Motorcycle Ergonomics By David Tong This article will discuss how ergonomics play a vital part in riding comfort. This is especially relevant to the touring or long distance rider. First, the basics. When a rider sits on a motorcycle, the reach to the handlebars should neither be too short nor too far. The reach to the handgrips is highly dependent on the seating position of the particular bike. Sport bikes, cafe racers and racer replicas with clip-on or Clubman type handlebars often require riders to stretch to reach the handlebars. One should not feel cramped, with elbows severely bent, or struggling to reach the handgrips. This may be a function of the size or length of the gas tank, the length of the engine, or the amount of pull-back of the handlebar. It is best to have handlebars that place one's hands below shoulder height, but above the knees for best comfort and control at normal speeds. The handlebar should allow one's wrists to fall at a natural angle to afford a straight wrist angle for maximum steering leverage, as well as a secure and fatigue-free hold for long hours on the road. Extreme handlebar types (ape hangers, clip-ons, etc.) can be quite uncomfortable. Conventional, tubular steel handlebars can be rotated up or down, or bent, to change hand position. They are easily replaced if they do not fit the rider. Note that most imported motorcycles come with a 7/8 inch diameter handlebar, while Harley-Davidson's and most domestic motorcycles come with a beefier, one inch handlebar. The handlebar and the seating position largely determine the relative angle of one's torso while riding. Cruisers and standards usually put one nearly vertical to the wind. This may feel good at rest and offers good control and visibility for typical urban/suburban riding. It can also work at freeway speeds, if the motorcycle is equipped with a good windshield or fairing. However, if one adds high speed wind blast to the equation on a naked bike, it is my view that a slightly forward leaning position makes the rider feel more secure at speed. It may also be easier on the rider's back, a matter of personal opinion. More about wind protection later. The handgrips should provide a secure hold. Usually, the stock grips that come with the bike are satisfactory. Most standard grips are cylindrical in shape with some kind of texture or patterning to improve friction and grasping pressure. The synthetic rubber used these days is durable and UV resistant, with a bit of give. I see no reason to swap grips unless you find the stock grips uncomfortable. However, some riders prefer softer accessory grips. A larger diameter grip along with a one inch diameter handlebar may help if you have large hands. Some riders prefer barrel shaped grips that fill the palms. Often these grips have some kind of air-pocket inner construction that offers some vibration reduction. This can be handy if the bike is plagued by vibration, or if road conditions are poor. I have become spoiled by electrically heated grips for winter riding. They are a godsend in cold weather. Cold, numb hands are not a good recipe for maintaining control, especially if it is raining. Most clutch and brake levers are secured to the handlebars by screws or bolts. These can be loosened and the levers rotated to afford the rider's fingers a straight-line draping over the tops of the levers. This is important. It reduces hand strain and fatigue more than almost any other adjustment on a motorcycle. It can help prevent sore wrists and fingers from lots of clutching and braking. Seats are a highly individual matter. Their design is nearly always dictated by the style of the bike and only secondarily by comfort, which seems backwards to me. Many stock seats are not very comfortable. Accessory seats are available for most motorcycles and the stock seat is the first thing many experienced riders replace. "One size fits all" simply doesn't work for many riders or for most passengers. Seat height is typically governed by the type of bike. Cruisers nearly always have the lowest seat height. Standards and tourers usually occupy the middle ground, while sport bikes have the highest seating arrangements. A tall seat raises the center of gravity of the bike and rider, never a good thing, and makes it more difficult to reach the ground when stopped. Passengers, especially, will find it more difficult to clamber onto a tall seat. Seats should be wider under the rider's butt and narrower toward the front, to allow the knees to be tucked close to the gas tank. A narrow seat front also makes it easier to get your feet firmly on the ground when stopped or when paddling around a parking lot. Dual-density, molded foam seat construction allows some give on top with firmer supporting foam below, making the seat more comfortable, as well as durable. Choppers and custom show bikes usually come with skimpy, uncomfortable seats and handlebars that result in a very uncomfortable riding position and compromise controllability. They are obviously intended to be ridden very little. Some sport bike seats are nearly as uncomfortable as chopper seats, while others are relatively acceptable. Mainstream cruisers usually have some sort of deep dish bucket seat, which can be good in terms of support and padding for one's sit-bones, although it allows only one riding position. The usual cruiser riding position is upright with all of the rider's weight is concentrated on the seat. There will be none of the mitigation that a slightly leaned-forward riding position creates by shifting some of the rider's weight to the inner thighs and handlebars. This riding position increases the likelihood of numb-butt after hours in the saddle. Standard motorcycles usually have flatter seats, sometimes with a slightly raised passenger pillion, that allow for more fore and aft rider movement on a long ride. This can also help increase the number of hours or miles one can comfortably ride, provided the seat has a flat, not convex, shape. The most comfortable motorcycles are luxury touring bikes. Touring riders spend a lot of time in the saddle and they know what works. The manufacturers of big tourers truly do pay more attention to ergonomics in the design of these bikes and their seating arrangements. My 1988 Honda Gold Wing GL-1500/6 and 1996 BMW R1100RT were supremely comfortable over long distances. I suspect that a Harley Ultra Electra-Glide, BMW K1600LT, or Victory Vision Tour would be similarly endowed. Their