A Treatise on Design Elements
Choosing a saddle is one of the most daunting tasks faced by a cyclist. There are several elements that all work together to make a saddle comfortable… or not. Each person’s physiology is unique, but there are certain elemental design features that generally apply to all riders. Recently, Koobi, a marketer of quality saddles, put together a description of these elements. Portions of that discussion are presented here. While this is not intended as a formula for choosing the correct saddle, understanding the elements of saddle design may help you determine which one is right for you.
Elements of Saddle Comfort:
The base of the bicycle saddle is the foundation on which all of the other elements are built. You can shape it a hundred different ways, make it big or small, long or short, wide or narrow, and mix in carbon, but it is still the base. There are four fundamental attributes of the base that contribute to comfort that we will discuss.
- Base dimensions and width
- Base shape & contours, including the nose
- Base relative flexibility
- Base relief area
Bicycle Saddle Width
The basic concept here is that your “ischial tuberosities” commonly called “sit bones” should primarily carry your weight when sitting on a bicycle seat. Different people have different widths of sit bones and in general women’s tend to be wider than men’s. A well designed bicycle seat will accommodate these variations. The bike saddle also needs to accommodate variations in riding position through the various phases of your ride. A saddle that only accounts for the width of your sit bones would be too skinny for most cyclists. Koobi has always made different width saddles and we know how saddle width contributes to comfort.
Choosing Your Bicycle Saddle Width
How does the cyclist know if he is in saddle nirvana on his bicycle saddle width? If the saddle is too skinny it well feel like you are sitting on a horizontal pipe, like the saddle wants to cram up your crack. Your sit bones should carry the weight not your crack. It will feel lousy!! If the saddle is too wide you will tend to get a chafing of the skin on the upper part of your legs like your upper thighs are getting rubbed raw. Research has shown that a bicycle seat design with a wide platform and narrow nose will produce a saddle that is comfortable for the vast majority of riders. (So why don’t more saddle makers design them this way? Who knows?)
Bicycle Seat Length
Over the past 100 years there has been a variety of lengths of bicycle saddles. Conventional saddles have settled into an average length of around 27 cm in the past 20 years or so. The length of the saddle is still varied slightly for specific applications such as Triathlon saddles or woman’s saddles but in most cases it still settles into the conventional lengths.
Women’s Bicycle Saddle Length and Width
Unless you are a very small person, say less than 4 foot 6 inches that there aren’t many advantages to the shorter saddle. For this small population of shorter or smaller people, there are children’s saddles on the market. As further confirmation it is interesting to note that Terry Saddles, who market themselves specifically to women, has almost no difference in length and width between their men’s and women’s models.
Bicycle Saddle Base Shape
The overall shape and contour of a saddle influences how it feels. Ideally a saddle shapes should be such that when you sit on it. Your “sit bones”, also called “ischial tuberosities”, are well supported. In other words your sit bones carry your weight most of the time. While other portions of your bottom will carry some of your body weight, some of the time, ideally your sit bones carry most or your body weight most of the time.
Moving Around On Your Bike Saddle
Cycling is a dynamic activity. Your position on the bicycle saddle will change throughout the various phases of your ride. Moving is one of the important aspects of creating comfort in your cycling. You see if you sit in the exact same position, even if it is on your sit bones then you tend to cut off the circulation to that spot. Ouch that hurts, and numbs after an extended period of time. You need to move about.
A Bike Saddle Designed for Movement
A well designed bicycle saddle will have contours that promote movement. The ideal profile of a saddles is relatively flat. This profile is the best for both promoting movement and for supporting your “sit bones” during the various phases of a ride. As you are standing on the side of the bike looking at the side view, a saddle should be nearly flat. Some saddles have a hammock like shape. The hammock shape will feel nice in the parking lot test but it cradles your bottom, holding it. As the ride gets long this cradle shape makes it harder to move about. You tend to get stuck in one spot. Gradually this lack of movement puts pressure on the same spot on your body cutting off circulation. Another shape that is evolving into saddles is where the back of the saddle is scooped up. This shape will also reduce your ability to move about on the saddle.
The Horn and Sides of a Bicycle Saddle
Another area of shape that will influence comfort is width of the nose (also called the “horn”) and how the rear of the saddle contours for your upper thighs. A well designed saddle will have a horn and sides that allow you both maximum control and maximum mobility. The nose of the saddle helps you to balance and steer the bike and keeps you from falling off the saddle when you hit a bump.
Nose-less Bicycle Saddles
A novel saddle shape showing up in the last few years are saddles with out a nose. The concept is the nose of the saddle puts pressure on your soft tissue region so to have no pressure have no nose. Although this is correct, you forfeit the balance and control that the nose provides.
