Achieving a Safe Bike Fit

There is More to Bike Safety than a Helmet

by Matt Kraus

There are many aspects of bike fit that can affect your ability to ride safely. If the title of this article resonates to you, then chances are something has gone awry with your bike riding, or the safety of your current bike fit. Deciding that your health and sexual function are important enough to warrant an improved position on your bike is taking an active step to riding in comfort and peace of mind, knowing that you are not doing bodily harm where you shouldn’t. This article will show you many ways to make your riding position safer. My credibility to write this article lies in the fact that I race bikes as an amateur, have worked in bike shops, have a Masters in Public Health, understand a decent amount about body mechanics and have a genital blood flow problem, that is healing.

When I was given the bad news from Dr. Goldstein on my first visit to the Institute for Sexual Medicine, I was more depressed from the thought of never riding again than about the injury I had sustained. I knew my injury was not beyond the point of no return and my body would heal in good time. I also knew that I injured myself while racing mountain bikes. I was now racing road bikes and knew road riding was not the source of the problem. Since first diagnosed about 1.5 years ago, my condition has improved while I continued to ride and race. I was able to continue following my riding passion by finding the appropriate saddle for me, adjusting my saddle position, decreasing the reach of my bike and adjusting my handlebar position. Since diagnosis, I have raced/placed in many Cat 3 road races and even won a national amateur cyclocross championship.

The most important decision you can make towards achieving a safe riding position is your choice in saddles. When choosing a bike saddle that works for your body, it is important to first understand the bodies mechanics applied to sitting on a bike saddle. When riding, you should be seated on your sit bones, and all the pressure of the seat should be felt there. You should not feel pressure on the area in between your sit bones, where all the important nerves and arteries are placed. A smart first step is to have a seat that works for your body type. There are a myriad of choices, and the one that works for you might be different from what works for me. Everyone has a different bone structure, and needs a different seat shape. A good seat, in my definition, is one that places all the pressure on your butt bones, and no pressure in between. When I sit on a standard saddle (a Selle Flite for ex), I can feel the pressure in all the wrong places and it is very uncomfortable for me because I know what is going on physiologically. In fact, I raced mountain bikes on a Selle Italia Flite (pretty standard saddle shape) for 4 years before I visited Dr. Goldstein. I simply did not know any better, and did not consider my saddle a problem at all, yet I was systematically causing artery damage without even knowing it.

We are all built differently. The higher-end Specialized Body Geometry saddles work well for me, but are uncomfortable for other people. Unfortunately, the only way to rate saddles is to try them for more than just a few minutes. Some forward thinking bike shops have a seat return policy, which gives you the ability to use and return a seat within a specified period of time, as long as you have not ripped it. If a local shop does not have this policy, try asking for permission from the shop owner, or see if you can use the saddle on an indoor trainer in the shop.

Once you have the correct seat, the next step is to make sure that you are not over-reaching to your handlebars. Chances are that you will need a shorter reach to alleviate unsafe pressure on your genital area, so I will assume that your next step is to decrease the reach of your riding position. When we extend our reach too far, our hips begin to rotate forward, which eventually places us in a position that is potentially damaging to our genital area. After my diagnosis, I decided to shorten my reach by about 2 centimeters. I took 1 centimeter from the stem (to a 12cm stem) and another from moving the saddle forward on its rails.

The first place to look to decrease your reach is your stem length. Stems lengths usually vary between 10-15cm and are measured from the center of the headset bolt to the center of the handlebar clamp. When I was diagnosed, I made the move from a 13cm to a 12cm stem. Another option is to effectively shorten the reach by getting a stem with a higher degree of rise, to raise your current stem. If you have a quill system, you can simply loosen the bolt that tightens the mechanicals in the headtube and raise the stem. If your bike has an aheadset system, then you hopefully have room to move some spacers below your stem. If not, another stem option is to get a stem with a greater degree of rise. Standard road stems have a 73 degree rise (which is the same as negative 17 degrees), making the stem parallel the road. If you have a stem with an angle greater than 73 degrees (closer to 90 degrees) then you are also raising the handlebar in relation to the rest of the bike. I now use an 84 degree stem, which is 11 degrees higher than my previous one. Stems also come in positive degree sizes, which are even higher, and many are reversible and enable you to flip/flop the stem (the same stem can be a negative and positive 17 degree rise). Either way, the overall goal is to raise your handlebars or move them closer, which shortens your effective reach. By shortening your effective reach, you are allowing your hips to stay as upright as possible, avoiding a forward rotation, keeping you in a safer riding position.

