Sachs MadAss 50 vs Yamaha Y15ZR ergonomics

Rider fit: reaching the ground

The Sachs MadAss 50 has a 835 mm seat; the Yamaha Y15ZR sits at 845 mm — a 10 mm difference. As a rule of thumb you flat-foot a bike when your inseam roughly matches its seat height: about 84 cm for the Sachs MadAss 50 and 85 cm for the Yamaha Y15ZR.

That makes the Sachs MadAss 50 the easier reach to the ground — the safer pick for shorter riders or anyone who wants both feet planted at a stop — while the Yamaha Y15ZR gives taller riders more legroom and a more open knee bend. Load your own height and inseam into the simulator to see exactly how each one fits you.