Garmin Edge 305 or Edge 500 ??

"David Scheidt" wrote in message
...
MikeWhy wrote:
:"Peter Cole" wrote in message
...
: I love GPS -- for charting and speedometer/odometer functions when
direct
: measurement is difficult (e.g. boats). For bikes, we have a perfect
: odometer/speedometer simply by counting wheel revolutions, so I don't
see
: the justification for complex alternatives.

:The 705 recalculates tire circumference by comparing the spoke magnet
count
:to the satellite derived travel distance. It typically varies over the
:course of a ride, and for sure from day to day. What you're really
counting
:with that perfect odometer/speedometer is wheel revolutions, not distance
:travelled. I'm more interested in distance travelled than how many times
the
:wheel went around.

You know, the circumfrence of my tires simply doesn't change that
much. When it does, i stop and fix the flat. The accuracy of
counting wheel revolutions is greater than that of GPS.

Sure. I'll board this loonie bus. Let's see where it takes us.

You measured this how?

MikeWhy wrote:
"Peter Cole" wrote in message
...
I love GPS -- for charting and speedometer/odometer functions when
direct measurement is difficult (e.g. boats). For bikes, we have a
perfect odometer/speedometer simply by counting wheel revolutions, so
I don't see the justification for complex alternatives.

The 705 recalculates tire circumference by comparing the spoke magnet
count to the satellite derived travel distance. It typically varies over
the course of a ride, and for sure from day to day. What you're really
counting with that perfect odometer/speedometer is wheel revolutions,
not distance travelled. I'm more interested in distance travelled than
how many times the wheel went around.

Putting aside the issue of whether satellites are necessary to
continuously recalibrate wheel circumferences, I'll simply say that a
revolution counting odometer/speedometer has been more than adequate for
my purpose, which was to navigate via a cue sheet. I don't need an
atomic wris****ch, either.


I've had several wired (~$20) Cateyes, that never failed and never
even required new batteries. There's one in my tool box that's still
displaying the numbers from the last ride it was used on -- 7-8 years
ago.

I've never found anything better at measuring relative fitness than
riding the same loops with the same (mostly) set of riders. There are
so many variables day to day (wind, temperature) that the averages
aren't consistent, ranking is a much better indicator. Some people
follow "zone training", and try to spend planned intervals at
particular effort levels. My experience has been that after using a
HRM for a while I can estimate my rate pretty accurately, so there's
no real need to wear that damn strap any more.

Faced with real facts -- that is, power production as a measure of
fitness -- you would rely instead on physiological stress as an indirect
measure, and then offer that no measurement is even better. I am
impressed with the depth of your resolve to remain ignorant.

How is "power production" any more of a "real fact" than "physiological
stress"? Unless you're trying to achieve some kind of abstract fitness
(of your own definition), the usual ultimate goal of cycling fitness is
to ride further, faster. The easiest and most direct way to measure this
is to see how far and fast you can ride. Unless you have a track,
determining absolutes is impossible, so you might want to see how you
stack up against comparable riders. That's why we have races.

I've not seen any evidence that formal regimes help average cyclists
get much faster, that is any faster than someone who is just riding
hard a lot. Ride bike. Dropping (body) weight helps enormously, too.

My evidence is in my electronic log; you have it wrong about "just
riding hard a lot" being an effective training plan; and I'm not out to
sell you on anything.

You don't need electronics to set up a training program. You certainly
don't need an "electronic log".


I'm very confident you would dismiss any evidence
unexamined as inaccurate, incomplete, or inapplicable.

You read minds, too. Try presenting "evidence" instead of opinions, or a
"buyer's guide" and we'll see how it goes.

It does seem odd
that, to you, random thrashing about should be as effective as
disciplined and directed training,

Define "effective". Define "disciplined" and "directed". My definition
of "disciplined" is hauling your ass out of bed on a cold rainy morning
and cranking out the miles. It's grim business.


and your subjective "oh, I don't feel
so good today" is equal to even the HRM mismeasurement of physiological
stress from the effects of your diet, lost sleep, distraction, the day's
heat, humidity, and wind might substitute meaningfully for measured
performance.

I have no idea what you're trying to say in the above.

http://www.boston.com/bostonglobe/id...acts_backfire/

Yes, I subscribe. I read it in Sunday's paper.

