Bicycle Computer Altimeter Accuracy

[Colin Campbell]

[email protected] wrote:
> On Tue, 18 Sep 2007 17:46:05 -0700, Colin Campbell
> <[email protected]> wrote:
>
>> Arthur Shapiro wrote:
>>> In article <[email protected]>, Colin Campbell <[email protected]> wrote:
>>>> Yesterday, I did one of Southern California's classic mountain rides -
>>>> Glendora Mountain Road. According to my bike computer, I did 1298
>>>> meters of climbing, and 1541 meters of descending (ending up exactly
>>>> where I started).
>>> For what it's worth, when I do GMR starting at Boulder Springs Road (the one
>>> stop light, a convenient place to park), my Cateye ranges between 4860 and
>>> 5240 feet of climbing for the ordinary back-and-forth to Mt. Baldy Village. I
>>> wish the results were more consistent.
>>>
>>> Art
>>>
>> Art,
>> I don't find a Boulder Springs Road using Google Maps. Where is that?
>>
>> I usually start from the 210 Freeway & Grand in Glendora. North on
>> Grand to Sierra Madre, east on Sierra Madre to GMR. Occasionally, we'll
>> start from Costco (W Foothill & Todd in Azusa). This past Sunday, we
>> started from a fellow club member's place in La Verne (I was mostly lost
>> at the start).
>> Colin
>
> Dear Colin,
>
> http://yellowpages.superpages.com/d...lay_mode=map&route_type=fastest&ROUTE_UNITS=2
>
> Cheers,
>
> Carl Fogel
Thanks, Carl. When are you coming to ride it?

Now I know that Art is short-cutting the route by starting at the very
base of the climb! Maybe I'll see his car next time I go.

It's funny that Google Maps wouldn't try to show me more "Boulder
Springs" choices when I had the "Road" part wrong. But now I know to
try other "types", like Avenue, Drive, Boulevard, etc. Also, when I
tried "Boulder Springs", Google Maps gave me a useless location in the
middle of the desert. I had to add "Glendora, CA" to get the right place.

 

[[email protected]]

On Tue, 18 Sep 2007 19:58:14 -0700, Colin Campbell
<[email protected]> wrote:

>[email protected] wrote:
>> On Tue, 18 Sep 2007 17:46:05 -0700, Colin Campbell
>> <[email protected]> wrote:
>>
>>> Arthur Shapiro wrote:
>>>> In article <[email protected]>, Colin Campbell <[email protected]> wrote:
>>>>> Yesterday, I did one of Southern California's classic mountain rides -
>>>>> Glendora Mountain Road. According to my bike computer, I did 1298
>>>>> meters of climbing, and 1541 meters of descending (ending up exactly
>>>>> where I started).
>>>> For what it's worth, when I do GMR starting at Boulder Springs Road (the one
>>>> stop light, a convenient place to park), my Cateye ranges between 4860 and
>>>> 5240 feet of climbing for the ordinary back-and-forth to Mt. Baldy Village. I
>>>> wish the results were more consistent.
>>>>
>>>> Art
>>>>
>>> Art,
>>> I don't find a Boulder Springs Road using Google Maps. Where is that?
>>>
>>> I usually start from the 210 Freeway & Grand in Glendora. North on
>>> Grand to Sierra Madre, east on Sierra Madre to GMR. Occasionally, we'll
>>> start from Costco (W Foothill & Todd in Azusa). This past Sunday, we
>>> started from a fellow club member's place in La Verne (I was mostly lost
>>> at the start).
>>> Colin
>>
>> Dear Colin,
>>
>> http://yellowpages.superpages.com/d...lay_mode=map&route_type=fastest&ROUTE_UNITS=2
>>
>> Cheers,
>>
>> Carl Fogel
>Thanks, Carl. When are you coming to ride it?
>
>Now I know that Art is short-cutting the route by starting at the very
>base of the climb! Maybe I'll see his car next time I go.
>
>It's funny that Google Maps wouldn't try to show me more "Boulder
>Springs" choices when I had the "Road" part wrong. But now I know to
>try other "types", like Avenue, Drive, Boulevard, etc. Also, when I
>tried "Boulder Springs", Google Maps gave me a useless location in the
>middle of the desert. I had to add "Glendora, CA" to get the right place.

Dear Colin,

Alas, too many roads, not enough time. But thanks for the invitation.

