or neck bearings can be a recipe for disaster-and this will actually cause a high-side. The one real way out of a high-speed weave is to detect the instability early and decelerate. I have personally accelerated through a high-speed weave and the motorcycle did
straighten out, but the weave returned as I decelerated. Not fun stuff!
Most riders don’t recognize the dreaded high-side as a wobble, but it is. A high-side is basically a wobble that becomes catastrophic in only one cycle. A high-side crash typically happens in a corner when the rear wheel of the motorcycle spins out, causing the bike to slide. The actual high-siding occurs when the rear tire regains traction with the road, flinging the rider off the
bike with great force, usually over the handlebars.
Most high-sides are brought on by the improper use of the rear brake while cornering at a high speed or sudden lack of friction between the tire and the surface caused by sand, oil, or another debris. As the rear slides out it may quickly find grip, after which begins rolling in a direction other than the one the motorcycling is traveling sending the rider over the bars as the motorcycle begins to right itself.
MotoGP World Champion Valentino Rossi sustained a compound shin fracture from a nasty high-side crash in 2010. One of the best solution to avoid a high-side is to ride within your limits on a properly maintained motorcycle. ABS brakes and traction control are quickly becoming more common and can assist in preventing high-sides because we just can’t react as fast as a computer can. Although as in Rossi’s case, no technology is fool-proof.
There are many causes of weaves and wobbles-most are maintenance related and will have been avoided. Items like loose wheel bearings, improperly adjusted or worn neck bearings, loose axles, pivot shafts, neglected tires, worn shocks, leaking front forks, missing fork braces or stabilizers, and engine mounts can all cause a catastrophic accident. A rider should have his or her own pre-ride checklist and use it before each day’s ride begins. It might just save your life.