A saddle that suits your needs perfectly is one of the holy grails of cycling. That makes getting a saddle that complements your rear end one of the most important upgrades you can make. It can be the difference between enjoyable, comfortable rides and a very painful posterior, especially on long days in the saddle.
In an ideal world, it is best to try a new saddle before buying it. However, it's highly unlikely your local bike shop will have every option out there and even less chance they'll allow you the luxury of "trying before buying", even if they have a lenient return policy. So, where do you start?
One of the most important things you can do to aid you in your saddle search is to measure your sit bones, as that will enable you to look for a saddle that is the correct width. But, what are my sit bones, you ask? And how do I measure them? Read on to find out.
What are sit bones?
So firstly, if you don't know, the clue is in the name, but your sit bones, or to give them the correct medical name, the Ischial Tuberosity, is the V-shaped bone at the bottom of the pelvis that makes contact with a surface when you sit down. If you’ve ever sat on a hard seat for a long time, you’re no doubt familiar with this pokey bone and the discomfort you can get.
Bike saddles are designed to provide optimal support to the sit bones for maximum rider comfort. Too narrow and the sit bones are unsupported, causing the rider undue muscle and tissue stress. Too wide and the sit bones can rest awkwardly on the edge of the centre channel, where saddles offer little to no padding.
How to measure sit bone width using cardboard
This is both the most low-tech and the most accurate at-home method. Grab a flat piece of corrugated cardboard and place it on a flat surface. Sit down on the cardboard, and settle in so your sit bones make an indentation. You can even pull up on the chair to press your butt and sit bones into the surface.
Stand up and use a pen to circle the indentations. Mark the approximate centres with a plus sign, and use a ruler to get the distance between the centre marks. Make sure your clothing isn’t giving a false result; for example, jeans rivets poking the cardboard instead of your sit bones. A firm chair works best, so don’t bother trying to do this test on the couch. If you’re not sure if you did the test right, grab a fresh piece of cardboard and do it again just to make sure.
The cardboard sit bone test works similarly to the high-tech, pressure-sensitive devices saddle brands have at their disposal, so the results are generally quite accurate.
How do I use my sit bone width to find the right saddle fit?
Every brand provides slightly different information when it comes to saddle width. Some offer a range of sit bone widths for each size, while others simply give the overall width of the saddle. In most cases, your saddle should be wider than your sit bone width by 15 to 20mm. This will ensure you’re not right on the edges of the saddle, where your sit bones will be poorly supported.
If after purchase, you find that a saddle is uncomfortable even though it’s the right size, check to make sure you have the saddle positioned appropriately. For example, if it is installed too far back away from the bars, your sit bones could be resting closer to the nose of the saddle where it narrows. The saddle angle can cause similar problems if the tilt causes you to slide toward the front or back of the saddle and away from the widest spot where sit bones are supposed to rest.
Having done the test myself on two of my saddles, it was an interesting result. My gravel Syncros saddle shows a slightly narrow fit, while my Scott mountain bike saddle is wider with an almost perfect fit. Although there are only a few millimetres in it, and both saddles seemed fine to me when I rode, it was definitely worth checking and I've fine-tuned my saddle position as a result. It also means when I come to upgrade, I have the ideal saddle width in mind.
