Training & Nutrition - Does type of bike impact calories/hr?

Been riding a hybrid for exercise but recently started shopping for a road bike so I can keep up with friends on faster road bike during casual rides - not interested in racing. Stopped by LBS in my shopping and the guy tells me that the road bike is better exercise because it is more efficient. I know it is more efficient in terms of speed and milage but that is not my objective during exercise.
From a calories per hour or general biking exercise standpoint, would the type of bike make any difference? I have been assuming that my calories per hour and general exercise benefits would be equal no matter what type of bike I am riding. One hour on a hybrid = one hour on a road bike.
Any evidence to the contrary?

nope, given the same exertion, of course cals/hr = cals/hr

cals/mile are obviously greater on the hybrid than the road bike

The bike that will keep you looking forward to the next ride is the ideal bike. Don't worry about the calories per hour. Look for the bike that will give you the most hours per ride.

If you want to burn more calories/hr just ride faster. Doesn't matter what kind of bike really...

Road bike riding is far superior to a hybrid trying to do road riding. Its not about the calories, but its about riding enjoyment. The ability to go faster and climb better makes a rider want to ride more.

Its like getting into shape. When you're out of shape, everything is difficult to do. But once in shape, your body gets used to the stress and soon the muscles, cardio vascular, pulmonary systems just function better.

Road bike is more efficient so you have to ride faster than you would on a hybrid with knobby tires in the snow, uphill, on a windy day. Calories burned is about exertion. Ride whatever bike you want.

What a bunch of bunk! I'd love to hear the LBS guy try to explain that one.

The only way a bike will increase your cal/hr is if you are more comfortable on it and can therefore exert more energy.... but efficiency? I can't imagine.

He's speaking sales BS. More efficient = less energy spent = less exercise. If you can keep up with your friends while still riding the hybrid, that would be the best exercise, but might not be realistic. Getting a bike that matches theirs would be a lot more enjoyable, and I think it's important to enjoy your exercise.

In many cases, you could burn more on the hybrid - but only because it's harder to get going, and harder to get up hills. I've given up on high-intensity workouts on my roadbike (in the city) because I can't maintain high-speeds safely. Of course, I guess I could let the air out of my tires and wear a big back pack.

Been riding a hybrid for exercise but recently started shopping for a road bike so I can keep up with friends on faster road bike during casual rides - not interested in racing.

Well, seems you have 'qualified' your Q even before asking it...
Independent of calories/hr, keeping up with your friends dependz. If you're a 'stronger' rider then pick a tool that'll make you work harder. Less hardy than them, then stack as much in your favor as possible.
Now, on to the Q.


Stopped by LBS in my shopping and the guy tells me that the road bike is better exercise because it is more efficient. I know it is more efficient in terms of speed and milage but that is not my objective during exercise.
From a calories per hour or general biking exercise standpoint, would the type of bike make any difference? I have been assuming that my calories per hour and general exercise benefits would be equal no matter what type of bike I am riding. One hour on a hybrid = one hour on a road bike.
Any evidence to the contrary?

Speed, mileage are really part of the same measure. But neither indicate 'load'; unless qualified in a number of other ways. So many other variables.
The Kcalories you expend is directly tied to the 'power' you put out, and therfore the 'work'. That can be the same for many different bikes and other 'exercises'. The more 'work' you do, the greater the Kcals expended.
Back to bikes. Assuming the same rider, a similar 'fit' for the rider, assuming similar mechanical efficiencies for the machines (and a decent hybrid will be roughly the same as a decent traditional road bike), assuming using the same gearing and riding methods, that leaves one important variable, aerodynamics.
AT any given 'speed' a more upright position will require more work to overcome air resistence. So, a more upright position, as with riding many hybrids, ridden at the same speed as a more aero position on a 'road' bike, will require more 'work'.
The 'hour on a hybrid' V 'hour on a roadie' is a red herring.
work is work. "American Idol" may allow you to get around that, but physics and biomechanics will not.

I always thought that calories per mile were almost the same across riders, bike style and speed of ride. This seems to be a more useful measure than calories per hour.

BTW, the figure I see most often is 40 calories per mile.

I always thought that calories per mile were almost the same across riders, bike style and speed of ride. This seems to be a more useful measure than calories per hour.

BTW, the figure I see most often is 40 calories per mile.

No of course not. Go ahead and ride a mile downhill coasting most of the way. Then ride a mile up Alpe du Huez at 16mph. Then ride a mile on the flats at 25mph. Ride a MTB with fat knobbies at 25 mph in the flats. See what I mean? It is about exertion. Your body has no concept of miles. It is about exertion for a specific duration.

No of course not. Go ahead and ride a mile downhill coasting most of the way. Then ride a mile up Alpe du Huez at 16mph. Then ride a mile on the flats at 25mph. Ride a MTB with fat knobbies at 25 mph in the flats. See what I mean? It is about exertion. Your body has no concept of miles. It is about exertion for a specific duration.
Hills would be the major exception to this 40cal/mile rule of thumb, since you are liing weight against gravity. But speaking physically, it takes roughly the same amount of work to push a given weight on the flats for one mile, regardless of the speed.

