Wheel weight

On Tuesday, March 5, 2019 at 2:41:33 PM UTC-8, James wrote:
On 6/3/19 2:48 am, wrote:
On Tuesday, March 5, 2019 at 7:45:36 AM UTC-8, wrote:


The carbon clinchers: Front; 1.13 Kg Rear with 11-29 cassette; 1.58 Kg.

That is with tires and tubes. And the speedo magnet.


If you changed to a Garmin or other GPS based speedometer, you could
save valuable grams from the front wheel because there's no need for a
magnet.

--
JS

Firstly a GPS based system is not accurate - all of those ups and downs are not counted and on a long ride can add up to several miles. Secondly, the wheel magnets I use weigh less than one gram.

I am always amazed that people think that "modern technology" is better than older simply because it is newer.

On Tuesday, March 5, 2019 at 5:47:46 PM UTC-8, John B. Slocomb wrote:
On Tue, 5 Mar 2019 16:44:03 -0800, "Mark J."
wrote:

On 3/5/2019 3:20 PM, John B. Slocomb wrote:
On Wed, 6 Mar 2019 09:41:29 +1100, James
wrote:

On 6/3/19 2:48 am, wrote:
On Tuesday, March 5, 2019 at 7:45:36 AM UTC-8, wrote:


The carbon clinchers: Front; 1.13 Kg Rear with 11-29 cassette; 1.58 Kg.

That is with tires and tubes. And the speedo magnet.


If you changed to a Garmin or other GPS based speedometer, you could
save valuable grams from the front wheel because there's no need for a
magnet.

I've always been a little skeptical about GPS calculated measurements.
I remember back when we lived on the boat the GPS would sometimes
measure the altitude at 10 feet which was about twice the height above
sea level that the receiving antenna was mounted at.

As you should be; GPS has a notoriously large margin of error for
measuring altitude.

I think it's the trigonometry of the computation; the GPS (as I
understand it) measures distance to a collection of satellites whose
positions are well known, then computes location from triangulating the
results. I'm guessing that since most of the satellites are usually not
directly overhead, but rather the line of sight to the satellite is
usually be much closer to tangential to the earth, then very small
errors in the distance-to-satellite computation turn into much larger
errors in the altitude computation.

I think this is why higher-end bike GPS's have a pressure-based
altimeter as well, to correct the fluctuations in the GPS-computed
altitude. I know my Garmin Edge's regularly solicit known altitude
input at the start of a course.

Mark J.

I'm not sure about how accurate GPS really is but back in the day, the
seismic folks had a large "Black Box" that they used to locate their
seismic lines on the chart that they said was accurate to within feet.

--
Cheers,
John B.

There is a great deal of difference between positional accuracy and actual ground distance traveled.

On 3/6/2019 9:35 AM, Zen Cycle wrote:

I also remember the cornering issue. I bought a rather nice garmin unit about ten years ago, and was frustrated when I found out the averaging was locked at 5 seconds (if there was a way to decrease the sampling interval, I couldn't find it).

"Couldn't find it" is a beef I have with lots of electronic devices.

About a week ago, the GPS in my car showed me a display I'd never seen
befo a complete list of all the satellites it could see. I'd been
fumbling with it in the dark (not driving) and I couldn't see how I'd
gotten that display. But I needed to get going so I thought "I'll look
into it later."

A few days later I spent a good five minutes going through every menu I
could find. I never located that satellite display again.

That GPS is old, sort of primitive, and I seldom update it. For me, the
problem is worst for devices for which they push updates. "Oh look,
they've updated the interface for that app! _Now_ how do I get it to do
what I want?"

--
- Frank Krygowski

On 3/6/2019 9:02 AM, AMuzi wrote:
On 3/5/2019 9:55 PM, jbeattie wrote:

I have no instrumentation. I like surprises at the end of the ride
when I ask my fully instrumented riding buddies how far we went and
how much we climbed -- then I round up. No data to prove me wrong. I
adopt my son's power data when we're riding together since we're both
about the same weight, although he is all muscle and I'm muscle and
other things.Â* He gave me a Stages GPS Garmin-ish thing from work, but
I haven't put it on my bike. It sends me an e-mail every week
reminding me that I haven't ridden any miles.Â* That's super helpful.


+1
I don't need to know; it's not why I ride.

Back in the mid-1980s I got my first cyclometer. For me, it was useful
motivation for training - as in "I'm only going 19 mph? I can go faster
than that!"

Nowadays the data is just depressing. I try not to look at it too much.

--
- Frank Krygowski

On Wednesday, March 6, 2019 at 11:16:38 AM UTC-5, Frank Krygowski wrote:
On 3/6/2019 9:35 AM, Zen Cycle wrote:

I also remember the cornering issue. I bought a rather nice garmin unit about ten years ago, and was frustrated when I found out the averaging was locked at 5 seconds (if there was a way to decrease the sampling interval, I couldn't find it).

"Couldn't find it" is a beef I have with lots of electronic devices.