The gist of the article is that people holding beliefs tend to filter
facts to suit. Duh.

Before you accuse me of filtering facts you might do me the courtesy of
presenting some.


Wouldn't it be easier to just say you don't care to spend the money, and
you don't have any serious interest?

I think I said both of those things, if not, let me be clear. I can't
see the point in spending money on useless gadgets unless for strictly
entertainment purposes. I'm not, at this time pursuing fitness goals
that a training regimen might deliver, but I have in the past. I know
many serious riders, for whom training programs are a way of life. They
are not "average".

It's perfectly clear to me that
your desire for continued ignorance does not in any way invalidate
anything I know, from measurements I made myself, or believe, from work
documented and published by others.

It's hard to know what you think I'm trying to "invalidate". Let me sum up:

I assume you are trying to cycle faster, rather than having some other
less direct goal like cardiac rehab or weight loss.

There are many different venues to ride faster in: road races, crits,
time trials, hill climbs, distance events, etc. There is no single
measure of fitness or performance.

There are many touted structured training regimes. They vary widely in
duration, hard days/recovery days, use of intervals, etc., etc. Some may
feel that a HRM is necessary to ride in "zones", but even those are
broad enough that estimates suffice. You don't need a Powertap. You
don't need a cadence counter. You don't need a GPS speedometer/odometer.
You might need a Timex. The most accurate things you probably need are
bathroom and kitchen scales.

MikeWhy wrote:

"David Scheidt" wrote in message
...
MikeWhy wrote:
:"Peter Cole" wrote in message
...
: I love GPS -- for charting and speedometer/odometer functions when
direct
: measurement is difficult (e.g. boats). For bikes, we have a perfect
: odometer/speedometer simply by counting wheel revolutions, so I
don't see
: the justification for complex alternatives.

:The 705 recalculates tire circumference by comparing the spoke magnet
count
:to the satellite derived travel distance. It typically varies over the
:course of a ride, and for sure from day to day. What you're really
counting
:with that perfect odometer/speedometer is wheel revolutions, not
distance
:travelled. I'm more interested in distance travelled than how many
times the
:wheel went around.

You know, the circumfrence of my tires simply doesn't change that
much. When it does, i stop and fix the flat. The accuracy of
counting wheel revolutions is greater than that of GPS.

Sure. I'll board this loonie bus. Let's see where it takes us.

You measured this how?

This is a silly subject since it presumes that even cheap bike
odometer/speedometers are insufficiently accurate -- which is the first
time I've heard that. But, putting that aside, a quick perusal of the
Garmin site didn't divulge any specification for the accuracy of the
odometer/speedometer. What is the spec and where did you find it?

"Peter Cole" wrote in message
...
MikeWhy wrote:

"David Scheidt" wrote in message
...
MikeWhy wrote:
:The 705 recalculates tire circumference by comparing the spoke magnet
count
:to the satellite derived travel distance. It typically varies over the
:course of a ride, and for sure from day to day. What you're really
counting
:with that perfect odometer/speedometer is wheel revolutions, not
distance
:travelled. I'm more interested in distance travelled than how many
times the
:wheel went around.

You know, the circumfrence of my tires simply doesn't change that
much. When it does, i stop and fix the flat. The accuracy of
counting wheel revolutions is greater than that of GPS.

Sure. I'll board this loonie bus. Let's see where it takes us.

You measured this how?

This is a silly subject since it presumes that even cheap bike
odometer/speedometers are insufficiently accurate -- which is the first
time I've heard that. But, putting that aside, a quick perusal of the
Garmin site didn't divulge any specification for the accuracy of the
odometer/speedometer. What is the spec and where did you find it?

Yes, it is silly, and it's going exactly where a smarter person would know
it would go as soon as you posted about the $20 CatEye and your odious tao
of non-measurement. Why don't we just stop this bus, and both get off and
walk away while we still can?

MikeWhy wrote:

"Peter Cole" wrote in message
...
MikeWhy wrote:

"David Scheidt" wrote in message
...
MikeWhy wrote:
:The 705 recalculates tire circumference by comparing the spoke
magnet count
:to the satellite derived travel distance. It typically varies over the
:course of a ride, and for sure from day to day. What you're really
counting
:with that perfect odometer/speedometer is wheel revolutions, not
distance
:travelled. I'm more interested in distance travelled than how many
times the
:wheel went around.