There is slightly more rolling resistance from a MTB's fat tires. A MTB weighs more, so that must be taken into account. There is also a little more wind resistance on an MTB because a road bike is more aerodynamic.

If you're going 25 mph, compared to 10 mph, you are burning more calories per minute, but each mile will take less time, so the number of calories per mile will almost even out.

Hills would be the major exception to this 40cal/mile rule of thumb, since you are liing weight against gravity. But speaking physically, it takes roughly the same amount of work to push a given weight on the flats for one mile, regardless of the speed.

There is slightly more rolling resistance from a MTB's fat tires. A MTB weighs more, so that must be taken into account. There is also a little more wind resistance on an MTB because a road bike is more aerodynamic.

If you're going 25 mph, compared to 10 mph, you are burning more calories per minute, but each mile will take less time, so the number of calories per mile will almost even out.Depends upon how fast you're going. The calories/mile only stays linear at low-speeds of 15mph or less, which most people ride at anyway. But it's a misconception that it interpolates linearly to higher speeds:

AnalyticCycling (http://www.analyticcycling.com/ForcesPower_Page.html)
http://www.analyticcycling.com/ForcesPower_SamplePSFPlot.gif (http://www.analyticcycling.com/ForcesPower_Page.html)

Sure at 10mph, your total load may be 50/50 rolling-resistance and aero-drag and you'll be burning up 20-25 cal/mile. However, aero-drag goes up to the square-power of speed and the power-required to overcome that drag goes up the cube-power of speed. So at 25mph, you need to expend 15-times more power to overcome aero-drag than at 10mph (even though rolling-resistance has only increased by 2.5-times). So you'll end up burning off 50-60 cal/mile @ 25mph. This is why cars get lower gas-mileage at higher-speeds...

Plugging 10 & 25mph on an MTB into the Kreuzotter.de site (http://www.kreuzotter.de/english/espeed.htm), I get:

10mph = 54 watts for 1-hour = 194400 J / 10 miles = 19440 J/mile
25mph = 492 watts for 1-hour = 1771200 J / 25 miles = 70848 J/mile

... or about 3.5x more energy expended per mile.

Going back to the OP's question, it's all based upon relative effort. If you ride as hard as you can for 1-hour on a hybrid vs. a sleek road-bike with TT-bars, you'll burn off roughly the same calories/hr. Just that the speeds will be different and you'll go faster on the road-bike and cover more distance for the same power-output and calories-burned; resulting in lower calories/mile on the road-bike than on the hybrid. However, total calories/hr will end up being the same. It's about effort-level and power-output and how hard you're pushing your body. The type of bike and the resultant speed doesn't make a difference in effort-level or total calories burned per hour. However, you'll go faster on a road-bike for the same power-output. :)

Been riding a hybrid for exercise but recently started shopping for a road bike so I can keep up with friends on faster road bike during casual rides - not interested in racing. Stopped by LBS in my shopping and the guy tells me that the road bike is better exercise because it is more efficient. I know it is more efficient in terms of speed and milage but that is not my objective during exercise.
From a calories per hour or general biking exercise standpoint, would the type of bike make any difference? I have been assuming that my calories per hour and general exercise benefits would be equal no matter what type of bike I am riding. One hour on a hybrid = one hour on a road bike.
Any evidence to the contrary?

There's two issues here, first is riding with friends and yes a road bike is generally more efficient at converting your power into forward motion. If you're struggling to keep up on the hybrid then a more agressive road bike will help a little. What will make a bigger difference is effective training and nutrition, which leads into the second issue.

From a purely cardio fitness perspective your body doesn't care what bike you're riding or even if you're walking, running, swimming, or any other aerobic activity. What does matter is how hard your heart is working, and for how long. To that end you can quantify just how effective our workout is with a heart rate monitor, its easily the best bang-for-buck accesory you can buy that will improve the effectiveness of your workouts. You'll know when you're in the right training zone for the results you're after, want to inprove your cardio efficiency? burn fat? raise your LT/VO2 max? they all require different sorts of training rides in different heart rate zones. You'll also be able to objectively see how you're improving over time and where you could focus your training.

As far as what the salesman is telling you, well, hes obviously a salesman and more interested in making the sale than in your fitness. Bottom line is go ahead an look at a nice, well fitting road bike but leave room in the budget for a heart rate monitor.

Thanks Danno. I had conveniently forgotten that air resistance increases as the square of speed. At my 12 to 16 mph speeds (not bad for an old man on a MTB :)) I'll continue to use 40 calories/mile as a rough approximation. Or is that figure too high?

Sounds about right? I guess it also depends upon how upright you're sitting and what kind of knobbies you've got, eh? ;)