Bicycle Saddle Function – Base Flexibility
To understand how the base of the bicycle saddle contributes to the overall comfort, let’s look at how the saddle absorbs energy. When your bike goes over a bump a portion of the energy is transmitted through your bike into the bicycle saddle. Various elements of the saddle absorb this energy including the cover, foam, rails, and the base. The flexibility of the base becomes an important factor in producing a comfortable saddle.
Bicycle Saddle Base Flexibility vs. Foam Padding
There are a number of companies on the market that use very thin foam on top of a moderately thin base. The theory behind these saddles is that the comfort is derived from flexibility in the base. That flexing in the base acts similar to foam, absorbing bump energy. The first challenge that these saddle makers have to overcome is an international Manufacturing standard that requires saddles to function for a 220 pound (100 kilo) person. The first challenge is that it is a huge problem to make a saddle that functions for a 220 lb person and still be flexible for a 180, 160 or 140 pound person. The second challenge is that a saddle may be very flexible for a 180 pound person but will be stiff for a 155 pound person & too flexible for a 205 pound person. These companies don’t rate their saddles as soft, med or firm. Nor do they rate them for a cyclist by their body weight. Due to these two problems, in the end the cyclist has a one size fits all. Ride them till you find one that is flexible for your body weight. The theory that flexibility in the base of a saddle should absorb energy is a solid theory. The challenge is bring it to market so that it will work for a vast range of cyclists.
Bicycle Saddle Relief Area – The Concept
Research, testing, and common sense all confirm that the contact points on a bicycle saddle have a significant impact on comfort. The human anatomy was designed to sit on the “ischial tuberosities”, commonly called the “sit bones”. A well designed saddle will support the rider’s weight on their sit bones and minimize the amount of weight carried by the soft tissue region. Testing has shown that a center-forward relief area in the bicycle saddle is effective in reducing the soft tissue pressure while cycling.
Bicycle Saddle Relief Area – In the Beginning
Testing and research has shown that the optimal location for the cutout is the center of the saddle going forward. In 1997-1998 there were only two companies that had any kind of saddle with a relief area. They were Selle San Marco with a diamond shaped cutout in the center of the saddle and Terry saddles with a large cutout in the center of the saddle. Terry called their saddle the Liberator. Both of these saddles had the cutout more or less in the center of the saddle. A few years prior to this, Selle Italia had a saddle called the Mythos, which had a triangle shaped cutout in the rear of the saddle. Also in 1998-1999 a marketing company that specialized in bicycle products hired a marketing person who doctored on the side named Dr Minko. They borrowed Selle Italia’s Mythos rear cut out relief area and produced a line of saddles that they marketed as Body Geometry by Dr. Minko. They created a series of ads that gave the impression that cyclists were at risk of impotence and that their doctor-designed saddle would not allow this. Did they ever produced any independent peer reviewed evidence that their doctor-marketed, Selle Italia patented, rear cutout would reduce the chance of impotence? Don’t think so.
Bicycle Saddle Relief Area – The Evolution
In the following years 1999-2005, Specialized gradually moved their cutout forward. They came out with a dizzying array of models changing models every year, moving the cut out farther forward each year. Currently their cut out is center and rear. During the same time period most of the industry did the same thing with their model line up. They came out with numerous models, gradually moving the rear cut out forward to center of the saddle. Recently at least three companies have a marketed nose cut out design. Koobi, Selle SMP & ISM.
The Function of Foam on Bicycle Saddles
Almost all bicycle saddles on the market today have fabric covered foam on top of a plastic/carbon base. At its most basic function the foam cushions the ride between the cyclist & the hard base. This most basic of ingredient to comfort is also probably the most misunderstood ingredient. The vast majority of cyclist and bike shop employees assume that softer foam equals a more comfortable ride. This is far from realty.
Bicycle Saddle Foam Behavior When You Ride
Closed cell foam is a form of rubber with trapped air bubbles. When there is greater volume of air bubbles then there will be less rubber and the foam will be softer. The problem is that during a ride any foam will gradually collapse. The rate of collapse depends on the following variables:
- Weight of the rider
- Length of the ride
- Age of the bicycle saddle
- Density of the foam.
In other words the more you weigh, the longer the ride, the older the bicycle saddle and the softer the foam; the greater rate that the foam will collapse and the cyclist will be sitting on hard collapsed foam in top of a hard base.
Bicycle Saddle Foam Density
When considering these 4 variables, the density of the foam is the only one that can be altered in the design of the saddle. Firmer density foam will hold up longer without collapsing, providing a cushion between the rider & the hard base. Therefore the firmness of the foam should increase with time in the saddle. Coincidentally if you are riding longer, your conditioning also increases. If you are not cycling that much your rear end will not get conditioned enough for the firm foam & you really will not need the firmness.
The Right Bicycle Saddle For You
As a rule of thumb, if you cycle less than 3 hours per week then go for a soft saddle. If you cycle 3-6 hours per week then go for a med padded saddle. If you cycle greater then 6 hour per week then you are a excellent candidate for a firm padded saddle. Also, If you weigh less than 150 lbs, then you may be more comfortable on a softer saddle. If you weigh more than 200 lbs then you may be more comfortable on a firmer saddle.
