If you want to buy a new bike saddle, the right size is crucial – especially for longer rides. An uncomfortable saddle leads to pain, numbness, and pressure points. The good news: you can determine your saddle size at home in five minutes. You only need corrugated cardboard, a ruler, and a hard chair.
Why the right saddle size is so important
Your pelvis has two bony protrusions at the bottom – the sit bones. These are exactly what should rest on the bike saddle and support your weight. If the saddle is too narrow, your sit bones slide off to the sides and the weight lands on sensitive soft tissue. If it’s too wide, your inner thighs rub with every pedal stroke.
The distance between your sit bones is individual. For men, it typically ranges from 10 to 14 cm, for women from 11 to 16 cm. A saddle that fits your neighbor perfectly can be a source of pain for you.
Measuring sit bone width – at home in 5 minutes
You don’t need a bike fitting or an appointment. With corrugated cardboard and a ruler, you can measure your sit bone width yourself.
Step 1: Prepare materials
You need a piece of corrugated cardboard (about 30 by 30 cm, for example from a box), a hard chair or stair step, a ruler or tape measure, and a pen.
Step 2: Sit on the cardboard
Place the cardboard on a hard surface. Sit on it in a normal posture, feet flat on the floor. Lean slightly forward, about as you would on a bike – this shifts the pressure to where it lies when cycling.
Step 3: Sit still for 30 seconds
Stay still for 30 seconds. Don’t wiggle, or the impressions will become blurry. Tip: If you place a book under each foot so that your knees are slightly higher than your hips, it increases the pressure on your sit bones and makes the impressions clearer.
Step 4: Measure the impressions
Stand up and look at the cardboard. You will see two clear impressions – these are your sit bones. Measure the distance from the center of the left impression to the center of the right. This is your sit bone width.
Step 5: Derive saddle width
Add a margin to the measured value depending on your sitting position. Upright (city, e-bike): plus 3 cm. Sporty-moderate (trekking, MTB): plus 2 cm. Road bike: plus 1.5 cm. For a 12 cm sit bone width and sporty posture, this results in a 14 cm saddle width, i.e., 140 mm.