Everybody knows losing weight can improve your cycling performance and make a big difference esp. in the hills where you have the most to gain by getting over them faster. But just how much off a difference? In the following examples lets compare two riders with a 30lb weight difference and see how that effects their performance when going up hills or inclines from 2% all the way up to 20% grade.
In a road race the hills often is where a racer has the most to gain on his opponents if he can go faster there, also in a TT you have the most to gain by getting up and over those hills as quick as possible so it doesn’t reduce your average speed/time as much. On the flats weight doesn’t matter as much but remember every slight incline you hit you might be going anaerobic while others are staying aerobic because they’re lighter. Rarely is a road truly flat, and it all starts to add up after a while, every little incline, esp. on the bigger steeper hills. Here’s a couple examples to highlight how much difference body weight can make in cycling in terms of power vs. weight and speed
Example 0% grade “flat” same speed
Well what about a slight incline of only 1% grade?
- 1 mile hill
- Incline 1%
Rider A
- 215lbs
- wattage 360w *Needs to put out 45watts more to match speed of Rider B
- Rate: 21.10MPH
Rider B
- 185lbs
- wattage 353w *Can put out far less wattage and easily keep up with Rider A with 45watts less
- Rate: 21.10MPH
Conclusion: because of slight increase in rolling resistance we see a small difference in wattages on perfectly level road, but not much.
Example 1% grade same speed
Well what about a slight incline of only 1% grade?
- 1 mile hill
- Incline 1%
Rider A
- 215lbs
- wattage 360w *Needs to put out 45watts more to match speed of Rider B
- Rate: 21.10MPH
Rider B
- 185lbs
- wattage 340w *Can put out far less wattage and easily keep up with Rider A with 45watts less
- Rate: 21.10MPH
Conclusion: Rider Since it’s almost flat you’d think that weight wouldn’t matter much, but guess again. A needs to put out 20watts more even with just a tiny incline of 1%, so even with a slight incline we already start to see that the heavier rider is starting to have to put out considerably more power, and most likely the bigger rider has a bigger cross section and more wind resistance too to make matters worse.
Example grade 2% same speed
Well what about a slight incline of only 2% grade?
- 1 mile hill
- Incline 2%
Rider A
- 215lbs
- wattage 360w *Needs to put out 45watts more to match speed of Rider B
- Rate: 18.31MPH
Rider B
- 185lbs
- wattage 331w *Can put out far less wattage and easily keep up with Rider A with 45watts less
- Rate: 18.31MPH
Conclusion: Rider A has to put out 29watts more. So we see there’s still a huge advantage to being lighter even on a slight incline that you’d run into all the time on roads most people would call “flat”. When riding in race or Time trial at or near your threshold, 30watts is considerable difference and could easily be the difference that pushes one the heavier rider into the red, or to be dropped.
Example 5% incline same speed
- 1 mile hill
- Incline 5%
Rider A
- 215lbs
- wattage 360w
- Time to top= 5.05
Rider B
- 185lbs
- wattage 319w *Can put out far less wattage and easily keep up with Rider A with 45watts less
- time to top =5.05
Conclusion: Rider B would have to put out 41watts less! But at 5% we see the full penalty of that extra weight is in effect, but beyond 5% the wattage difference DOES NOT increase incrementally. It peaks at about 5%. And 41watts id a big difference, it could mean the difference of saying mostly aerobic where the the heavier rider is in the red going anaerobic riding at his absolute threshold just to keep up.
Example 10% incline same speed
In this example we increase the incline to see what going from a 5% incline to a 10% incline does
- 1 mile hill
- Incline 10%
Rider A
- 215lbs
- wattage 358w *Needs to put out 45watts more to match speed of Rider B
- Rate: 6.75MPH
Rider B
- 185lbs
- wattage 314w *Can put out far less wattage and easily keep up with Rider A with 45watts less
- Rate: 6.75MPH
Conclusion: Rider A would have to put out 44watts more to keep up with Rider B. So you see even if we double the grade from 5% to 10% the difference in wattage to keep up doesn’t double but actually stays about the same.
Example 20% grade same speed
Well what about a slight incline of only 20% grade?
- 1 mile hill
- Incline 20%
Rider A
- 215lbs
- wattage 360w *Needs to put out 45watts more to match speed of Rider B
- Rate: 18.31MPH
Rider B
- 185lbs
- wattage 315w *Can put out far less wattage and easily keep up with Rider A with 45watts less
- Rate: 18.31MPH
Conclusion: Rider B again has to use 45watts less to go the same speed, so we see about a 1.5 watt per pound ratio of improvement.
