Start with inseam
Multiply inseam by 0.65 for an indicative frame size in centimetres. An 82 cm inseam gives about 53 cm. Compact, step-through and electric frames may use different labels.
Step-through or diamond frame
A step-through frame makes frequent stops easier, especially with work clothes, luggage or a child seat. Its low tube reduces standover concerns, but cockpit length and handling still matter.
| Use | Priority | Check |
|---|---|---|
| Short trips | Ease | Mounting and stopping |
| Daily commute | Long-term comfort | Reach, bar adjustment |
| Loaded bike | Stability | Wheelbase and brakes |
| Electric bike | Weight control | Standover and low-speed balance |
Geometry and adjustments
Reach to the handlebar
You should reach the grips without locking the elbows or rounding the back excessively. An adjustable stem refines a good size but cannot rescue a frame that is far too long.
Saddle height
The knee should remain slightly bent at the bottom of the pedal stroke. You normally step slightly off the saddle when stopping rather than keeping both feet flat while seated.
Control with luggage
Test the bike with the bags, rack or child seat you plan to use. Added weight changes balance at low speed.
Between two sizes
For urban use, the smaller candidate is often easier to manoeuvre and mount. Choose the larger one only if the handlebar remains within easy reach and the saddle lowers sufficiently.