Let's not say that Art is short-cutting. Rather, he is honoring the
tradition of the early Tour de France riders, who sometimes abridged
the tedious official route with taxis and trains:

"Lifts: in the early years, riders would regularly grab a lift in
supporters' cars or else cling to them. In 1928, two riders jumped in
a taxi after the truck they were travelling in crashed into a ditch."

"Short cuts: in 1906, three riders caught the train to Dijon, but were
caught by Tour officials; three-time Tour winner Philippe Thys once
asked a shepherd for a short cut over the Col de Peyresourde, but got
lost on the track."

http://sport.independent.co.uk/general/article2740529.ece

At least he isn't chopping down trees to block the road:

"Trees: in 1904, fans blocked the road with felled trees to prevent
rival riders getting past."

Cheers,

Carl Fogel

 

[Arthur Shapiro]

>Let's not say that Art is short-cutting. Rather, he is honoring the
>tradition of the early Tour de France riders, who sometimes abridged
>the tedious official route with taxis and trains:


Hey, guys. I start there simply because that's the way my club has always
"advertised" the ride, with Boulder Springs being a nice neighborhood with
ample parking. There's no intent to cheat, although I realize it's a few
blocks up up from Sierra Whatchamacallit. If I have to ride down and back at
the end of the ride to be "pure", just tell me - I'm not scared of climbs.

Hell, I did the ski lifts three times in July, and threw in Little GMR down
and back one of those times for an 8340' day. The ski lifts in a 39x25 hurts,
Big Time. And I did GMR the day before Labor Day, and it was 109 degrees when
I got back to the car. So give me a break!

Art (grumble, grumble)

 

[[email protected]]

On Wed, 19 Sep 2007 04:28:42 GMT, [email protected] (Arthur
Shapiro) wrote:

>
>>Let's not say that Art is short-cutting. Rather, he is honoring the
>>tradition of the early Tour de France riders, who sometimes abridged
>>the tedious official route with taxis and trains:
>
>
>Hey, guys. I start there simply because that's the way my club has always
>"advertised" the ride, with Boulder Springs being a nice neighborhood with
>ample parking. There's no intent to cheat, although I realize it's a few
>blocks up up from Sierra Whatchamacallit. If I have to ride down and back at
>the end of the ride to be "pure", just tell me - I'm not scared of climbs.
>
>Hell, I did the ski lifts three times in July, and threw in Little GMR down
>and back one of those times for an 8340' day. The ski lifts in a 39x25 hurts,
>Big Time. And I did GMR the day before Labor Day, and it was 109 degrees when
>I got back to the car. So give me a break!
>
>Art (grumble, grumble)

Dear Art,

Sorry, just kidding!

I do understand that many posters on RBT aren't lucky enough to have a
nice ride starting from their driveway (like mine, though I dislike
that lone stoplight) and that driving to where your friends meet you
for a good ride makes sense.

With luck, Colin will show up at Boulder Springs some day and keep you
hon--

Er, company.

Hope your weather is more bearable with fall approaching.

Cheers,

Carl Fogel

 

[Artoi]

In article <[email protected]>,
Ron Hardin <[email protected]> wrote:

> Barometric is subject to wind effects ; if you open the window of a light
> airplane, the altimeter jumps a hundred feet.

There's truth in this. AIUI, iBike power meter uses this feature.

However, a well designed altimeter built for bikes should be immune to
this issue.
--

 

[Colin Campbell]

Arthur Shapiro wrote:
>> Let's not say that Art is short-cutting. Rather, he is honoring the
>> tradition of the early Tour de France riders, who sometimes abridged
>> the tedious official route with taxis and trains:
>
>
> Hey, guys. I start there simply because that's the way my club has always
> "advertised" the ride, with Boulder Springs being a nice neighborhood with
> ample parking. There's no intent to cheat, although I realize it's a few
> blocks up up from Sierra Whatchamacallit. If I have to ride down and back at
> the end of the ride to be "pure", just tell me - I'm not scared of climbs.
>
> Hell, I did the ski lifts three times in July, and threw in Little GMR down
> and back one of those times for an 8340' day. The ski lifts in a 39x25 hurts,
> Big Time. And I did GMR the day before Labor Day, and it was 109 degrees when
> I got back to the car. So give me a break!
>
> Art (grumble, grumble)

OK, Art, I'll give you the benefit of the doubt. I think I'm probably
already "slogging" when I get to that intersection, and that's why I
never noticed the street name. And I've sure never gone to the ski
lifts - people who CAN climb tell me it's darned tough, so kudos to you!

