CORRECT SIZING
The right saddle width isn't a guess, it's a measurement. Getting it right is the single most important step toward a completely pain-free ride. This guide walks you through measurement and model selection in three simple steps.
Measure Your Sit Bone Width
Your sit bones (ischial tuberosities) are the two bony points that carry your weight when seated. Your saddle must be wide enough to fully support both and Zeta's Reactive Padding™ handles the rest once you're correctly sized.
Sit bone width + 30–40mm = correct saddle size
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Sit on a Hard Surface Sit naturally on a wooden chair or firm step — the way you'd normally sit at a dining table.
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Locate Your Sit Bones Use your fingertips to feel the two bony pressure points beneath you, then slide a coin directly under each one.
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Stand Up & Measure Rise from the seat and measure center-to-center between the two coins. That distance is your sit bone width.
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Add 30–40mm Add 30–40mm to your sit bone width and select the closest larger saddle size available.
The Coin Method in Action
Place two coins on a hard surface, sit naturally, then slide each coin to rest directly beneath each sit bone. Stand up and measure coin center to coin center — this is your sit bone width. In this example, the measurement reads approximately 110mm.
Sit bone width of 110mm + 30–40mm = target saddle width of 140–150mm → choose the Optima Ti 145mm or Optima Ti 155mm.
Match Your Measurement to a Saddle Width
Use this quick-reference table to translate your sit bone measurement into the correct Zeta saddle width.
| Sit Bone Width | Add 30–40mm | Target Width | Recommended Zeta Models |
|---|---|---|---|
| Under 100mm | +30–40mm | 130mm | Modus 130mm |
| 100–115mm | +30–40mm | 130–145mm | Modus 130mm, Optima Ti 145mm, Ultima 145mm |
| 115–125mm | +30–40mm | 145–155mm |
Optima Ti 145mm · Optima S 145mm · Optima Ti 155mm · Ultima 145mm · Ultima 155mm |
| 125–135mm | +30–40mm | 155–165mm | Optima Ti 155mm · Ultima 155mm · Ultima 165mm |
| 135mm and above | +30–40mm | 165mm+ | Ultima 165mm |
Choose the Right Model for Your Riding Style
Width gets you on the right saddle. Riding style gets you on the best saddle. Once you know your size, use this guide to pick the ideal model.
Road & Performance
Aggressive forward position · clipless pedals · rides 1+ hourPerformance geometry with Reactive Padding™ exactly where you need it. The carbon rail version saves weight for riders who demand all-day comfort without sacrificing speed.
Gravel & Endurance
Mixed terrain · variable position · long days in the saddleThe wider platform accommodates the more upright gravel position, with outstanding vibration absorption for whatever rough roads send through the frame.
Mountain Biking
Technical terrain · dynamic position · frequent standingDesigned for riders who move around the saddle constantly. The profile supports seated climbing and the off-the-back descending position without sacrificing stability.
Casual, Hybrid & Recreational
Upright position · leisure rides · e-bikes · commutingAn upright riding position shifts more weight onto the sit bones. The Ultima's wider platform distributes that load across longer rides without any pressure point build-up.
Spin & Indoor Cycling
Studio bikes · Peloton · Zwift · indoor trainersPurpose-built to fit the universal rail adapters on most indoor bikes. Same patented Reactive Padding™, engineered for the fixed-position demands of indoor riding.
Performance & Weight-Conscious
Racing · fast group rides · maximum stiffness-to-weight ratioCarbon rails and a performance-tuned profile for riders who prioritize power transfer and weight savings. Best suited to narrower sit bones and an aggressive position.
Still Not Sure? Try it Risk-Free.
Order the saddle that matches your measurement and ride it for a full 30 days. If it doesn't eliminate your pain, return it for a full refund — no questions asked. Or reach out directly and Dr. Patrick O'Shea will personally help you choose the right fit before you order.