seats are tapered toward the front, while wider and softer under your fanny, the best of all worlds. I have had seats custom made and my preference is for a dense gel top pad over a standard, closed cell foam base pad, with a leather seat cover for the actual seating surface. Leather is more fragile and requires moisturized nourishing and cleaning, but it breathes and is nearly always more supple and cooler than vinyl. However, marine-grade vinyl can also suffice and saves money and maintenance effort. The absolute worst seats I have ever ridden on were the stock seats on the original Harley V-Rod and the Ducati 998 Superbike. Both were hard, unyielding and too narrow. They very much limited how long I could ride on them without wanting off; maybe 100 miles at most. Style often dictates foot peg location, particularly for sport bikes and cruisers. Cruisers will nearly always have some kind of feet forward riding position, which places more weight on one's butt and decreases cornering clearance and rider control. However, it does allow a more open knee bend, which some riders find comfortable. I suspect riders with long inseams will understand this. I remember riding a Harley-Davidson Sportster Sport and a Custom Sportster years ago in a road test comparison. Due to the low seat on both, the Sport's foot pegs bent my knees too acutely. This positioned them higher than my hips, which when coupled with the relatively low standard handlebar put pressure on my pelvic joint. The Custom, on the other hand, opened up the rider triangle. This is defined by measurements that take into account reach to the handlebar, seat height and foot location. I found the Custom incomparably more comfortable than the Sport, mainly because of the latter's relatively high foot peg location. The Custom also had forward pegs that were comfortably close, neither requiring locked and extended knees and shins, nor being too close and requiring excess knee bend. Foot pegs on the Beemer RT were a bit farther back and higher, as befitting a sport tourer designed to allow more cornering clearance. However, they still allowed me to easily stand right up to stretch while riding and were not in the way while pulling to a stop or parking. The Honda's perch, on the other hand, was about as comfortable as riding in a car seat. Even better than some. Sport bikes will nearly always be uncomfortable to all but the very young and caffeine-addled. Their riding position puts too much weight on the wrists and hands. It makes sense for a race bike, because it locks you into one spot, desirable for very high speed control precision. In my earlier riding days, I rode a number of sport bikes, including a 1992 Honda CBR-900RR, 1995 Ducati Monster M900, 1996 Kawasaki ZX-11D, 2000 Yamaha R1, 2002 BMW R1100S and 2003 MV Agusta F4S 750. Each was exhilarating to ride in short spurts, but only the ZX-1, R1 and the BMW S were tenable for any distance beyond 200 miles in a day. Splitting the difference between the upright standard or cruiser riding position and the racing crouch of the sport bike is the sport tourer. Pegs are lower and farther forward than on a sport bike, so that the extreme knee bend preferred for cornering clearance at high lean angles is substantially reduced. Their thick rubber covers absorb vibration. The seating position is intended for all day riding comfort by allowing one's inner thighs to support some of the weight on the seat, as mentioned earlier. This is good for long days on the road. On two BMWs, I rode between 700 and 1150 miles in a single day, without being unnecessarily thrashed. Finally, a word about wind protection. When I first started riding, motorcycle manufacturers rarely fitted aerodynamic fairings to new bikes. Usually, what constituted wind and weather protection was a nearly bolt-upright Plexiglas windscreen. These were good for taking wind pressure off one's chest and wrists, but they usually caused lots of backdraft due to the swirling air currents (burble) over the top of the shield. They are also, generally speaking, not as quiet as one might think and can cause a lot of helmet buffeting. Because the wind load on the windshield is transmitted into the steering head, high speed or a strong cross wind can affect steering. The better designed windshields are mounted to the front forks, not the handlebars. Some are quick-detachable, offering maximum versatility. Wind and weather protection for the head and torso can be surprisingly good, although the arms and legs are exposed. Careful adjustment is required when installing a windshield to minimize the negative effects mentioned above. The lowest windshield that provides the desired protection is best. Today, motorcycle manufacturers often fit a wind-tunnel tested fairing to sport touring and touring models. These reduce air drag at high speeds. Most fairings are firmly attached to the frame of the motorcycle. This means that changing wind directions do not adversely affect stability or steering and OEM fairings usually make for a quieter ride. Frame mounted touring fairings provide the ultimate in protection for both rider and passenger, including to the arms and legs. Handlebar/fork mounted fairings put all of their weight, which can be considerable, on the front suspension. They affect the motorcycle's steering, especially at high speeds and in cross winds. Protection to the upper body and hands is usually good. Some installations include lowers to protect the rider's legs. Some riders prefer to look just over the top of the windshield in their normal riding position. This means a lower windshield, which is good. Others prefer to look through a tall windshield. Either way, a good windshield, whether a stand alone model or part of a fairing, should deflect the wind stream above the rider's face (at or over the top of the helmet). A poorly designed windshield that directs the slipstream into the rider's face is usually worse than no windshield at all. Sport bikes often come with full factory fairings and low, curved windshields. They are designed for a sporty appearance and to reduce air drag when the rider is in a racing crouch. There is very little benefit in rider comfort. I hope this short article will get you thinking. It is the product of nearly 400,000 miles on the road over a quarter-century. Enjoy your ride! |
Copyright 2015 by David Tong and/or chuckhawks.com. All rights reserved.
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