Despite everything we’ve learned about bikes, components and fit in the past 100 or so years, saddles remain one of the areas that can be hard to get right. As anyone who’s done a long ride on an ill-fitting saddle can attest, choosing the wrong one, or setting up the right one incorrectly, can be disastrous.
Kyle Russ, a biomechanical engineer, and Matt Gehling, a bike fit specialist, work at Trek Bikes in the USA and know more about saddles than most. Together, they offer different but complementary perspectives on saddle design, common problems, and how to find one that best matches your body and your riding style.
Given the challenge many people have in translating sensations on the bike to specific words or causal factors, we’ve kept this interview longer than normal. As far as saddles are concerned, sometimes it’s helpful to hear the same thing in different ways or know some of the reasoning behind various designs. This makes it easier to translate experiences that are felt (particularly painful ones) into productive conversations or corrective courses of action.
Read on to learn more about recent research, design innovations and tips for ensuring a good fit, or simply scroll straight to the questions that align most with your own interests.
Thanks to both of you for chatting with us. Can you briefly explain a little about your roles at Trek to give your comments some context?
Kyle Russ: I’m a biomechanical engineer for Bontrager components. I work closely with mechanical engineers and industrial designers on saddles, grips, shoes, insoles, chamois, and gloves.
Matt Gehling: I’m the Precision Fit Product manager at Trek. I’m responsible for developing tools and education programs that enable our global retailers to implement a successful fit business in their stores. I also lead a team that is responsible for providing fit support to Trek sponsored professional athletes.
What are the most common problems that occur due to a badly fitting or poorly designed saddle?
MG and KR:
1. General saddle discomfort, especially in the soft tissue area. This may lead to pain or numbness in the genital area.
2. Low back discomfort, often from posteriorly rotating your pelvis away from a bad saddle. The discomfort comes from having a “round” spine and compression of the front of the intervertebral discs.
3. Poor spinal posture. [The rider has] either never shown a “neutral” spine or [has] poor core strength. [As in 2, the discomfort comes from having a “round” spine and compression of the front of the intervertebral discs.]
4. Saddles that are too narrow don’t properly support the bone structure of the pelvis.
5. Saddle sores. These could be due to excessive friction from the dynamics of pedalling (this may be due to a saddle that’s too wide), or from excessive pressure on the bone structure (this may be due to a saddle that’s too flat or hard).
What are some of the less common or more extreme problems that can occur?
KR: A more extreme problem would be due to damage to the nerve structure in the perineum of a male or female cyclist. It’s absolutely critical to relieve pressure in this area. If a rider is continuously experiencing numbness of the genital region, he or she should see a doctor and get a proper bike fit from a knowledgeable, trusted fitter.
Can you explain some of the main reasons these issues occur?
MG: The saddle too narrow, the saddle doesn’t relieve soft tissue pressure, or the saddle is the wrong shape for the rider’s position.
KR: As Matt stated, this may happen if the saddle is too narrow, or if the saddle does not provide a proper relief zone by way of a “cut out” or “split nose”.
Additionally, the saddle might be the perfect match for the rider, but he or she is sitting too far forward on it. If the rider sits too far forward on ANY saddle, the ischium of the pelvis will not be supported by the saddle (think “sit bones” hanging off the sides), and the perineum will experience excessive pressure.
If a rider is performing long riders, he or she should be supplementing the bike rides with core work so that a proper “seated strategy” can be adopted (sitting back on the saddle, anterior pelvic tilt, and straighter spine).
How have saddle design and fitting systems developed over recent years to combat these common, and less common, problems?
MG: Pressure mapping has been the biggest thing that has helped us. Being able to visualise how a person is actually interacting with the saddle has been huge. We can now develop a prototype, test it, and validate whether it is doing what we’d like or not.
Kyle coming on board as our in house biomechanical engineer has really pushed our saddles to the next level by bringing in a more scientific approach to saddle design and testing.
KR: The use of pressure mapping equipment has been absolutely essential in not only the development of product, but the knowledge base of the company in terms of how riders interact with their components. We additionally use motion capture video and high speed cameras to get a sense for the joint angles and dynamics involved, meaning that this is not a static interaction.
We also collaborate with researchers in Frankfurt to perform Finite Element Analysis on computer models of actual humans. This gives us insight into the stresses and strains of the internal tissues of the rider for a given design of the product.
As a result of all of this research, saddles across the industry have become much better at distributing pressure to the bone structure of the pelvis and avoiding the soft tissue areas.
Pressure mapping has certainly made for some big leaps in saddle design and the research and development process. Can you talk us through any of the more surprising findings?
