Typical saddles are composed of a few identifiable components.
The shell creates the shape of the saddle. The nose of the saddle is the forward most part. It is usually rounded. The shell can be made from several materials.
Most modern bicycles have a saddle that has a shell made from a moulded piece of plastic, such as nylon. Carbon fiber may also be used.
Leather saddles do not have a hard shell. Instead a moulded piece of thick leather is stretched, like a taut hammock, between the front and rear ends of the rails. Traditional leather saddles such as those made by Brooks have been used for many years. Such a saddle is generally more comfortable after a break-in period during which it conforms to the shape of the rider, so long as the basic shape is right to start with.
There is usually, but not always, some form of padding on top of the hard shell, often closed cell foam or gel, and then a fabric, such as lycra, vinyl, artificial leather, or leather cover.
Some saddles, especially those designed for hard use e.g. mountain bike or BMX style riding, will have a tougher material, such as kevlar, to withstand abrasion on the nose and the widest parts of the rear.
The rails of a saddle are the connection point to the rest of the bike. They run along the underside of the saddle from the nose to the rear. Most saddles have two parallel rails that the seatpost clamps to. They provide fore and aft adjustment of the saddle, usually an inch or so (2.5 cm). Rails can be made of steel, titanium, aluminum,magnesium, or carbon fiber. Rails may be solid or hollow.
Saddle rails are typically a 7 millimeter diameter, an industry standard for some time. Today some companies are introducing saddles that use carbon fiber rails that have a larger diameter or even an oval shape requiring use of a seat post specifically designed for the particular rail diameter and/or shape.
A recent innovation, used with carbon shells and rails, is for the rails to be integrated into the shell for their entire length. Another is an interface called pivotal. Pivotal seatposts are common on BMX bikes. They have a concave semicircle of ridges at their top that matches the convex semicircle of ridges on the bottom of a pivotal saddle. The two semicircles are held together with a bolt to attach the saddle to the seatpost. A recent rail type is the i-beam; it extends almost the entire length of the saddle and uses a single clamping bolt. Because the beam is long and the clamp narrow, the i-beam mounting affords a wide fore-aft adjustment range.
A saddle may contain suspension components, such as springs or elastomers between the rails and the shell, to help absorb vibrations transmitted by the frame and seatpost.
By using interchangeable elastomers with variable densities the suspension saddle can be tuned to the rider’s weight and riding style.
The position of the saddle should be adjusted relative to the bottom bracket, not to the ground or handlebars. For example, if the reach to the handlebars is too far, it is better to get a shorter stem than to move the saddle forward of its ideal location. More accurately, saddle height should be adjusted relative to the position of the pedals as fitting different pedals or different length cranks would also mean the saddle needs to be re-adjusted. In practice, the distance from the top of the saddle to the centre of the bottom bracket is used as the saddle height, e.g., setting up a new bicycle using measurements from another, as this is easier to measure. Other methods and calculations are used for determining seat height, such as LeMond’s formula.
The saddle height should be set so that when pedaling, the legs have a slight bend even when the pedals are at their furthest distance. This means that if the saddle height is properly adjusted the rider cannot place both feet flat on the ground when seated on the saddle. If they can, their saddle is too low.
The saddle should be nearly level, although the height of the handlebars and style of cycling will cause this to vary.
Fore and aft
Conventional wisdom dictates that the saddle should be positioned so that when the crankarms are horizontal and the feet are on the pedals the kneecap of the forward leg is approximately above the pedal spindle in a vertical line. However Keith Bontrager argues that there is no anatomical basis for this. Furthermore, the relative position of saddle and bottom bracket varies between road racing, track and triathlon bicycles.
Adjustment range differs for each saddle, and the purchase of a saddle for an increased range of adjusment is often confused by its different shape. In comparing them, it is the range of adjustment of the comfort point that needs considered, and because its position is a largely subjective property, giving it proper attention is difficult to do. Advertisers claim that i-beam saddle designs can give up to 200% more adjustment range than double rails.
While small saddles are available for children’s bikes, the primary size parameter for adult saddles is width. Performance saddles, such as for racing, tend to be narrow. Comfort saddles, often found on hybrid bicycles, tend to be wide.
Women-specific saddles have been recently introduced by several manufacturers. These incorporate a variety of differences designed to suit female anatomy. These differences may include a wider seat area, shorter nose, and center relief.
While riding an upright bicycle improves the cardiovascular system and can therefore actually improve the erectile function among men, riding a bicycle for prolonged periods of time with a poor cycling technique can still cause problems for both men and women due to a reduced blood flow in the crotch area. Some male riders recent survey data indicates around 5% may ultimately get erectile dysfunction problems if a poor cycling technique is used with prolonged pressure on the perineum. Both men and women may also get reduced sensitivity in the crotch. A sign of these problems can sometimes be a tingling sensation in the area when stepping off the bicycle after a ride, as blood flow surges back into the area again. This issue is more related to the cycling technique than the saddle type, although there are special, more anatomically correct, designs to relieve crotch pressure as well. Examples of such designs include the cutaway saddles and noseless saddles. Cutaway saddles resemble regular saddles in their design, but with the middle part cut out to reduce pressure on the perineum among men. Noseless saddles are basically two separate saddles next to each other, with one smaller “saddle” per buttock. Such saddles achieve a similar relief of pressure by using a different design.
Some useful techniques to reduce crotch pressure while cycling include:
Ensuring the saddle is roughly horizontally aligned, or only slightly nose up. The nose too upwards aligned will directly increase the perineum pressure, while a downwards alignment will reduce the sit bone support of the pelvis, again resulting in an increased perineum pressure.
Standing up occasionally, such as on hills and when accelerating.
