- Issue Time
This formula is: VAM = (Difference in Vertical Altitude x 60) / Time
In the days before power meters were commonplace, riders often used VAM to measure their climbing ability. VAM started out as an acronym for velocità ascensionale media (average rate of climb) in Italian, but over time VAM became known in English as vertical rate of climb in meters. i.e. VAM is a number that shows how many meters you climb vertically per hour.
This is a simple and pure way to measure your climb speed very directly.
No matter what kind of road conditions you are on, winding or even climbing, VAM can directly reflect your climbing level and show your ability to resist gravity. The higher the number, the better.
All computers with GPS function can measure your VAM while riding, but not all data analysis websites and apps support the display. If you don't have these devices at all, you can time the distance or stage you pass, check the altitude gain of the starting and ending points on the computer, and perform some simple mathematical operations to get the VAM. This formula is:
VAM = (Difference in Vertical Altitude x 60) / Time
Although VAM can simply measure your climbing ability, there are also some load types. The same person may change according to the slope of the stage. For example, rushing to a 20% slope in a short time VAM is much higher than a 6% slope.
So the steeper the slope, the higher the VAM, but super steep slopes are all short. According to the training data, VAM increases exponentially with the change of slope at constant power. For example, a 64kg driver with an average output of 300W has a VAM value of 1180 at 5% incline, 1290 at 8%, and 1475 meters at 11%, an increase of 110 from 5% to 8%. An increase of 185 from 8% to 11%. The data is presented with a formula with slope variation to express VAMw/kg, which can normalize the values for different slopes.