About a week ago, the GPS in my car showed me a display I'd never seen
befo a complete list of all the satellites it could see. I'd been
fumbling with it in the dark (not driving) and I couldn't see how I'd
gotten that display. But I needed to get going so I thought "I'll look
into it later."

A few days later I spent a good five minutes going through every menu I
could find. I never located that satellite display again.

That GPS is old, sort of primitive, and I seldom update it. For me, the
problem is worst for devices for which they push updates. "Oh look,
they've updated the interface for that app! _Now_ how do I get it to do
what I want?"


gawd I hate that!

On Wednesday, March 6, 2019 at 3:29:13 PM UTC+1, duane wrote:
On 06/03/2019 9:02 a.m., AMuzi wrote:
On 3/5/2019 9:55 PM, jbeattie wrote:
On Tuesday, March 5, 2019 at 7:28:17 PM UTC-8, James wrote:
On 6/3/19 12:47 pm, John B. Slocomb wrote:
On Tue, 5 Mar 2019 16:44:03 -0800, "Mark J."
wrote:


I think it's the trigonometry of the computation; the GPS (as I
understand it) measures distance to a collection of satellites whose
positions are well known, then computes location from triangulating
the
results.Â* I'm guessing that since most of the satellites are
usually not
directly overhead, but rather the line of sight to the satellite is
usually be much closer to tangential to the earth, then very small
errors in the distance-to-satellite computation turn into much larger
errors in the altitude computation.

I think this is why higher-end bike GPS's have a pressure-based
altimeter as well, to correct the fluctuations in the GPS-computed
altitude.Â* I know my Garmin Edge's regularly solicit known altitude
input at the start of a course.


I'm not sure about how accurate GPS really is but back in the day, the
seismic folks had a large "Black Box" that they used to locate their
seismic lines on the chart that they said was accurate to within feet.

On Wednesday, March 6, 2019 at 11:12:05 AM UTC-8, wrote:
On Wednesday, March 6, 2019 at 3:29:13 PM UTC+1, duane wrote:
On 06/03/2019 9:02 a.m., AMuzi wrote:
On 3/5/2019 9:55 PM, jbeattie wrote:
On Tuesday, March 5, 2019 at 7:28:17 PM UTC-8, James wrote:
On 6/3/19 12:47 pm, John B. Slocomb wrote:
On Tue, 5 Mar 2019 16:44:03 -0800, "Mark J."
wrote:


I think it's the trigonometry of the computation; the GPS (as I
understand it) measures distance to a collection of satellites whose
positions are well known, then computes location from triangulating
the
results.Â* I'm guessing that since most of the satellites are
usually not
directly overhead, but rather the line of sight to the satellite is
usually be much closer to tangential to the earth, then very small
errors in the distance-to-satellite computation turn into much larger
errors in the altitude computation.

I think this is why higher-end bike GPS's have a pressure-based
altimeter as well, to correct the fluctuations in the GPS-computed
altitude.Â* I know my Garmin Edge's regularly solicit known altitude
input at the start of a course.


I'm not sure about how accurate GPS really is but back in the day, the
seismic folks had a large "Black Box" that they used to locate their
seismic lines on the chart that they said was accurate to within feet.


Mark is pretty close to the correct reason. Most GPS receivers
intentionally track satellites that are close to the horizon as opposed
to direct overhead.Â* This is so that the X-Y part of the position
information is most accurate, at the expense of less accurate Z
position.


The overall accuracy depends greatly on the GPS receiver quality.Â* The
cheap receivers (say $50 ea) may be within a few meters, while expensive
receivers ($500) are 10 times better.Â* If you pay more ($10,000) and
incorporate corrections for atmospheric conditions and such, accuracy
can be better still.

The difference between cheap and expensive is largely down to the
stability of the oscillator used to time signals.Â* The antennas can also
be an expensive part and play a big role in accuracy and reflected
signal rejection.

But...Â* Even cheap GPS receivers are relatively stable over a short
time.Â* They usually produce a position, speed and heading once per
second.Â* The previous position, speed and heading are combined with new
measurements in a special filter, that usually results in better
accuracy than if the measurements were used alone.

The only times I've noticed real problems is when you cycle relatively
fast around tight corners.Â* The GPS position effectively cuts a little
off the corner each time, modelling it as a series of straight lines.
Hence your road speed appears to be slower than it really is and you
appear to accelerate again when the road straightens out.

More expensive GPS receivers can produce calculated position results
more frequently than 1 per second.Â* More powerful processor.Â* More power
consumption.Â* Unlikely to be in a battery operated consumer grade bike
computer.

But I find that they are accurate enough not to miss the magnet and reed
switch.

I have no instrumentation. I like surprises at the end of the ride
when I ask my fully instrumented riding buddies how far we went and
how much we climbed -- then I round up. No data to prove me wrong. I
adopt my son's power data when we're riding together since we're both
about the same weight, although he is all muscle and I'm muscle and
other things.Â* He gave me a Stages GPS Garmin-ish thing from work, but
I haven't put it on my bike. It sends me an e-mail every week
reminding me that I haven't ridden any miles.Â* That's super helpful.

