Power to weight ratio is the single most important factor when climbing. Is how many watts you can produce divided by how much you weigh. The more watts you can sustain and the less you weigh, the faster you will be able go uphill.
A lot of bike races are won or lost when the road heads uphill and so power to weight ratio is a key calculation in the pro ranks, but the principle is also important if you want to improve your climbing ability, or you’re targeting a mountainous sportive with long climbs.
When climbing the major factor that stops us from riding quicker is gravity, so the more you weigh, the greater the effect of gravity and, therefore, the more difficult it is to get to the top of a climb. Therefore, when climbing, the lighter you are, the better, and, as with any aspect of cycling, the more power you can put out, the better.
With that in mind, power to weight ratio is simply a way of quantifying how much power you can put out in relation to how heavy you are. Power to weight is measured in w/kg and this gives a rough idea of your climbing ability.
For cyclists who are carrying around more than 10 extra pounds, losing weight and gaining power are equally achievable through good nutrition and focused training. Heavier cyclists have the potential to make bigger improvements because they can attack both parts of the equation.
Increasing the amount of power you put out will have benefits across all terrains, from the mountains to time trials to rolling roads, and possibly even on descents. The harder you can pedal, the faster you go.
Trying to lose weight can often impact negatively on your lean muscle mass and, subsequently, your power output. Dieting is also very stressful on your body and can seriously impact on your ability to recover from hard training sessions. In the long run this affects your overall training load and can result in a decrease in power. By dieting you may have lost weight but you may also have lost some precious watts.
Bradley Wiggins is famous for losing weight to increase his power to weight ratio and convert from a Olympic medalist on the track to the winner of the Tour de France. However, he did this after already maximising his power output. Most riders haven’t got to the point where they have maximised their power potential and, therefore, they can still make significant progress in that area. Wiggins was already at his physiological potential in terms of power output and therefore had no other choice than to reduce his weight in order to improve his power to weight ratio.
With the increased training load that it takes to improve your power output, chances are you will lose a little bit of weight naturally because you are simply training harder. That, of course, is as long as you are sensible with your food intake.