KR: Using pressure mapping equipment consistently for over five years now has allowed us to understand small differences in pressure that may have big effects on the rider. For instance, if the gradient of pressure to the outside of the bone structure is very steep, this is an indication that the rider’s bone structure is running off the edges of the saddle. Think of a bright red hot spot that immediately becomes a cooler, darker colour to the outside of the bone, rather than showing a gradual change of colour.
Your first impression as the researcher might be, “The saddle is obviously too narrow, and it needs to be wider to support that bone structure.” However, sometimes a wide saddle forces the rider to sit too far forward on the saddle, and therefore the ischium of the pelvis runs off the sides. Sometimes switching to a narrower saddle allows the rider to sit on the back of the saddle as the saddle is intended, and the rider therefore gets the proper support he or she is looking for.
Due to this research and the designs that have followed, it seems like an increasing number of riders are opting for unisex saddles, or saddles marketed at the opposite gender. Can you provide some insight into why gender specific saddles might not be so specific after all?
MG: Paraic McGlynn has a really good quote on this: “Your arse doesn’t have eyeballs.” Your pelvis really just cares about how it is supported.
We’ve found through testing that as a pelvis gets wider, it needs different things for saddle design. The thing is, it doesn’t matter if it is a wide female pelvis or a wide male pelvis, they both need the same support and soft tissue relief. The biggest difference is that the shallower pubic arch on a woman necessitates better soft tissue relief sooner, but there is no reason a more pointed male pubic arch wouldn’t benefit from the same thing.
KR: For men and women, the fundamental goal of the saddle is the same: to distribute pressure to the bone structure and relieve pressure from the soft tissues. This means that men and women alike benefit from well-designed “cut out” saddles.
While the pelvic structure for women tends to be wider and shallower (front to back) than the average male pelvis, the shape of the bone structure for both vary greatly. Therefore, the shape, width and material properties of the saddle are the most important factors that affect whether or not a particular saddle supports the rider properly.
How have these recent developments in thinking about saddle design and fit changed the ways you can communicate with athletes and consumers?
KR: As our understanding of saddle design has matured, so has our messaging to athletes and consumers. The question is no longer, “Do you want a saddle with a hole in it, or one without a hole in it?”
What matters is identifying that pelvic angle and width of the ischial tuberosities of the rider. We know we can make a rider more comfortable when we answer those two questions, and the pressure mapping equipment and motion capture video is a visual way to show that the to the athlete or consumer and have it resonate immediately.
Despite what we have learned about saddles, “What saddle should I choose?” is still one of the most commonly asked questions on cycling forums, and usually receives a tonne of different replies and recommendations. Do you have any advice for someone overwhelmed by choice?
1. Get a wider one. I’m not talking about a huge cruiser saddle, but in general, wider works better and gives better support for most people. For men, that is a 140 – 150 mm saddle. For women, that is at least a 150 – 160 mm saddle.
2. Get one with a cut out. In general, cut outs help riders with a more performance position.
3. Play with the angle. It will help comfort when you find the right spot. 0.5 degrees can make a big difference. In general, play with angle down. Start at -1.0 degree, go up to -3.0, but don’t go so far that you feel like you’re sliding off your saddle.
KR: Knowing how to get a rider on the proper saddle is the holy grail of saddle development. The two most important things to know are the desired pelvic angle of the rider on the bike, and the ischial tuberosity width of the rider’s pelvis. The latter is easier to find out.
Most saddle brands make a sizing device that’s free to use and identifies ischial tuberosity width. The desired pelvic angle of the rider, however, is either identified by a fitter, or the rider can assume if they’re more “aggressive” or “moderate” in terms of how much they rotate their pelvis on the saddle. This is critical because pelvic rotation angle determines which portion of the pelvis makes contact with the saddle. A saddle designed to support the ischial tuberosities will not have the same shape or materials as a saddle designed to support the pubic rami of the pelvis [if the rider rotates further forward].
What other steps can riders take to improve performance and increase their comfort on the bike, in relation to their saddle?
MG: Get a fit! And don’t forget about your feet. Proper shoe set up (cleat alignment, insole) can actually do a lot for saddle comfort.
KR: A rider looking to improve performance and gain comfort on the bike should absolutely get a bike fit. This is the proper way to find out how you as the rider are interacting with your bike.
A free, simple thing that I recommend is putting the bike on the trainer next to a mirror (side view). Most riders have no idea what they look like on the bike. A rider can try to rotate into and away from their saddle to both see and feel the differences on the saddle, and in their back. The rider can also move forward or back on the saddle and observe the same things. A rider with low back pain may have an “Aha!” moment when he or she sees how round his or her spine looks in the mirror.