The Traditional Bicycle Saddle Tests
The two most common tests that consumers use when purchasing a saddle are notoriously bad indicators of the correct saddle for them. These 2 are
- The legendary thumb test
- The ride around the parking lot test.
Gel Bicycle Saddles
Gel has been used extensity in bike seats for the last 10 years or so. Gel has a soft touch & thus does very well in the thumb test & the parking lot test. It has what has been described as a trampoline type affect, spreading the pressure out and making the bicycle seat feel softer while providing a cushion between the cyclist and the hard base. One of the complaints about gel is that it weighs more and many cyclists don’t feel the added comfort for the additional weight. Another complaint is that some gels tend to harden over time & feel like a piece of car tire in the saddle. In the last few years the quality of gel has improved so this is not as common. Many cyclists swear by gel, others prefer to swear at it.
Ultra Light Weight Bicycle Saddles
In the last few years several companies have produced ultra light weight bicycle saddles that feature a thin layer of dense foam on top of a carbon or plastic base. These bicycle saddles provide limited comfort by the shape and flexibility of the base. If your focus is extreme light weight and you have a high pain threshold then this type of saddle may work for you.
Bicycle Saddle Cover Material
There are applications where the bicycle saddle cover material is an important factor. For most applications a leather bicycle saddle cover will be the most comfortable, however for high moisture situations such as triathlons, or for harsh mountain biking situations, other bicycle seat cover materials will result in more comfort and durability.
Common Bicycle Saddle Materials
The most common cover materials for bicycle saddles are leather, Lycra, Kevlar & a variety of imitation leathers. Higher quality bicycle saddles will primarily use leather, Lycra, and Kevlar with imitation leather being used for inexpensive, low quality bicycle seats.
Leather Bicycle Saddles
Most cyclists feel that leather bicycle saddles have the best combination of durability and beauty. Leather bicycle saddles are tear and wear resistant, have a good touch and feel, and do a good job of managing a moderate amount of moisture. Leather also has just a slight amount of tackiness to keep the saddle from feeling too slippery. So the rider doesn’t feel like he is sliding off the saddle.
Most quality bicycle saddles have a highly durable heavy leather cover. During the first few rides, the saddle will feel noticeably firm like a new leather shoe. Over time, the leather will soften and conform to your body’s shape.
Kevlar Bicycle Saddles
Kevlar is used for its tear resistance. Kevlar has a rough texture that is not ideal for an overall bicycle saddle cover material. It is common to use Kevlar along with another material on the corners of the bicycle saddle to increase the overall durability.
Lycra Bicycle Saddles
Lycra is commonly used for high moisture applications such as triathlon saddles. Lycra also gives the cover a softer feel that is similar to gel. Denser foam will feel softer when covered with Lycra. However, since: Lycra is susceptible to tears, it is common to use Kevlar on the corners for increased durability.
Imitation Leather Bicycle Saddles
Imitation leathers have a big range of quality. There are a few that work quite well & there are other’s that are rather cheesy. The two main advantages of imitation leather is lower cost & generally better resistance to high moisture. Disadvantages are, they wear poorly, and can have a very slippery almost waxy feel to them making them slippery.
Bicycle Seats with Embroidery and Seams
Several years ago saddles were made with a myriad of embroidered logos. These had the advantage of the rider not slipping off the saddle. In the last 8 years or so the industry has gone away from embroidery on the seating area of the saddle. On a rare occasion cyclist will comment about feeling a seam on a saddle.
Side Note: Cycling Shorts
In the last 8-10 years the manufactures of cycling shorts of have used thinner Lycra. This gradual thinning of cycling shorts makes them generally less durable, generally more breathable & overall more expensive. Bicycle saddles that are rough or abrasive tend to wear through these shorts more quickly.
How a Bicycle Saddle Functions
To understand bicycle saddle rails, let’s look at how the whole bike saddle functions. Consider your last ride. When you hit a bump the saddle cover material flexes, the foam compresses and cushions, the base flexes, and the rails flex. These elements work together so that the bicycle saddle absorbs the energy in the bump instead of transmitting it to the rider.
Bicycle Saddle Rails Are Like Leaf Springs
The leaf spring design is simple, reasonably lightweight, durable, and inexpensive. The rails of a well designed bicycle saddle should flex like leaf springs. As such they possess the same properties advantages and disadvantages as leaf springs. Stronger springs are stiffer, absorb less energy, and have a poor ride quality. Flexible springs absorb more energy and have a nicer ride but are not as strong. Being a spring, the bicycle saddle rails will fatigue and can break. Excess weight and improper mounting can cause the rails to break prematurely. Typically rails from Chinese manufacturers are strong but very stiff and harsh to ride.