Adjusting seating position from time to time. For example, sitting closer to the rear when cycling on hills and only sitting on the nose for brief periods.
Sitting up now and then without leaning forward as much.
Erectile dysfunction and genital numbness
Bicycle riding has been correlated with genital numbness, erectile dysfunction (ED) and perianal hematoma , and several studies have shown that long-distance cyclists have an increased incidence of ED as compared to the general population. ED and genital numbness result from compression of the cyclists’ perineal region while sitting on their saddles. To alleviate the problem, manufacturers have designed a number of bicycle saddles that purport to allow greater blood flow through the pudendal artery. These saddles vary in shape, width, and padding and have been studied to determine any actual effects on cyclists’ health. (However, most current research excludes discussion of female sexual dysfunction and genital numbness.)
The studies have shown that wider saddles tend to increase penile blood flow while cycling, though wider seats also induce chafing and impede a cyclist full range of leg motion. A downward-tilted saddle relieves pressure on the perineum and the “sit bones” (ischial tuberosities), thus improving a cyclist’s perineal blood flow. Most saddles include padding, generally foam or gel. Gel padding tends to distribute pressure in the perineum and provide higher levels of penile oxygenation than does foam padding. However, width and design have proved to be more important than the amount of saddle padding in determining the intensity of perineal distress the cyclist suffers. In fact, some researchers have postulated that extra padding, foam or gel, can result in an increased prevalence of pain in the sit bones.
While not adopted by competitive cyclists, no-nose saddles have been shown to improve erectile function among ED-suffering cyclists. A 2008 study measured ED and genital numbness among bicycling police officers who used traditional saddles versus the same officers after using no-nose saddles for six months. The number of officers experiencing genital numbness fell from 73% to 12%. Cases of erectile dysfunction also fell significantly. This research won the Bullard Sherwood Award for intervention research.
Gallery of saddle types
A modern mountain bike saddle without any explicit suspension.
A Selle San Marco saddle for women
A hard plastic BMX saddle without padding or cover.
A Brooks leather saddle.
A Koobi PRS bicycle saddle showing interchangeable elastomer suspension.
A wide well-padded saddle.
A BMX saddle with central padding.
A saddle with spring and elastomer suspension and rails with an extra curve.
A saddle with an elaborate looking elastomer suspension.
Ergonomical saddle EasySeat II (Hobson)
A “banana seat”.
Bike saddle with additional padding.
^ Brown, Sheldon. “Glossary: Saddle”. http://www.sheldonbrown.com/gloss_sa-o.html#saddle. Retrieved 2009-05-28.
^ “Selle San Marco Handmade in Italy since 1935”. http://www.sellesanmarco.com/. Retrieved 2007-03-29.
^ “Brooks England Since, 1866 Saddles, Bags, Etc.”. http://www.brookssaddles.com/. Retrieved 2007-03-29.
^ “Koobi Saddles Handmade in Italy”. http://www.koobi.com/. Retrieved 2007-07-24.
^ “A Comfortable Saddle by Sheldon “Comfort” Brown”. http://www.sheldonbrown.com/saddles.html. Retrieved 2007-03-29.
^ “Keith Bontrager article on Sheldon Brown’s website”. http://www.sheldonbrown.com/kops.html. Retrieved 2007-06-27.
^ “Women’s Cycle Racing Association, FAQ, What’s so special about these “women specific” saddles?”. http://www.wcra.org.uk/faq.htm. Retrieved 2007-03-29.
^ “Research On Bicycle Saddles And Sexual Health Comes Of Age”. http://www.sciencedaily.com/releases/2005/08/050824080847.htm. Retrieved 2007-03-29.
^ a b c Gemery, J., Nangia, A., Mamourian, A., & Reid, S. (2007, January). “Digital three-dimensional modelling of the male pelvis and bicycle seats: impact of rider position and seat design on potential penile hypoxia and erectile dysfunction.” BJU International, 99(1), 135-140.
^ a b c d Breda, G., Piazza, N., Bernardi, V., Lunardon, E., & Caruso, A. (2005, September). “Development of a New Geometric Bicycle Saddle for the Maintenance of Genitalerineal Vascular Perfusion.” Journal of Sexual Medicine, 2(5), 605-611.
^ Schrader, S. M., Breitenstein, M., & Lowe, B. (2000). “City of Long Beach Police Department.” Health Hazard Evaluation Report 2000-0305-2848. National Institute for Occupational Safety and Health.
^ Tolme, P. (2005, October 31). “DON’T BE A SOFTY.” Newsweek, 146(18), 66-66.
^ “Standard bicycle seat can lead to erectile dysfunction.” (2007, June). Mayo Clinic Health Letter.
^ a b Dettori, N., & Norvell, D. (2006, January). “Non-Traumatic Bicycle Injuries: A Review of the Literature.” Sports Medicine, 36(1), 7-18.
^ a b c Huang, V., Munarriz, R., & Goldstein, I. (2005, September). “Bicycle Riding and Erectile Dysfunction: An Increase in Interest (and Concern).” Journal of Sexual Medicine, 2(5), 596-604.
^ Wiley-Blackwell (2008, August 8). “No-nose Bicycle Saddles Improve Penile Sensation And Erectile Function In Bicycling Police Officers.” ScienceDaily. Retrieved August 22, 2008.
Bicycle Saddles and Reproductive Health
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Cycling performance tips: choosing and adjusting your saddle
Bicycle saddles and comfort
Saddle seats and erectile dysfunction: the myth exploded
“Bicycling, saddles, impotence… What we think about it all!”
A Comfortable Saddle by Sheldon “Comfort” Brown
Categories: Bicycle partsHidden categories: All articles with unsourced statements | Articles with unsourced statements from May 2009