What VAM means
VAM comes from the Italian velocità ascensionale media, the average climbing speed. It is the vertical distance climbed in one hour, in meters per hour:
VAM = elevation gain (m) ÷ climbing time (hours)
Unlike speed on the road, VAM can be compared between climbs of different gradients, which is why cycling fans and coaches use it to judge climbing performances.
From VAM to watts per kilo
On a steep climb most of a rider’s power goes into lifting body and bike, so VAM is closely linked to power per kilo. Italian sports doctor Michele Ferrari popularized this rule of thumb:
W/kg ≈ VAM ÷ (200 + 10 × gradient in %)
Multiplying by the rider’s weight gives an estimate of power in watts. The rule assumes typical bike weight, rolling resistance and little wind. It is most reliable on climbs of 7% or more, where air drag matters less; on gentle slopes, drafting and wind can make it far off.
Benchmarks
| VAM | Level |
|---|---|
| under 800 m/h | recreational pace |
| 800 to 1,200 m/h | fit club cyclist |
| 1,200 to 1,700 m/h | strong amateur racer to professional |
| around 1,700 m/h or more | Grand Tour leaders on long climbs |
These figures depend on the length of the climb: a short effort of 5 minutes allows a far higher VAM than a 40-minute climb.
Example
A rider who climbs 600 m in 45 minutes on an average gradient of 7% has a VAM of 600 ÷ 0.75 = 800 m/h. The estimate is 800 ÷ (200 + 70) = about 3.0 W/kg, or about 222 W for a 75 kg rider. A climb at 8% ridden at 1,650 m/h corresponds to about 5.9 W/kg.
Getting good numbers
- Use the elevation gain and time of a segment from your GPS or a climb profile, not the whole ride.
- Barometric altimeters are more accurate than GPS altitude.
- A power meter gives your real power; compare it with the estimate to see how wind or drafting affected it.
- To improve VAM, raise your power at threshold or lose weight, ideally fat rather than muscle.