Motorcycle Ergonomics, Part Two
By David Tong
In my first article, I suggested the details of what riding position and control placement can have for static comfort on a motorcycle. Now, we will go into the details of how this actually works in the real world.
First, I would like to address the riding position on a motorcycle without any kind of windshield or fairing. I submit that a slightly forward-inclined torso, perhaps 5-10 degrees from vertical, with one's knees also bent about 5-10 degrees from vertical, heels placed roughly below the forward third of one's thighs, is a nearly ideal position for riding into a speed-generated headwind. Depending on body type and size, this position is generally attained with standard bend, moderate height and width handlebars without a lot of pull back and mid-position foot pegs (neither forward nor rear-set).
By having one's heels behind the knee, the feet are in a good position to help the rider rise from the saddle by simply pushing downward on the pegs, without resorting to strong pulling or pushing on the handlebar. This is desirable on long distance rides when you simply wish to stretch briefly, or when you are approaching a speed bump, uneven crossing or large pothole ahead and wish to transfer weight from your butt (on the seat) to your bent legs (on the pegs) to help absorb the shock. This makes the ride more comfortable. (Off road motorcycle riders do this all the time.)
It also generally takes a lot of pressure off your pelvic bones and adjacent tissue, by allowing your inner thighs to take up more of the load. This helps to extend the length of time you can ride before fatigue sets in Typically, I go no fewer than 200 miles before having to get off a bike for a breather. I like to ride, not stop.
Generally speaking, mid-set pegs are typically found on standard (roadster) and sport touring type motorcycles. Foot pegs placed directly beneath or forward of the rider's knees are fitted to bikes that are usually ridden conservatively. Typically, this would be bikes of the cruiser or heavy touring types. Rear-set foot pegs are typical of sport bikes and cafe racers.
More important is the slight forward lean of your upper chest. The classic British roadster, as typified by the new Triumph Bonneville and classic BSA Lightning A65, Norton Commando 750/850 and Triumph T120R Bonneville, all had rather wide, but fairly low, handlebars and mid-set foot pegs to aid rider comfort by allowing the rider to brace against the wind force. This also means that direct, forceful action can be transmitted to the handlebars for superior control on twisty roads, for low speed maneuvering (as in parking lots), or in emergency situations. (Interestingly, this same riding position also works well on motorcycles equipped with a simple windshield or a quick detachable sport-shield. -Editor.)
I think it was the Germans, mostly BMW, who first supplied motorcycles from the factory with short and relatively narrow handlebars. Without a windshield, placing the rider slightly over the gas tank means a weight transfer forward, more over the front wheel, enhancing stability at high speed. It also means that the rider is not hanging on for dear life as he or she would be if bolt-upright, although sacrificing a measure of low speed maneuverability and control.
Mind you, I am not advocating the use of so-called Clubman or clip-on sport bike handlebars. These place the rider into a racers crouch, superior for reducing air drag at high speed, but put way too much pressure on the wrists, shoulders and neck for comfortable street riding and touring. Such handlebars also restrict the rider's range of motion and impede emergency and low speed maneuverability. Visibility in traffic is relatively poor when crouched over the gas tank.
For a faired motorcycle, while I prefer the same leg placement described above, one has more latitude about torso lean. While one can still steer a bike in a superior fashion by leaning forward slightly, one doesn't have to hang on against wind-pressure with a frame-mounted touring or sport touring fairing.
I emphasize frame-mounted, not a fairing affixed to the handlebar or forks, because the latter can adversely influence steering, especially when riding into a crosswind. They can also cause stability problems at higher speeds, because the vast majority of them are placed at roughly the same angle as the forks, more a windbreak for the rider than an aerodynamic enhancement to smoothly move air around him. The wind pressure can feed artificial steering inputs to the bike, especially in the case of motorcycles with a short wheelbase and more steeply raked forks.
I particularly noticed these wind generated steering inputs while riding my 1996 Triumph Thunderbird along Pacific Coast Highway in southern and central California. The winds along the Pacific Ocean change a lot and when moving at speed, over 60 MPH, the fork-mounted factory accessory fairing made the bike dance around more than I liked.
In contrast, the wind-tunnel tested BMW R1100RS and R1100RT motorcycles I owned were serenely calm in the same conditions. Not only were the fairings designed to efficiently cut through the slipstream, they also moved air around the rider, not merely shoving it aside. This results in a quieter ride, with far less helmet buffeting and backdraft hitting the shoulders and upper back. (See Sport-Touring Defined: The BMW RS Series for more about BMW sport touring motorcycles.)
Sport touring and other performance oriented motorcycles generally require a somewhat taller suspension for increased ground clearance and lean angle. This typically results in a higher seat.
I have found a higher seat to be a good thing when it comes to viewing above and around traffic and to see down the road at higher speeds. Then again, I have a 32 inch inseam and need the space to be comfortable. Others do not and a tall seat admittedly raises the center of gravity and makes maneuvering at typical city speeds, in stop and go traffic, or in parking lots more difficult.
I know Motorcycle and Riding Online Editor/Owner Chuck Hawks prefers the lower seat height (around 28-29 inches with touring seat) of his trusty H-D Super Glide Sport to most modern sport touring bikes, especially for passenger comfort and for suburban commuting. I do not disagree with him about this. At the same time, I am used to over 30 inch seat heights and prefer the higher eye level perspective for safety reasons, so there are certainly two cogent views to consider here.
Either way you slice it, it is entirely possible to spend a long day on the road without becoming an aching basket case at days end. Be honest with yourself, your desire for weather and wind protection, the anticipated average velocity of your journey, the typical road conditions you expect to encounter and choose accordingly.
Copyright 2015 by David Tong and/or chuckhawks.com. All rights reserved.