Just as the squishiest running shoes aren't the most comfortable in the long run, the softest bike seats aren't the best either. If your butt hurts when you ride, there are other things to check before you buy a new saddle -- and other considerations besides how soft it is.
Photo by Daniel Oines
Here's the problem with soft saddles, as explained by bicycle guru Sheldon Brown:
Imagine sitting down on a coffee table. Your weight is concentrated on the two bumps of your "sit bones", also known as the "ischial tuberosities." These are the parts of your body designed to bear your seated weight. Most cases of saddle-related discomfort arise because the load is carried on the soft tissues between the sit bones. Imagine placing a soft pillow on top of the coffee table. Now, as you sit down on it, the sit bones compress the pillow, which yields until the sit bones are almost on the table surface again. The difference is that now, you have pressure in between your sit bones from the middle part of the pillow. In the same way, a saddle with excessively soft, thick padding can make you less comfortable by increasing the pressure between your sit bones.
Rather than going for a softer saddle, you'll first want to check that your bike is set up correctly, distributing your weight across the saddle and handlebars in a comfortable way. (Cyclists use the term "saddle" because they say a seat holds your entire rear end; a saddle supports you in strategic places.)
If a properly adjusted bike still makes your butt hurt, you'll want to shop for a saddle that matches the distance between your sit bones (which you can measure by sitting on a ziploc bag full of flour). You'll also want to choose the right type of saddle for the riding you do: casual riding, short races, or longer touring rides. Your local bike shop can help you figure out the right one for you, and in the meantime you can read more about the considerations at the link below.
My Butt Hurts When I Ride My Bicycle. What Kind of Saddle Do You Recommend? [Bicycle Touring Pro]
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