You know, the circumfrence of my tires simply doesn't change that
much. When it does, i stop and fix the flat. The accuracy of
counting wheel revolutions is greater than that of GPS.

Sure. I'll board this loonie bus. Let's see where it takes us.

You measured this how?

This is a silly subject since it presumes that even cheap bike
odometer/speedometers are insufficiently accurate -- which is the
first time I've heard that. But, putting that aside, a quick perusal
of the Garmin site didn't divulge any specification for the accuracy
of the odometer/speedometer. What is the spec and where did you find it?

Yes, it is silly, and it's going exactly where a smarter person would
know it would go as soon as you posted about the $20 CatEye and your
odious tao of non-measurement. Why don't we just stop this bus, and both
get off and walk away while we still can?



How about sharing one of your "facts"?

On Thu, 15 Jul 2010 09:59:00 -0500, "MikeWhy"
wrote:


"David Scheidt" wrote in message
...
MikeWhy wrote:
:"Peter Cole" wrote in message
...
: I love GPS -- for charting and speedometer/odometer functions when
direct
: measurement is difficult (e.g. boats). For bikes, we have a perfect
: odometer/speedometer simply by counting wheel revolutions, so I don't
see
: the justification for complex alternatives.

:The 705 recalculates tire circumference by comparing the spoke magnet
count
:to the satellite derived travel distance. It typically varies over the
:course of a ride, and for sure from day to day. What you're really
counting
:with that perfect odometer/speedometer is wheel revolutions, not distance
:travelled. I'm more interested in distance travelled than how many times
the
:wheel went around.

You know, the circumfrence of my tires simply doesn't change that
much. When it does, i stop and fix the flat. The accuracy of
counting wheel revolutions is greater than that of GPS.

Sure. I'll board this loonie bus. Let's see where it takes us.

You measured this how?

Dear Mike,

For what it's worth, here are the last few measurements from my daily
ride, second crack of the driveway and back, using a $15 Schwinn
cyclocomputer, which measures in thousandths of a mile:

15.331 new front tire, pumped up
15.315
51.316
15.319
15.292

[dropped 0.039 miles 15.331-15.292, 206 feet, 0.255%]

15.300 pumped tires
15.299 flat rear interrupted ride
15.287
15.295 flat rear interrupted ride
15.290
15.291
15.292
15.296 flat rear interrupted ride
15.295

[dropped 0.013 miles, 15.300-15.287, 69 feet, 0.085%

15.309 pumped tires

***

The odometer records the weaving path that the tires take down the
road and through corners, not straight-line geometry. For how far the
bicycle actually moves, it's inherently more accurate than
point-to-point GPS measurements. For point-to-point measurements, it's
inherently less accurate, giving a larger resulat.

Temperature affects the tire pressure and roll-out, varying from 70F
to 94F.

An unmarked U-turn on a 2-lane highway accounts for some variation--a
few feet off either way is doubled.

Sometimes the front wheel spins a little while I fix flats.

The tire slowly loses pressure, leading to lower readings.

My lines through corners and traffic aren't perfectly repeatable.

And my wobbling down the road gets worse with lower speeds and gears
into headwinds.

A thousandth of a mile is roughly a single wheelspin.

Cheers,

Carl Fogel

Peter Cole wrote:
MikeWhy wrote:

"Peter Cole" wrote in message
...
MikeWhy wrote:

"David Scheidt" wrote in message
...
MikeWhy wrote:
The 705 recalculates tire circumference by comparing the spoke
magnet count
to the satellite derived travel distance. It typically varies
over the course of a ride, and for sure from day to day. What
you're really counting with that perfect odometer/speedometer is
wheel revolutions, not distance travelled. I'm more interested
in distance travelled than how many times the wheel went around.

You know, the circumfrence of my tires simply doesn't change that
much. When it does, i stop and fix the flat. The accuracy of
counting wheel revolutions is greater than that of GPS.

Sure. I'll board this loonie bus. Let's see where it takes us.

You measured this how?

This is a silly subject since it presumes that even cheap bike
odometer/speedometers are insufficiently accurate -- which is the
first time I've heard that. But, putting that aside, a quick perusal
of the Garmin site didn't divulge any specification for the accuracy
of the odometer/speedometer. What is the spec and where did you
find it?

