Accuracy of Calorie-counters on Cycle Computers?

Steve McDonald said:

I got a new Bell cycle computer (speedometer, etc.) and went for a
short spin to try it out. In just 6.3 miles, at average speed of 16
mph, it claimed I'd burned 363 extra calories. My weight is set at 200
lbs. Based on my experience in counting calories the old-fashioned way,
I'd be surprised if I'd actually used up even half this much energy.
How accurate have these calorie-counters seemed to other riders?

If this thing does work correctly, when I go for a 50-mile ride at
an even faster speed, I should be on the way to being a skeleton when I
finish. Maybe they figure if these computers generate a big "feel-good"
factor for hefty riders, they'll be more popular. Reminds me of how the
current administration measures the strength of the economy.

Another issue is whether the weight of the bike should be added to
that of the rider in the computer setting. This isn't specified in the
manual. Since my bikes range from 25 to 80 lbs. in total weight, this
would be a good idea.

Steve McDonald

Compare your results to this site.

http://www.caloriesperhour.com/index_burn.html

"Steve McDonald" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

I got a new Bell cycle computer (speedometer, etc.) and went for a
short spin to try it out. In just 6.3 miles, at average speed of 16
mph, it claimed I'd burned 363 extra calories. My weight is set at 200
lbs. Based on my experience in counting calories the old-fashioned way,
I'd be surprised if I'd actually used up even half this much energy.
How accurate have these calorie-counters seemed to other riders?

That doesn't sound very realistic to me. 40 calories per mile is a good
rule-of-thumb for cycling, and your computer is saying your burned close to
58 calories per mile. Since you're a larger rider, you could use 45
calories per mile, which would equal 284 calories for your ride.

Quoted message said:

If this thing does work correctly, when I go for a 50-mile ride at
an even faster speed, I should be on the way to being a skeleton when I
finish. Maybe they figure if these computers generate a big "feel-good"
factor for hefty riders, they'll be more popular. Reminds me of how the
current administration measures the strength of the economy.

They may, indeed, over-estimate calories burned for the reason you suggest.
I've always thought that gym equipment was programmed to the high side for
that reason.

Quoted message said:

Another issue is whether the weight of the bike should be added to
that of the rider in the computer setting. This isn't specified in the
manual. Since my bikes range from 25 to 80 lbs. in total weight, this
would be a good idea.

Steve McDonald

Oddly enough, bike weight doesn't make a huge difference, although 80 lbs
would have to be taken into account to be accurate (BTW, you need to get a
lighter bike!).

I've included a calorie and watts calculator in my CycliStats training
program (http://www.CycliStats.com) - it includes a bunch of different input
variables, including bike weight. You can download a free, 30-day trial
version, to see how the calorie calculator works, and play around with
various bike weights to see how it affects the calorie and watts
calculation.

--
~_-*
....G/ \G
http://www.CycliStats.com
CycliStats - Software for Cyclists

What are these things counting? I've seen calory meters attached to
speedometers, attached to workout equipment, counting heartbeats, etc.
Calories could be brake horsepower converted to the heat equivalent,
actual amount of calories expended (fuel loss) for the duration of the
exercise or for the exercise plus the effects over 48 hours, net work of
the bike+rider system, etc. I never got a straight answer on this. I
would think you would need 30 randomly selected people pedaling bikes
mounted on dynamometers inside calorimeter rooms to calibrate the
process, then mount a pitot tube for airspeed on the bike, add some
sprung weights and use both the heartrate and speedometer methods to get
an accurate value. Or is this stuff just more consumer toys?

--ag

[email hidden] (Steve McDonald) wrote in
news:[email hidden]:

Quoted message said:

I got a new Bell cycle computer (speedometer, etc.) and went for
a
short spin to try it out. In just 6.3 miles, at average speed of 16
mph, it claimed I'd burned 363 extra calories. My weight is set at
200 lbs. Based on my experience in counting calories the
old-fashioned way, I'd be surprised if I'd actually used up even half
this much energy. How accurate have these calorie-counters seemed to
other riders?

If this thing does work correctly, when I go for a 50-mile ride
at
an even faster speed, I should be on the way to being a skeleton when
I finish. Maybe they figure if these computers generate a big
"feel-good" factor for hefty riders, they'll be more popular. Reminds
me of how the current administration measures the strength of the
economy.

Another issue is whether the weight of the bike should be added
to
that of the rider in the computer setting. This isn't specified in
the manual. Since my bikes range from 25 to 80 lbs. in total weight,
this would be a good idea.

Steve McDonald

Andy Gee said:

What are these things counting? I've seen calory meters attached to
speedometers, attached to workout equipment, counting heartbeats, etc.
Calories could be brake horsepower converted to the heat equivalent,
actual amount of calories expended (fuel loss) for the duration of the
exercise or for the exercise plus the effects over 48 hours, net work of
the bike+rider system, etc. I never got a straight answer on this. I
would think you would need 30 randomly selected people pedaling bikes
mounted on dynamometers inside calorimeter rooms to calibrate the
process, then mount a pitot tube for airspeed on the bike, add some
sprung weights and use both the heartrate and speedometer methods to get
an accurate value. Or is this stuff just more consumer toys?

--ag

My HRM has a calorie counter. You input weight, activity level, and
set ranges.
I compared my last ride to the site that Beverly posted. It was very,
very close.

I think the ones that don't take heart rate as part of the caculation,
may not be all that accurate. But if they are consistent, you can see
if you are burning more or less. It would give you an idea of
improvement.

Life is Good!
Jeff

(Steve McDonald) said:

I got a new Bell cycle computer (speedometer, etc.) and went for a
short spin to try it out. In just 6.3 miles, at average speed of 16
mph, it claimed I'd burned 363 extra calories. My weight is set at 200
lbs. Based on my experience in counting calories the old-fashioned way,
I'd be surprised if I'd actually used up even half this much energy.
How accurate have these calorie-counters seemed to other riders?

If this thing does work correctly, when I go for a 50-mile ride at
an even faster speed, I should be on the way to being a skeleton when I
finish. Maybe they figure if these computers generate a big "feel-good"
factor for hefty riders, they'll be more popular. Reminds me of how the
current administration measures the strength of the economy.

Another issue is whether the weight of the bike should be added to
that of the rider in the computer setting. This isn't specified in the
manual. Since my bikes range from 25 to 80 lbs. in total weight, this
would be a good idea.

Steve McDonald

I had one of those a year or so ago and when I checked the computer
results against multiple other ways of calculating the *approximate*
calorie consumption it was fairly accurate. It knows the major
factors - your weight (you could always add some pounds to account for
the bike), riding time, riding speed and might make assumptions as to
bike/wheel type based on wheel size. Confirming calcs that took
similar factors into consideration were within 100 calories or so.

The problem I had with it was that it got finicky after about 3 months
and I was constantly having to tweak the magent alignment. I replaced
it with a CatEye and havent had to touch it once.