sport / default rider 183 cm
Aprilia RS 660 vs Aprilia RS4 125 ergonomics
Aprilia RS 660 and Aprilia RS4 125 have modeled posture scores within three points for the 183 cm default rider. Treat this as a planning estimate; posture preference, data confidence, and a real test sit still matter.
Modeled fit comparison
Aprilia RS 660
All contacts reached
Aprilia RS4 125
All contacts reached
The modeled scores are within three points, so the result does not distinguish a higher-scoring bike. Treat the result as a planning estimate and compare each bike's geometry confidence before a real test sit.
Rider fit: reaching the ground
The Aprilia RS 660 lists a 820 mm seat; the Aprilia RS4 125 lists 820 mm, within a few millimetres of each other. Seat height is only a first-pass ground-reach input. It does not establish safety or actual foot contact. Seat width, suspension sag, boots, mobility, load, and individual proportions can materially change the result.
Geometry snapshot
| Spec | Aprilia RS 660 | Aprilia RS4 125 |
|---|---|---|
| Seat height | 820 mm | 820 mm |
| Wheelbase | 1,370 mm | 1,353 mm |
| Wet weight | 183 kg | 144 kg |
| Displacement | 659 cc | 124 cc |
Posture metrics
Knee angle
- Aprilia RS 660
- Sport (65.5 deg)
- Aprilia RS4 125
- Sport (60.7 deg)
Hip angle
- Aprilia RS 660
- Neutral (106.6 deg)
- Aprilia RS4 125
- Neutral (99.6 deg)
Elbow angle
- Aprilia RS 660
- Relaxed (143.3 deg)
- Aprilia RS4 125
- Relaxed (143.3 deg)
Torso lean
- Aprilia RS 660
- Forward (29.1 deg)
- Aprilia RS4 125
- Forward (25.2 deg)