Example 5% grade same power output
No let’s say both riders can put out the same wattage, then how much faster does the lighter rider get to the top on a easy 5% grade?
- 1 mile hill
- Incline 5%
Rider A
- 215lbs
- wattage 360w
- Rate: 11.87MPH
- Time to top= 46 seconds slower
Rider B
- 185lbs
- wattage 360w
- Rate: 13.08 MPH
- time to top = 46 seconds faster
Conclusion: Rider B gets to the top a whole 45 seconds faster traveling at 13.08 MPH vs. the heavier rider’s A speed of 11.87MPH, again a huge difference.
Example 10% grade Same Power
- 1 mile hill
- Incline 10%
Rider A
- 215lbs
- wattage 360w *Needs to put out 45watts more to match speed of Rider B
- Rate: 6.79MPH
Rider B
- 185lbs
- wattage 360w *Can put out far less wattage and easily keep up with Rider A with 45watts less
- Rate: 7.70MPH
- Time: +1:36
Conclusion: If both riders put out the same wattage on a 10% 1 mile hill, the lighter rider would get to the top of the climb a hole minute and half faster then the other heavier rider that weighs 30lbs more. And you see the difference between the previous example of 5% grade vs. 10% in this example shows that as the hill gets steeper the lighter rider gets to the top even faster yet.
Example 20% Same Power
Well what about a slight incline of only 20% grade?
- 1 mile hill
- Incline 20%
Rider A
- 215lbs
- wattage 360w *Needs to put out 45watts more to match speed of Rider B
- Rate: 3.53MPH
- Time: 17:38
Rider B
- 185lbs
- wattage 360w *Can put out far less wattage and easily keep up with Rider A with 45watts less
- Rate: 4.04MPH
- Time: 15:25 = +2:13 faster, two minutes and 13 seconds faster
Conclusion: If you’re paying close attention you’ll notice that the steeper it gets the longer everybody has to spend working up that hill, and the steeper and slower the going, the more even a slight improvement in weight to power performance makes in getting to the top minutes faster, not just seconds!
Final Conclusion:
- As expected the heavy rider has to put out significantly more power to go the same speed as the lighter rider. There’s a lot to gain from being as light but powerful as possible, the lighter rider without even adding more fitness just losing weight is much more efficient and faster all around.
- Even the slightest of inclines forces the heavier rider to work significantly harder, only when the road is perfectly flat is there little difference but the real world most flat roads have plenty of slight grades. Imagine two riders near their FTP their functional threshold and every time there was even a slight incline the the heavier rider would go anaerobic because the run turns up slightly for a short distance, but this happens over and over again. Where the lighter rider might be able to stay aerobic even over slight inclines because of less weight penalty.
- You would think at first that the steeper the hill the greater the weight penalty, but it appears that the weight penalty ramps up quickly from 0-5% grades then after 5% it really doesn’t go up anymore as the hill gets steeper, so in our example everything after 5% grade is about a 45watt difference.
- Another thing to take note of is how as the grade gets steeper the lighter rides gains more and more of a time advantage? But at the same time the difference between their speeds gets smaller, as 20% grade with both riders putting out the same power the lighter rider gets to the top over 2 minutes faster! This is because it’s such a slow steep hill that both riders are spending more time then ever getting over it vs an easier hill they’d get over much faster, so during that time the lighter rider’s half mile per hour faster speed really adds up in the end. Keep in mind both riders are going very slow but the difference between speeds is significant in relation of percentage to each other, so 0.5mph per hour difference normally isn’t much, but when you’re both going 3-4mph it’s around a 12%. It’s like the difference between 20mph and 22 mph on the flats which as you know is a big difference esp. for long distances.
- If you’re a heavier rider, try to get a slight lead before a big climb
- Don’t give up think the light guys are having to work less and less compared to you as it gets steeper, after 5% grade there’s not difference between that and 30% grade
- Keep in mind that drafting vs. not drafting can be about 30% difference in power out put, the last thing you want to do is be out in the wind then grinding up inclines while the light guys draft behind you up the inclines, make them work, or get behind them on the slight inclines to even the tables, on steeper grades where you slow way down and there’s not as much wind resistance it doesn’t do much to help you having them in front of you. So for example on rolling terrain you could let the light riders pull and draft up the hill, after it flattens out or declines it’s your turn to hammer, the best time to break away form them would be right as the hill levels out, break away