Reactive Padding™ Test Results
Nine saddles. One rider. One session.
A Zeta model recorded the lowest peak pressure in each of the two zones measured — and no conventional saddle was lower in both.
In April 2024 nine saddles were measured on a gebioMized pressure mat by an engineer and a professional bike fitter. Same rider, same road bike, same fit routine for every saddle. Every saddle bare — no covers, no shims.
The mat reports peak pressure in two places that matter: the perineal zone between the sit bones, and the sit bones themselves. A saddle can lower one by raising the other. The interesting question is what a saddle does to both.
Lowest peak perineal pressure — Ultima
24% below the lowest conventional saddle in the test (Selle Italia Carbonia SLR, 589 mbar). Optima took second place at 499.
Lowest peak sit-bone pressure — Modus
9% below the lowest conventional saddle in the test (Specialized Power Mimic, 909 mbar).
Conventional saddles lower in both zones
Across all nine runs, no conventional saddle recorded lower pressure than a Zeta model in both the perineal and the sit-bone zone. Where one was lower in a zone it was markedly higher in the other — by 163 to 267 mbar in one case, by 254 to 473 mbar in the other.
Nose angle moved Modus by 104 mbar
Dropping the nose from −0.9° to −1.5° lowered peak sit-bone pressure from 934 to 830 on the same saddle, same rider, same session. Setup is not a detail.
That trade-off shows up cleanly in the conventional saddles. The one with the lowest perineal pressure recorded the third-highest sit-bone pressure. The one with the lowest sit-bone pressure recorded the third-highest perineal pressure. Relief in one zone came from load moving to the other. The table below is sorted so you can check it yourself.
| Saddle | Perineal | Sit bone L | Sit bone R | Sit bone peak |
|---|---|---|---|---|
| Zeta Ultima | 447 | 915 | 961 | 961 |
| Zeta Optima | 499 | 753 | 988 | 988 |
| Selle Italia Carbonia SLR | 589 | 785 | 1097 | 1097 |
| Zeta Modus · −0.9° | 666 | 795 | 934 | 934 |
| Zeta Modus · −1.5° | 678 | 667 | 830 | 830 |
| Specialized Mirror | 703 | 726 | 1084 | 1084 |
| Specialized Power Mimic | 920 | 909 | 879 | 909 |
| Selle Italia Boost | 922 | 916 | 1435 | 1435 |
| Selle SMP | 1194 | 724 | 1252 | 1252 |
All figures are peak pressure in millibar, 12 mm chamois condition. Sorted by perineal pressure, lowest first.
How the test was run
- gebioMized pressure mapping, 3 April 2024, one continuous session.
- One rider throughout. One road bike. The fitter set each saddle's position for that saddle rather than copying one position across all of them.
- Every saddle measured bare. No seat covers, no aftermarket padding.
- Every saddle was run twice — once in a 3 mm chamois and once in a 12 mm chamois. All nine measured lower with the thicker chamois, so the two conditions rank saddles the same way. The figures above are the 12 mm condition; mixing the two would not be valid.
- Where left and right sit-bone readings differ, the table reports the higher of the two. Several saddles are markedly asymmetric and taking the worse side is the conservative choice.
- Two nose angles were recorded for the Modus and both are published. The other saddles have a single recorded run each.
- This was the second of two pressure-mapping sessions run by the same engineer. The first produced results consistent in direction with these. That session included saddles whose data we are not free to publish, so this page reports the April 2024 session on its own.
Who ran it, and who paid for it
The session was conducted by Eugene Bernosky, engineer, and Justin Lucke, professional bike fitter. Neither holds any financial interest in Zeta Saddles. Neither was given direction on protocol, saddle selection, or how results were reported.
Mr Bernosky approached Zeta to propose the test and was not paid for it. Zeta paid Mr Lucke's standard session fee.
We state that plainly because a brand paying for its own testing is ordinary, and not saying so is not.