Riding a bike should feel good.
Many people have pain or discomfort from poor saddle fit.
The Pelvis
In the sketches below, you can see the shape of a pelvis.
The seat bones and pubic arch is where you contact the saddle.
Notice that it's wider for women than for men.
Feel where your seat bones are, the shape of your pelvic arch, and the soft tissues in between.
| Men | Women |
|---|---|
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| By Henry Vandyke Carter - Henry Gray (1918) Anatomy of the Human Body) | |
Upright position (90 - 60 deg)
When riding upright, the bottom of your pelvis at the widest part contacts the rear of the saddle.
This is the part to measure for your sit bone width when shopping for saddles.
Too narrow and it will cause perineum pressure. Too wide and it will cause chafing.
Your sit bones should fit comfortably in the saddle, with a little room to move around.
While in this position, you should not feel any pressure on your soft tissue.
You should not be sliding down the saddle due to tilt.
Leaning forward (60-0 deg)
As you lean forward in the saddle, your pubic bone rotates forward.
The saddle contacts the inner part of your pubic arch, where fit is much more sensitive.
Comfort is dependent on several factors.
Flexibility
A rider who is more flexible in their legs and back will be able to lean forward with less pelvic rotation.
This means more contact on their seat bones and less pressure on soft tissue compared to someone less flexible.
Stretching and increased mobility will improve your saddle comfort! But you shouldn't suffer until you get there.
Less flexible riders tend to remain on their seat bones when leaning forward.
Position
Some riders like to slide forward or back when they change positions.
Sliding forward while in the drops can reduce pelvic rotation and arm reach.
It shifts weight forward for faster cornering.
Whether you move around or not, the saddle shape needs to support you in the right places.
Shape
There are different saddle designs to account for how your body contacts the saddle as you ride.
A waved saddle shape is recommended for less flexible riders.
It raises the height of their seat bones to give more clearance in front. A perineum cutout helps here too.
As your pelvis rotates forward, your seat bones remain in contact with the rear of the saddle.
The steeper slope in back supports you from the rear, rather than holding you up from below.