Bicycle Seats Explained

July 1st, 2009

By Jim Langley

Pity the poor bicycle seat. Few products in the history of sports have taken such a bum rap. Prostate problems. Numbness. Boils. Infections. Chafing. Even impotency! You name the malady and it’s likely been blamed on the pedaler’s perch, the bike saddle.

Some criticism is justified because any reasonable person might assume that if you buy a good bike, you get a good seat. In fact, you might not even give the seat a second thought and start logging big miles immediately. And, if you develop pain and discomfort, you might cling to the notion that it can’t be the seat and simply keep riding, figuring that if you pedal enough, the aches and pains will disappear. If you’re lucky, that might happen. But, it could also be a bad mistake — the type of oversight that could cause many of the problems mentioned above.

Unfortunately, bike seats are not that simple. A seat is a bit like a pair of shoes. The same way you’d buy a certain sneaker for a particular foot and sport, you must purchase a saddle that fits your body and your style of riding. What’s more, and this is absolutely crucial for problem-free cycling, the seat must be expertly adjusted to fit your body (see sidebar below). Often, a perfectly adequate seat will feel awful and cause trouble simply because it’s not set correctly.

The Science of Bicycle Seats

Your seat must fit your type of riding and your body. The faster you ride, the more likely it is you’ll want a narrow, racing-style seat. This is because, a fast-riding position on a bike shifts you forward placing more weight on the hands and feet and reducing a lot of the weight on the seat. Also, as you pedal more vigorously, you spin faster and you can’t tolerate interference from the sides of the seat.

As you ride more casually, however, such as on a cruiser bike with wide backswept handlebars, most of your weight is planted directly on the seat. Plus you don’t pedal quickly at all. These factors make a wide, heavily padded saddle ideal to support your weight and provide cushioning.

Equally important, most manufacturers offer their popular seat models in both men’s and women’s versions and there are significant differences.

Because male and female pelvises differ (women’s are wider), it’s usually (though not always: women sometimes do fine on men’s seats) a good idea for men to start with men’s saddle models and women with women’s. The former is a bit longer and narrower while the latter is a bit shorter and wider.

Next, the seat must fit your particular anatomy. You can sometimes see how you fit a seat if you sit on it for a while then get off and immediately look closely at the back of the seat top. If a saddle is right for your body, its rear will support your sit bones (the ischial tuberosities – those two protrusions that bug you when you sit on a hard bench). These bones will form dents in certain types of seats. If the seat is correct for your anatomy, the depressions will be centered on the pads of the seat on either side.

While the rear of the seat supports your sit bones, the front (nose) of the seat is designed to help you control the bike with your thighs and support some of the body weight.

The problem with the nose of the bicycle seat is that it bothers many riders, both women and men. This is the part of the seat that’s most likely to compress nerves, irritate genitalia, cause chafing and generally abuse the body. Fortunately, there are plenty of seat models currently available that address the issue with various innovations.

Certain models incorporate a channel centered down the length of the seat. Others use a hole toward the front of the nose. Seats with channels and holes are often called Cutaway seats. Some seats feature soft foam or gel in the nose and soften the base of the seat beneath to reduce the stiffness. These are usually called Gel seats. The important thing to know is that if you find the seat’s nose a problem, there are models designed to remove the intrusion. Try a few until you find the model that works for you.

Not a Random Design

A lot of people look at the typical narrow bike seat found on a modern road or mountain bike and wonder what demented individual designed such an obvious torture device. That’s an understandable reaction but it overlooks the fact that the modern bicycle saddle is a sophisticated invention that took about 150 years to develop.

From the earliest days of cycling, inventors realized that having a comfortable saddle was key and they experimented wildly (see illustrations) to come up with sweet seats. As the bicycle changed in design, saddles changed and the typical seat found on today’s bikes is a product of that evolution.

Though it looks odd and maybe uncomfortable, it’s actually quite clever. The long narrow shape allows the cyclist to spin his/her legs at high rpms. A wider platform would interfere with pumping thighs. The back of the seat is just broad enough to support the pelvis and just padded enough to absorb impacts without adding weight. Because the saddle top is suspended on rails beneath the seat, there’s give in the seat top that helps suck up bumps and air can pass beneath the seat helping to cool it a little. Plus, the long top allows the cyclist to scoot forward or back to shift the pedaling position and to adjust body weight when needed to control the bike or simply for a change to rest tired butt muscles. What’s amazing is that all these features are available in something that can weigh less than 200 grams, last 10,000 miles and cost less than a good meal.

Use it, Don’t Abuse It

So, just because a seat may look scary, don’t assume it’s a stinker. First, adjust it properly and try it. Don’t hit the road and/or trail in jeans or ordinary shorts, though. Why? Because clothing such as jeans and many types of shorts have seams in the crotch area. Sitting on top of these seams puts pressure on the sensitive tissues in the groin area causing pain and numbness. Instead, purchase cycling shorts, which include padding (called the “chamois”) and are seam free in the crotch area. Underwear is not worn with cycling shorts either because, you guessed it, underwear also contains seams.

Now that you’ve got your cycling shorts, you need a couple of riding tips that will help protect your body. Don’t just head out and mindlessly pedal along. That will concentrate the pressure on the contact points, the handlebars, pedals and seat. The key to comfort is moving around regularly to shift the pressure (this goes for your hands and feet, too). Standing occasionally such as when you’re climbing, will relieve the pressure on the seat and get a whole new set of muscles working.

And any time you’re rolling over bumpy terrain, take the weight off the saddle by lifting your body slightly with your knees so that you’re in a jockey’s position on the bike. In this riding position, the seat won’t be able to slam into your groin or transfer energy from the wheels running into ruts, rocks, holes, etc., into your body.

Via – http://www.jimlangley.net/crank/bicycleseats.html