All cyclists have different riding styles. Some road riders ride mostly in the hoods (see picture below), while others like to ride in the drops (lowest position on the handlebars). I never was one to spend much time in the drops, so I did not have to alter my riding style too much. If you spend most of your time in the drops, then you might have to raise your handlebar height more than most, or you will always be riding in an unsafe position with your hips rotated too far down. As a rule of thumb, I would recommend that you have less than 8 cm difference between the height of the top of your seat and the height of the top of your handlebars. This ratio is best seen by looking at the side profile of your bike, and measuring the differential between your seat and the handlebars. Learning to ride in a slightly less aero position, while spending more time on the hoods, is generally safer and a small sacrifice to make. It is pretty difficult to achieve a safe position if you tend to stay in the drops for extended periods of time. Most cyclists spend time riding in the hoods- the hoods are the gizmos on your road bike where you rest your hands when you are shifting or braking – you can shorten your position by adjusting the hood height. Hoods can be moved up or down along the handlebar. To adjust them, loosen the bolt that is hidden on the outside of each hood, located under the rubber cover. A standard rule of thumb for hood placement is to have the brake lever perpendicular to the ground. I recommend moving the hoods up the handlebar a little so the length it takes to reach them is shortened, see photo.

The next variable to look at is the saddle fore/aft position. I purposely put stem length ahead of saddle position because most cyclists are more particular about the relationship of their hips/knees to the pedals than they are to the relation of their upper body, which is more benign. Therefore, people are more likely to adjust their handlebar position than the position of their saddle. Saddles have a fore and aft movement that can be adjusted by loosing the seat post bolts and sliding the saddle forward or backwards. Most seats have about 2-3 cm of room to play with. If you find that your saddle is jammed all the way forwards on its rails and have no more room, consider a different seat post. Certain seat posts are made with a layback in the design construction (see left picture) and others have a more upright design (see right picture). This means that some seat posts are designed to offset the saddle backwards, while others place the saddle directly on top of the post. You can tell which is which by looking at the location of the saddle clamp in relation to the seat post. An upright seat post can shorten your reach by 2 centimeters.

It is not structurally safe to use a saddle that is jammed all the way forwards (or backwards) in the seat post clamps, as it puts an undue amount of stress on the saddle’s rails. It is optimal to have the seat attached to the seat post near the middle of the range on its rails. Cyclists are less likely to want to move their saddle position because it can affect the mechanics of their spin. I am quite flexible and was able to slide my seat forward without encountering any knee issues or pain, not all cyclists are that lucky. If you determine that you need to move you saddle in either direction, and you are worried about your knees, try moving the saddle in increments of 3mm each week, until you reach the desired point.

The next area to address is the saddle angle. Most bike shops use the rule of thumb that the saddle should be parallel to the floor. While this generally works for setting up riders, if you are reading this, it this is not your rule of thumb. The more you can point the nose of your saddle downwards, the less risk you run of sitting in an unsafe position. Moving the nose of the saddle down attempts to match the angle of your hips as they naturally rotate forward while you ride. There is no reason why the nose of your saddle should ever be higher than the rear of the saddle. The question remains how far down should you rotate the saddle. The answer to this question depends a lot on your position. Earlier in this article, I mentioned many ways to shorten your reach. If you shortened the reach by getting a higher handlebar position, then you may not need to angle your seat down as far. If you still want lower handlebars, then you will need to point the nose downward to closely match your hip angle.

I am trying to illustrate a relationship between your handlebar height and saddle angle. If your hips are rotating downwards, then you should be adjusting your seat to match this rotation. Try to visualize this important concept. Close your eyes, and picture yourself sitting upright on your bike seat as you ride slowly. Now imagine that you are pedaling really hard (or climbing a hill), and your upper body naturally gravitates towards your handlebars as you strain to pedal harder, causing your hips to rotate downwards. This body movement will take you from a safe riding position, to a dangerous one unless your seat is angled downwards to match your hip angle. The risk to this is that your wrists will take more pressure than they would if your seat was parallel to the ground. I was willing to take that risk, and was able to condition my hands to take this pressure. Eventually they adjusted. Everyone is different and will react to this differently, but I consciously wanted to take pressure off my genital region and was glad to give that pressure to my wrists instead.

In this article I have outlined many bike adjustments to make your riding position safer, but I saved the most important bit for last. The best advice that I can give you is to increase your awareness. The more you know about your bike-fit options, the more you can do to make your position safe. The more you are aware of your position on your saddle, the less risk you will incur. Keep in mind that the more intensely you ride, the harder it is to be aware of your seated position. It might take practice to ride hard, continue to sit safely and still be able to recognize when you need to shift back to a proper position on your saddle. Even today, I am constantly checking myself to make sure that my sit bones are the only body part actually making contact on my saddle. It’s very easy to loose sight of this while riding, increasing your awareness is the only solution.

Sometimes, life is about tradeoffs. While the position I am prescribing is not the most aerodynamic, it is safer for you. While it may not be where you naturally envision yourself on your bike, it will keep you in the game longer. While it may cause some initial soreness on your butt and wrists, you should feel good about riding in a safer position. With all tradeoffs, you must ask yourself what is the most important aspect to the tradeoff. For me, it has always been about the ride. Getting better while continuing to ride was my most important goal. I can be emailed at if you live near Massachusetts and would like to schedule a private fitting session.

Primary teaching affiliate
of BU School of Medicine