Welcome to our Ask a Mechanic column where our expert mechanic Daniel Slusser answers your bike maintenance questions. If you have a question for Daniel, please post it on our Facebook Wall or e-mail Daniel directly at email@example.com. Today’s column includes tips on keeping your rear end awake and comfortable out on the road and a video on measuring sit bone width in order to choose the right saddle.
I’m not sure if this is a common problem or not but I have a problem with my butt going numb out on the road. I don’t have any issues with other parts in that area going numb though, just my backside. It doesn’t take very long to go numb either, just 10-15 miles into a ride I start having this problem. Do I have the wrong saddle? Should I change my position? From: Paul
Rear end numbness can be a real pain in the butt. Err, I meant it can be annoying. Without seeing your position it is hard to make a recommendation but I can give you some guidelines that will help. The numbness you are describing is typically caused by either a pinched nerve or a loss of blood flow. Understanding this basic underlying cause is the key to finding a solution for it.
The easiest and most effective fix is to move around on the bike more. Get out of the saddle at least once every 10 miles and frequently change your hand position on your bars. Different hand positions will change your position on your saddle and help to keep the blood flowing better in that area. Moving fore and aft on the saddle from time to time is helpful as well. Flat saddles such as the Fizik Arione are great for this because it makes moving around much easier and more comfortable than a saddle with a big curve that only has one or two comfortable positions.
Another possible solution is finding a saddle with a better fit. The number one consideration in choosing a saddle is finding one that matches your sit bone width. Choose a saddle that is 25-30mm wider than the distance between your sit bones for the best fit. We made a video to show how to take that measurement at home with basic tools that almost everyone has on hand.
Having a saddle that is too wide is more likely to cause the problem you are experiencing as opposed to saddles that are too narrow, which typically cause numbness in your dangly bits. Another big consideration is avoiding excessively padded saddles, especially highly padded gel-filled saddles. My experience with these is that as your backside sinks into the padding, the saddle is exerts pressure on the soft tissue on your backside thereby reducing blood flow in that area. Having a firmer, narrower saddle will focus the pressure on your sit bones, which is the anatomical structure that actually holds you up when seated. If you are worried about being uncomfortable with a firmer, narrower saddle, a high quality chamois in a good pair of bib shorts will go a long way toward improving that comfort.
My last tip for you is to experiment with different handlebar setups. Upright riding positions tend to increase rear end numbness by placing more weight on your rear end relative to your hands. Lowering your handlebars and/or using a longer stem that stretches you out on the bike can help you to rotate the top of your hips forward in order to take some pressure off of your derrière.
Try each of these solutions one at a time until you begin to find some relief. After you find the one that works best, you can then combine it with the second best fix and see if that helps to improve your results even more.
Let me know how these fixes work for you and may your backside remain awake and alert on your next ride!
Daniel Slusser is a professional bicycle mechanic with over ten years of experience. He holds a bachelor’s degree in business administration from HSU and a master’s degree in history from Cal Poly. When he is not riding, wrenching, or writing he enjoys spending time with his wife and two children.