I did a beach loop on Labor Day (and it only got to 108F in Fullerton,
and 90F inside my house) - took me two days to recover from that. I
can't imagine what GMR would have done to me!

 

[Doc O'Leary]

In article <[email protected]>,
[email protected] (Booker Bense) wrote:

> In article
> <droleary.usenet-BAC011.13471918092007@sn-ip.vsrv-sjc.supernews.net>,
> Doc O'Leary <[email protected]> wrote:
> >In article <[email protected]>,
> > Colin Campbell <[email protected]> wrote:
> >
> >> Yesterday, I did one of Southern California's classic mountain rides -
> >> Glendora Mountain Road. According to my bike computer, I did 1298
> >> meters of climbing, and 1541 meters of descending (ending up exactly
> >> where I started).
> >>
> >> Is there any way of guessing which of these numbers might be more
> >> accurate?
> >
> >Flip a coin if you want to guess. If you want to *know*, go an online
> >map (and/or Google Earth) and measure the route.
> >
>
> Most topo programs provide even less accurate results that even
> the worst bike altimeter.

I'd like something more than your baseless claim to go on.

--
My personal UDP list: 127.0.0.1, 4ax.com, buzzardnews.com, googlegroups.com,
heapnode.com, localhost, teranews.com, x-privat.org

 

[Booker Bense]

In article <droleary.usenet-B2807C.14161719092007@sn-ip.vsrv-sjc.supernews.net>,
Doc O'Leary <[email protected]> wrote:
>In article <[email protected]>,
> [email protected] (Booker Bense) wrote:
>

>> Most topo programs provide even less accurate results that even
>> the worst bike altimeter.
>
>I'd like something more than your baseless claim to go on.
>

Old La Honda road in Woodside california. It goes up never down
and is 1300ft of climbing. I have yet see a topo program that
comes within 30% of the well know result.

Nearby is the well known Alpine-Portola Valley-Sandhill loop.
Every topo program I've tried ( except Klimb which cheats... )
gets the total climbing on that loop off by 50% or more.

_ Booker C. Bense

 

[Dorfus Dippintush]

[email protected] wrote:
> On Wed, 19 Sep 2007 04:28:42 GMT, [email protected] (Arthur
> Shapiro) wrote:
>
>>> Let's not say that Art is short-cutting. Rather, he is honoring the
>>> tradition of the early Tour de France riders, who sometimes abridged
>>> the tedious official route with taxis and trains:
>>
>> Hey, guys. I start there simply because that's the way my club has always
>> "advertised" the ride, with Boulder Springs being a nice neighborhood with
>> ample parking. There's no intent to cheat, although I realize it's a few
>> blocks up up from Sierra Whatchamacallit. If I have to ride down and back at
>> the end of the ride to be "pure", just tell me - I'm not scared of climbs.
>>
>> Hell, I did the ski lifts three times in July, and threw in Little GMR down
>> and back one of those times for an 8340' day. The ski lifts in a 39x25 hurts,
>> Big Time. And I did GMR the day before Labor Day, and it was 109 degrees when
>> I got back to the car. So give me a break!
>>
>> Art (grumble, grumble)
>
> Dear Art,
>
> Sorry, just kidding!
>
> I do understand that many posters on RBT aren't lucky enough to have a
> nice ride starting from their driveway (like mine, though I dislike
> that lone stoplight) and that driving to where your friends meet you
> for a good ride makes sense.
>
> With luck, Colin will show up at Boulder Springs some day and keep you
> hon--
>
> Er, company.
>
> Hope your weather is more bearable with fall approaching.
>
> Cheers,
>
> Carl Fogel

Our town has one stop light. We don't mind it because it gives visitors
the impression our town is busy.

