Could air density make this much difference?

"BringYouToLife" wrote in message
m...
Ken, sometimes you might have a cold, you can have a bug or a cold for
a week or two, you may feel ok, but will ruin your athletic
performance. Try taking a couple days off.

That's interesting as I had a bad cold for the week before I
moved.

Ken

"Ken Bessler" wrote in message ...
I just moved from 5400 ft altitude to 700 ft. I've noticed about
a 15-25% decrease in performance or an equal amount of an
increase in effort to equal my old levels. This is a measurement
of speed, distance, cadence in average and maximums spread
over a 3 week period. All other factors (my weight, % & grade
of hills, road conditions, traffic, etc.) are equal.

Could the lower, denser air be making that much difference or
should I be inspecting my Bianchi for shipping damage? I gave
it the once & twice over when it arrived and all seemed well. I've
been too busy to take it to my LBS for a tune up/inspection.

Air resistance alone will slow you down about 1 MPH, according to the
Bicycle speed & power calculator:

http://www.kreuzotter.de/english/espeed.htm

(1MPh difference is assuming 160 watts power output on the flat as
well as some other things about the bike, tires, weight, etc.)

--Brent
bhugh[at]mwsc.edu
www.MoBikeFed.org

Brent Hugh wrote:
"Ken Bessler" wrote in message
...
I just moved from 5400 ft altitude to 700 ft. I've noticed about
a 15-25% decrease in performance or an equal amount of an
increase in effort to equal my old levels. This is a measurement
of speed, distance, cadence in average and maximums spread
over a 3 week period. All other factors (my weight, % & grade
of hills, road conditions, traffic, etc.) are equal.

Could the lower, denser air be making that much difference or
should I be inspecting my Bianchi for shipping damage? I gave
it the once & twice over when it arrived and all seemed well. I've
been too busy to take it to my LBS for a tune up/inspection.

Air resistance alone will slow you down about 1 MPH, according to the
Bicycle speed & power calculator:

http://www.kreuzotter.de/english/espeed.htm

(1MPh difference is assuming 160 watts power output on the flat as
well as some other things about the bike, tires, weight, etc.)

Nifty toy. Virtually nails the speed difference I see
when going from the top of the bars to the drops at the
same power output. (It ought to feed this difference back
out through the cadence variable also but for some reason
it doesn't).

But I don't think it takes into account the altitude when
calculating the calorie output. As I've posted before,
a reputable source (which of course I do not have the
bibliographic data for at the moment) indicates that every
100 feet in altitude is worth an extra 22 kcal per hour
of aerobic exercise (regardless of weight and the exact
level of effort).

--Blair
"YMMV"

Brent Hugh Wrote:
"Ken Bessler" wrote in message
...
I just moved from 5400 ft altitude to 700 ft. I've noticed about
a 15-25% decrease in performance or an equal amount of an
increase in effort to equal my old levels. This is a measurement
of speed, distance, cadence in average and maximums spread
over a 3 week period. All other factors (my weight, % & grade
of hills, road conditions, traffic, etc.) are equal.

Could the lower, denser air be making that much difference or
should I be inspecting my Bianchi for shipping damage? I gave
it the once & twice over when it arrived and all seemed well. I've
been too busy to take it to my LBS for a tune up/inspection.

Air resistance alone will slow you down about 1 MPH, according to the
Bicycle speed & power calculator:

http://www.kreuzotter.de/english/espeed.htm

(1MPh difference is assuming 160 watts power output on the flat as
well as some other things about the bike, tires, weight, etc.)

--Brent
bhugh[at]mwsc.edu
www.MoBikeFed.org
at such a lower power output, speed will not be affected as much by
the difference in air resistence. 1mph seems right, at 15-20mph.

the original poster should definitely see an increase in power output
at the same effort level. speed will be about the same, because of the
greater air resistence at a given speed. but he should be producing
more power because of the greater oxygen supply.
if he doesn't have a powermeter, then a good way to test this is to
climb some hills. he should feel like he is climbing hills faster at
sea level.


--
velomanct