Short answer: measure the distance between your sit bones, then choose a saddle whose stated range includes that number. For most riders the saddle ends up 20 to 25mm wider than the measurement, but do not calculate it yourself, because manufacturers publish actual ranges and those differ between models of identical width. A wider or softer saddle is not a more comfortable one.
Contents
- Why width is the number that matters
- Measuring your sit bones at home
- Real sit bone ranges
- Decoding S1, S3, L1 and L3
- Cutouts and channels
- Why more padding is usually worse
- Your riding position changes the answer
- Frequently asked questions
Why width is the number that matters
Your weight should rest on your ischial tuberosities, the two bony points at the base of the pelvis, universally called sit bones. Bone tolerates pressure. The soft tissue between and in front of those bones does not, and that tissue contains the nerves and blood vessels responsible for every numbness complaint in cycling.
A saddle that is too narrow leaves the sit bones hanging off the edges, so your weight transfers forward and inward onto soft tissue. A saddle that is too wide causes chafing at the thighs and can stop you rotating your pelvis forward properly.
Sit bone spacing varies far more between people than most riders assume, and it does not track height, weight or gender reliably. This is why saddle choice cannot be guessed.
Measuring your sit bones at home
Ten minutes with things you already own.
- Find a piece of corrugated cardboard, or a few layers of kitchen foil over a folded towel.
- Put it on a hard flat chair or a step. Not a cushioned seat.
- Sit down with your full weight, feet flat, and lean forward slightly to imitate your riding posture rather than sitting upright.
- Lift your feet briefly so all your weight goes through the sit bones, and rock gently.
- Stand up. You will see two clear depressions.
- Measure from the centre of one depression to the centre of the other, in millimetres.
Typical adult measurements land between 100mm and 150mm. Measure twice, and if the two readings differ take the larger.
We can also do this in the store in a couple of minutes with a proper measuring device, which is more accurate than cardboard and costs nothing.
Real sit bone ranges
The usual advice is to add 20 to 25mm to your measurement. That is a reasonable starting point and it is not how manufacturers actually specify their saddles. Selle SMP publishes a sit bone range for every model, and comparing them shows why the arithmetic rule is unreliable.
| Saddle | Saddle width | Stated sit bone range |
|---|---|---|
| SMP Blaster | 131mm | 90 to 115mm |
| SMP VT20C | 144mm | 90 to 125mm |
| SMP Dynamic | 138mm | 116 to 150mm |
| SMP Nymber | 139mm | 116 to 150mm |
| SMP F30 Carbon | 150mm | 121 to 150mm |
| SMP VT30C | 155mm | 126 to 150mm |
| WTB Gravelier Medium | 140mm | 110 to 125mm |
Look at the VT20C and the Dynamic. The VT20C is 6mm wider yet suits narrower sit bones, because the shape of the rear section and where the width sits matter as much as the maximum dimension. This is the reason to use the manufacturer's stated range rather than adding 22mm to your own measurement and shopping by width alone.
The full selection is in saddles.
Decoding S1, S3, L1 and L3
Selle Italia labels every saddle with a letter and a number, and almost nobody knows what they mean. The system is genuinely logical once explained.
The letter is width.
- S, for sit bone spacing below 120mm
- L, for sit bone spacing above 120mm
The number is the cutout, and it is chosen by your flexibility rather than your size.
| Number | Cutout | Suits |
|---|---|---|
| 1 | None, closed saddle | Limited pelvic rotation, more upright riders |
| 2 | Flow, smaller opening | Moderate flexibility |
| 3 | Superflow, larger opening | Good pelvic rotation, aggressive positions |
So an SLR Boost in L3 is a wide saddle with the large cutout, and an S3 is the narrow version of the same thing.
The rule that matters most: a stiff rider can use size 1, 2 or 3, but a flexible rider should not use a saddle without a cutout. The more you rotate your pelvis forward, the more your weight moves onto soft tissue, and the more you need the relief channel.
Cutouts and channels
A cutout removes material from the centre of the saddle, and a channel is a recessed groove doing the same job with less material removed.
