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Total Climbing Weight: Reduction in Ascent Time For Steep Climbs
For extreme climbing as in the Everest Challenge, every extra pound of weight translates directly into increased ascending time. Any means of reducing total riding weight can make a large difference.
Steep climb savings
On a steep climb, most energy goes into higher kinetic potential: the energy you expend moves you and your bike up the hill. Friction from wind, tires and mechanical drag is at a minimum; it’s mostly about the grade. Thus, how fast one one ascends is all a power-to-weight issue, very different than on the flats, where it’s a pure power issue, with all the energy going into friction (air resistance mainly).
Example
Air resistance is minimal for a steep climb, because speeds are very low. Therefore, there is a near-linear relationship between weight and rate of ascent (there are mechanical losses and some friction from tires, air, etc, but these losses are relatively small).
For the example, let’s assume a rider equipped as follows:
Rider: 176 pounds
Clothing and shoes: 4 pounds
Bike: 15 pounds
Water: 4 pounds
Helmet: 1 pound
TOTAL: 200 pounds
For this configuration, a 1% reduction in total weight means that 2 pounds must be dropped. It should result in nearly a 1% reduction in ascent time, assuming a steep ascent and quality gear.
Taking the Everest Challenge as an example, let’s assume 10 hours of climbing over 2 days out of a 14 hour race (there are somewhat flat intermediate sections after all).
10 hours = 36,000 seconds (3600 seconds per hour X 10)
1% savings = 360 seconds = 6 minutes
While 6 minutes might not seem like a lot for a 10-hour climb, it is common to see leading competitors clustered within a few minutes of each other. In other words, saving 2 pounds might mean 1st place or 5th place!
But what if the rider can drop 5 pounds of body fat, and 5 pounds of equipment weight by using a lighter bike, wheels, shoes, etc? That’s 10 pounds, and it means a full half hour saved. A half hour could mean 10 or 20 places! In short, weight does matter a great deal.
| Total Weight (pounds) |
Weight Reduction (pounds, %) |
Potential Time Reduction (minutes:seconds) |
Comments |
|---|---|---|---|
| 200 | 0, 0% | 00:00 | |
| 198 | 2, 1% | 06:00 | Difference between light wheels and average ones |
| 196 | 4, 2% | 12:00 | Difference between average bike and light one |
| 194 | 6, 3% | 18:00 | |
| 192 | 8, 4% | 24:00 | |
| 190 | 10, 5% | 30:00 | |
| 184 | 16, 8% | 48:00 |
Other benefits of reduced weight
One can argue that reductions in weight do not result in linear reductions in ascent time, since there are friction and mechanical losses. This is certainly true.
But there are other key benefits:
- Reduced weight is a psychological boon because ascending just feels easier.
- Reduced total weight means increased comfort for the entire body.
- Reduced weight means a higher cadence, which reduces premature muscle fatigue on steep grinding climbs.
- Reduced weight increases the amount of time that the rider can stay aerobic on steep climbs, thus preserving precious glycogen, and perhaps reducing fluid loss; there is a wider band of exertion which is possible.
These benefits might well mean that the gains from reducing weight could actually be greater than computed here, at least when the reduction is more significant.
