Nothing beats a full day of riding on a motor bike. The feeling of complete freedom. The sights and smells of the open road. Sometimes, the day is perfect except for a single problem, soreness and cramping of the thenar muscles at the base of the thumb. For some, the anticipation of hand cramps or hand pain can force the rider to set a concious time limit to a ride. Others may find that hand injury or disease (such as arthritis or repetitive strain injury) interferes with throttle control. Techniques and tools for the riders who can not ride without assistance add comfort and convenience for riders who do not require it.
All motorbikes, scooters, motorcycles, and mopeds, utilize a spring return twist grip to control the throttle. Rotate the grip counterclockwise or back towards the rider allowing more gasoline to flow to the carburetor or fuel injectors, and the motor speeds up. Release the grip, and the throttle rotates back by itself slowing the bike by reducing the flow of gasoline. To maintain speed, the rider must grip the throttle and hold it in position. The constant gripping force tires the muscles of the hand, especially the thenar muscles of the thumb. Work past the pain, or mask the pain with medication, and repetitive strain injury can result.
There are a few strategies to reduce the stress on the hand. One popular technique is to take frequent breaks to relax those sore muscles. This is a good idea anyway. Stop for gas, stretch, have a soft drink, and rest a bit. Fatigue is a common cause of accidents. Unfortunately, the hand strain continues during the ride.
Another way to reduce hand strain is to use a motorcycle cruise control. These are devices that cost about $500.00 plus installation. They appear to work the same as any automobile cruise control maintaining a chosen speed by actively adjusting the engine directly. Only the most technically adept riders will install these devices on their own bikes, so count on hiring an experienced mechanic for this job. Cruise control devices are bike specific. Here are links for two aftermarket devices for high end motorbikes: http://www.cruisemount.com/index.htm cruise control for Harley, and http://piratesk12site.net/Cruise.htm cruise control for BMW.
Throttle locks attach to the throttle, and when active, apply enough friction to the throttle grip to prevent the throttle from returning to the neutral position when released. Activate and deactive this mechanical device with a lever or push button. One brand of throttle lock, www.brakeawayproducts.com, also releases with the application of the brake. A correctly adjusted throttle lock will allow smooth, intentional movement of the throttle when active. Throttle locks cost from about $30.00 to over $100.00, and are relatively easy to install. Other throttle locks are available from http://www.rattlebars.com/mtz/invisible.html, http://www.madcorider.com/motorcycle-cruise-control.html, and http://www.madcorider.com/motorcycle-cruise-control.html. Please note that while some manufacturers refer to their throttle locks as a “motorcycle cruise control”, they do not operate to maintain a set speed on varying terrain as a true cruise control does.
A very simple and inexpensive stress relieving device is a plastic throttle lever such as a Throttle Rocker (http://www.throttlerocker.com) or a Cramp Buster (www.crampbuster.com). These plasic levers have one end that curves around and grips the throttle grip. The other end is flat and straight or gently curved. The author uses a Cramp Buster on his Honda Reflex scooter with excellent results. The lever clips firmly onto the throttle grip. It is easy to adjust by pushing the lever backwards around the grip. Adjust the lever so that when the throttle hand rests at a neutral position the bike is running at approximately the chosen speed. Adjust the speed by resting the hand more or less heavily on the lever. One problem is that the lever may be in the way when braking to a stop, continuing pressure on the accelerator. Another problem, is that adjusting the lever to the correct position at highway speeds is difficult, but becomes easier with practice. The Throttle Rocker and the Cramp Buster cost less than $15.00 each.
Riders should take care to prevent injury to their hands and wrists. Using stress relief tools and techniques might allow some riders to ride longer distance, time and years.