Dorfus

 

[[email protected]]

On Sep 18, 10:25 pm, [email protected] wrote:
> On Sep 17, 11:30 pm, "[email protected]" <[email protected]>
> wrote:
>
> > > In certain circumstances, a bicycle power meter has greater resolution
> > > in measuring elevation change than either the consumer level
> > > altimeters or GPS receivers that one finds on bicycles.
>
> > Yesbut, resolution is not the same as accuracy, as you
> > know. It may be accurate under certain circumstances,
> > but in the mountains, there is often a wind blowing.
>
> Right, but the reason why most of us want to know the elevation gain
> is because elevation gain has come to be a proxy measure for effort.
>
> FWIW, take a look at this:http://anonymous.coward.free.fr/wattage/cda/indirect-cda.pdf

Hey, this is really cool! Have you tried publishing this in a sports
related journal?

> It's an old version and I've done a bit more with it since then, but
> notice that I picked out a drainage grate on the edge of a "flat"
> road. I'd appreciate your comments.

 

[Ron Hardin]

> > Right, but the reason why most of us want to know the elevation gain
> > is because elevation gain has come to be a proxy measure for effort.

It's not true, though.

Imagine that the road is a series of half foot hills, a wavy surface but
smoothly spaced, so you just ride over them.

There's almost no reduction in speed at the tops, and your average speed
is pretty exactly the same as without them.

Yet you gain thousands of feet over the ride, which is indistinguishable
effort-wise from an everywhere-level ride.

The energy you put into kinetic energy serves as a buffer that gives out
and takes back the energy of the height changes without any intervention
by you, except the normal keeping-up against level air resistance.
--
[email protected]

On the internet, nobody knows you're a jerk.

 

[Doc O'Leary]

In article <[email protected]>,
[email protected] (Booker Bense) wrote:

> In article
> <droleary.usenet-B2807C.14161719092007@sn-ip.vsrv-sjc.supernews.net>,
> Doc O'Leary <[email protected]> wrote:
> >In article <[email protected]>,
> > [email protected] (Booker Bense) wrote:
> >
>
> >> Most topo programs provide even less accurate results that even
> >> the worst bike altimeter.
> >
> >I'd like something more than your baseless claim to go on.
> >
>
> Old La Honda road in Woodside california. It goes up never down
> and is 1300ft of climbing. I have yet see a topo program that
> comes within 30% of the well know result.

So you're essentially saying you haven't bothered to try Google Earth or
Google Maps. Both give results that seem to be in the range you expect.
You're going to have to be much more specific on what the error is if
you want to be taken seriously.

> Nearby is the well known Alpine-Portola Valley-Sandhill loop.
> Every topo program I've tried ( except Klimb which cheats... )
> gets the total climbing on that loop off by 50% or more.

Compared to *what*? Please cite the "well know[n] results" you are so
certain are correct in the first place. And, for goodness sake, give
GPS coordinates (or a link) so that everyone who isn't "nearby" can more
easily figure out where the hell you're talking about.

--
My personal UDP list: 127.0.0.1, 4ax.com, buzzardnews.com, googlegroups.com,
heapnode.com, localhost, teranews.com, x-privat.org

 

[[email protected]]

On Sep 20, 11:03 am, Ron Hardin <[email protected]> wrote:

> Yet you gain thousands of feet over the ride, which is indistinguishable
> effort-wise from an everywhere-level ride.

Those two rides are distinguishable.

 

[Ron Hardin]

[email protected] wrote:
>
> On Sep 20, 11:03 am, Ron Hardin <[email protected]> wrote:
>
> > Yet you gain thousands of feet over the ride, which is indistinguishable
> > effort-wise from an everywhere-level ride.
>
> Those two rides are distinguishable.

Actually not. Your speed drops less for a given rise the higher your speed.

dE = V dV

or

dV = dE / V

where dE is the energy from the rise. dV the change in speed is less the
faster you're going.

You notice this at the bottom of a valley when you think you're going to
make it way, way up the next hill because you're not slowing down much,
an opinion you change when you've climbed about 20 feet, but not before.

At normal bicycle speeds, you'd never notice a half foot ``road wave.''

--
[email protected]

On the internet, nobody knows you're a jerk.

 

[Robert Chung]

On Sep 20, 4:35 pm, Ron Hardin <[email protected]> wrote:
> [email protected] wrote:
>
> > On Sep 20, 11:03 am, Ron Hardin <[email protected]> wrote:
>
> > > Yet you gain thousands of feet over the ride, which is indistinguishable
> > > effort-wise from an everywhere-level ride.
>
> > Those two rides are distinguishable.
>
> Actually not.

Actually, yes.

http://anonymous.coward.free.fr/wattage/cda/indirect-cda.pdf