Single Speed Calculator
For freewheel bikes without shifters. Find the balance between acceleration and top speed.
Bike Setup
Common: 42, 44, 46, 48
Common: 16, 17, 18
The Art of the Single Speed
Riding single speed is about commitment. Without derailleur gears to bail you out, you need to choose one gear ratio that is "good enough" for everything—accelerating from lights, climbing moderate hills, and cruising on flats.
The Golden Target: 70 Gear Inches
For most paved city riding on flat-ish terrain, 70 Gear Inches is widely considered the perfect balance.
- 46t x 18t (on 700c x 25) ≈ 69 inches
- 42t x 16t (on 700c x 25) ≈ 69 inches
- 44t x 17t (on 700c x 25) ≈ 68 inches
Terrain Guidelines
Depending on where you ride, you should adjust your target:
- Hilly City / Loaded Commuting: Aim for 63 - 66 inches. You will spin out on downhills, but your knees will thank you on the way up.
- Flat City / Fast Group Rides: Aim for 72 - 76 inches. Harder to start, but flies once you are up to speed.
- SSCX / Gravel: Aim for 50 - 55 inches. Off-road surfaces add rolling resistance, and you need torque for mud and steep dirt climbs.
Spinning vs. Mashing
"Mashing" a big gear might feel fast, but it is exhausting and hard on your joints. "Spinning" a lighter gear is more aerobically taxing but sustainable. On a single speed, you have to do both.
If you are riding fixed gear (cannot coast), check out our Fixed Gear Calculator to ensure your ratio creates enough skid patches to save your tires.