Yes, it is silly, and it's going exactly where a smarter person would
know it would go as soon as you posted about the $20 CatEye and your
odious tao of non-measurement. Why don't we just stop this bus, and
both get off and walk away while we still can?



How about sharing one of your "facts"?

Which one would you like to share? We'll call that one our's. How about this
one? The calculated 2112 mm circumference of my 700x28 rear differs from the
commonly published values. This value is meaningful and interesting to me
because, aside from the 60' error in a measured mile, it handily compares to
its unloaded circumference to yield a proportionality constant for the
tire's natural frequency. Which is meaningful in relation to the
transmissibility of road shocks to the rider's visceral mass. From this
scant nothingness, I can already discern that its resonant frequency is 31%
higher than that of my 26x2.1 MTB rear, at those inflation pressures. I
think that's a real juicy one. I'll set it aside and mark it as our's.

Op 15-7-2010 21:17, schreef:
On Thu, 15 Jul 2010 09:59:00 -0500, "MikeWhy"
wrote:


"David wrote in message
...
wrote:
:"Peter wrote in message
...
: I love GPS -- for charting and speedometer/odometer functions when
direct
: measurement is difficult (e.g. boats). For bikes, we have a perfect
: odometer/speedometer simply by counting wheel revolutions, so I don't
see
: the justification for complex alternatives.

:The 705 recalculates tire circumference by comparing the spoke magnet
count
:to the satellite derived travel distance. It typically varies over the
:course of a ride, and for sure from day to day. What you're really
counting
:with that perfect odometer/speedometer is wheel revolutions, not distance
:travelled. I'm more interested in distance travelled than how many times
the
:wheel went around.

You know, the circumfrence of my tires simply doesn't change that
much. When it does, i stop and fix the flat. The accuracy of
counting wheel revolutions is greater than that of GPS.

Sure. I'll board this loonie bus. Let's see where it takes us.

You measured this how?

Dear Mike,

For what it's worth, here are the last few measurements from my daily
ride, second crack of the driveway and back, using a $15 Schwinn
cyclocomputer, which measures in thousandths of a mile:

15.331 new front tire, pumped up
15.315
51.316
15.319
15.292

[dropped 0.039 miles 15.331-15.292, 206 feet, 0.255%]

15.300 pumped tires
15.299 flat rear interrupted ride
15.287
15.295 flat rear interrupted ride
15.290
15.291
15.292
15.296 flat rear interrupted ride
15.295

[dropped 0.013 miles, 15.300-15.287, 69 feet, 0.085%

15.309 pumped tires

***


This means that your ODO meter is consistent not accurate.

The odometer records the weaving path that the tires take down the
road and through corners, not straight-line geometry. For how far the
bicycle actually moves, it's inherently more accurate than
point-to-point GPS measurements. For point-to-point measurements, it's
inherently less accurate, giving a larger resulat.

Not that I care which one is more accurate but you made me curious. I
ride (almost) every year a race (cyclo we call it here) in the Dolomites
about 140 km and 4150m elevation with lots off curvy climbs and
decents. The last three times I used a Edge 305/705 GPS based . If I
look at my log I see that I measured:

2006, 136.69 km (Edge 305),
2007, 136.25 km (same Edge 305);
2010, 136.82 km (Edge 705).

So consistant within (0.57/136)*100 = 0.42% measured over 136 km and not
15 miles.

Lou

On Thu, 15 Jul 2010 14:42:01 -0400, Peter Cole
wrote:

MikeWhy wrote:

[---]

Yes, it is silly, and it's going exactly where a smarter person would
know it would go as soon as you posted about the $20 CatEye and your
odious tao of non-measurement. Why don't we just stop this bus, and both
get off and walk away while we still can?

How about sharing one of your "facts"?

Don't hold your breath ...

On Thu, 15 Jul 2010 14:55:41 +0000 (UTC), David Scheidt
wrote:

You know, the circumfrence of my tires simply doesn't change that
much. When it does, i stop and fix the flat. The accuracy of
counting wheel revolutions is greater than that of GPS.

Indeed it is. To the point where, over my regular 41km training
circuit, a small increase in the normally constant distance measured
is a sure indication that tyre pressure has dropped.