Both exist to reduce pressure on the perineal area, and the evidence for their benefit is strong enough that most performance saddles now have one. If you experience numbness on rides over an hour, this is the first feature to look for, ahead of padding or width changes.
The trade-off is that a cutout concentrates your weight on the two remaining pads, so an incorrectly sized saddle with a cutout can feel worse than a correctly sized one without. Get the width right first.
Why more padding is usually worse
This is the most common and most expensive misconception in saddle buying.
A heavily padded saddle feels excellent for the first ten minutes. Under sustained load the padding compresses beneath your sit bones and is displaced upward into the space between them, pushing directly into the soft tissue you were trying to protect. The more padding, the more pronounced this becomes.
A firm saddle of the correct width supports the sit bones and leaves the tissue between them unloaded. This is why experienced riders on 200km rides use saddles that feel unforgiving in a showroom.
Padding is worth having for upright riding where you sit heavily on the saddle, short commutes, and touring on a leather saddle that moulds over time. It is not the answer to pain on a road bike.
Your riding position changes the answer
The same rider needs different saddles on different bikes, because pelvic rotation changes which part of you carries the weight.
| Position | Weight sits on | Saddle wanted |
|---|---|---|
| Upright, hybrid or city | Sit bones fully | Wider, some padding |
| Moderate, endurance road or gravel | Sit bones, pelvis partly rotated | Mid width, channel or cutout |
| Aggressive, race or aero | Forward, onto the nose area | Narrower, firm, generous cutout |
| Triathlon or time trial | Rotated fully forward | Short, wide nose, deep relief channel |
If you have changed your position recently, by dropping the bars or fitting a shorter stem, your existing saddle may have stopped working through no fault of its own. Our guide to the signs your position is wrong covers the interaction, and seatpost setback affects it too.
Frequently asked questions
Do women need a women's specific saddle?
Not automatically, and the labelling is less meaningful than the measurement. Women do on average have wider sit bone spacing than men, which is why women's models tend to be wider and often carry a larger cutout, but the overlap between individuals is enormous. Plenty of women fit a saddle marketed as unisex and plenty of men need a wide one. Measure your sit bones and choose by the stated range and by cutout, treating the gender label as a hint about the likely shape rather than a rule.
How long does it take to get used to a new saddle?
Two to four weeks of regular riding for the tissue to adapt, and it is worth distinguishing adaptation from a wrong saddle. General soreness that reduces week by week is normal, particularly if you are returning after a break. What is not normal and will not improve is numbness, sharp localised pain, pain on only one side, or chafing at a specific point. Those indicate the wrong width, wrong shape or wrong tilt, and more riding makes them worse rather than better.
Do saddles wear out?
Yes, and it happens gradually enough that people blame themselves rather than the saddle. Foam padding compresses permanently over thousands of kilometres, the shell can develop flex or crack, and rails can bend after a crash. In Indian conditions sweat and monsoon water accelerate the breakdown of foam and the bond between cover and shell. A saddle that was comfortable for two years and is now not may simply be finished. Check for a saddle that feels softer on one side or sits visibly asymmetric.
Can I use the same saddle model on my road bike and my mountain bike?
You can, but the same model is often not the right choice for both, because your position differs. On an upright mountain or hybrid position your pelvis rotates less and your weight sits further back on the sit bones, which usually wants a slightly wider saddle. On a road bike in a lower position you rotate forward and need more relief at the front. Many riders happily run the same saddle on both and simply accept a compromise on one. If one bike is uncomfortable and the other is not, position is the reason.
Should I buy a saddle online or try one first?
Try first if you possibly can, because saddles are the one component where measurement narrows the field but does not decide it. Two saddles of identical width and cutout can feel entirely different because of the curvature across the top and along the length, and there is no specification for how that will suit your anatomy. Come to our Kondapur store, have your sit bones measured, and sit on a few. If you are ordering remotely, send us your measurement and your riding position and we will narrow it to two or three sensible options.
Get measured
Sit bone measurement takes two minutes at our Kondapur store and costs nothing. If you cannot get to us, measure at home using the cardboard method above and give the number to ask TBA Guide, along with what you ride and where it hurts, and we will tell you which saddles are worth considering.