-- Jay Beattie.





+1
I don't need to know; it's not why I ride.


I, on the other hand, am pretty wired up with my Garmin and Strava and
RideWithGPS. I like the stats to show my progress. I find the GPS helps
me when leading groups on rides that I don't know the route so well.
Less problematic than paper maps.

What's cool about cycling is that we are both happy with what we have.

GPS based cycling computers with navagation capabilities is one of the best and niciest cycling accesory IMO. Everything in one unit, never have to stop to look at a map, automatic logging and uploading, easy swap between bikes, clean cockpit, user definable datafield (number and content). What is there not to like?

https://photos.app.goo.gl/R11bCJx9DAaYHuDQA (map, cadence and power)

After my last crash we had a discussion with the insurance company of the woman I crashed into about my speed at the time of the crash. She accused me of excessive speed. I knew exactly my speed:

https://photos.app.goo.gl/vt8X8cetjpNfotfd9

That was settled then.

Lou

If you're not sure where you're going and they have a BICYCLE navigation feature they have advantages. But I can do the same thing with my smart phone minus the altitude function.

On Wednesday, March 6, 2019 at 8:41:40 PM UTC+1, wrote:
On Wednesday, March 6, 2019 at 11:12:05 AM UTC-8, wrote:
On Wednesday, March 6, 2019 at 3:29:13 PM UTC+1, duane wrote:
On 06/03/2019 9:02 a.m., AMuzi wrote:
On 3/5/2019 9:55 PM, jbeattie wrote:
On Tuesday, March 5, 2019 at 7:28:17 PM UTC-8, James wrote:
On 6/3/19 12:47 pm, John B. Slocomb wrote:
On Tue, 5 Mar 2019 16:44:03 -0800, "Mark J."
wrote:


I think it's the trigonometry of the computation; the GPS (as I
understand it) measures distance to a collection of satellites whose
positions are well known, then computes location from triangulating
the
results.Â* I'm guessing that since most of the satellites are
usually not
directly overhead, but rather the line of sight to the satellite is
usually be much closer to tangential to the earth, then very small
errors in the distance-to-satellite computation turn into much larger
errors in the altitude computation.

I think this is why higher-end bike GPS's have a pressure-based
altimeter as well, to correct the fluctuations in the GPS-computed
altitude.Â* I know my Garmin Edge's regularly solicit known altitude
input at the start of a course.


I'm not sure about how accurate GPS really is but back in the day, the
seismic folks had a large "Black Box" that they used to locate their
seismic lines on the chart that they said was accurate to within feet.


Mark is pretty close to the correct reason. Most GPS receivers
intentionally track satellites that are close to the horizon as opposed
to direct overhead.Â* This is so that the X-Y part of the position
information is most accurate, at the expense of less accurate Z
position.


The overall accuracy depends greatly on the GPS receiver quality.Â* The
cheap receivers (say $50 ea) may be within a few meters, while expensive
receivers ($500) are 10 times better.Â* If you pay more ($10,000) and
incorporate corrections for atmospheric conditions and such, accuracy
can be better still.

The difference between cheap and expensive is largely down to the
stability of the oscillator used to time signals.Â* The antennas can also
be an expensive part and play a big role in accuracy and reflected
signal rejection.

But...Â* Even cheap GPS receivers are relatively stable over a short
time.Â* They usually produce a position, speed and heading once per
second.Â* The previous position, speed and heading are combined with new
measurements in a special filter, that usually results in better
accuracy than if the measurements were used alone.

The only times I've noticed real problems is when you cycle relatively
fast around tight corners.Â* The GPS position effectively cuts a little
off the corner each time, modelling it as a series of straight lines.
Hence your road speed appears to be slower than it really is and you
appear to accelerate again when the road straightens out.

More expensive GPS receivers can produce calculated position results
more frequently than 1 per second.Â* More powerful processor.Â* More power
consumption.Â* Unlikely to be in a battery operated consumer grade bike
computer.

But I find that they are accurate enough not to miss the magnet and reed
switch.

I have no instrumentation. I like surprises at the end of the ride
when I ask my fully instrumented riding buddies how far we went and
how much we climbed -- then I round up. No data to prove me wrong. I
adopt my son's power data when we're riding together since we're both
about the same weight, although he is all muscle and I'm muscle and
other things.Â* He gave me a Stages GPS Garmin-ish thing from work, but
I haven't put it on my bike. It sends me an e-mail every week
reminding me that I haven't ridden any miles.Â* That's super helpful.

-- Jay Beattie.





+1
I don't need to know; it's not why I ride.


I, on the other hand, am pretty wired up with my Garmin and Strava and
RideWithGPS. I like the stats to show my progress. I find the GPS helps
me when leading groups on rides that I don't know the route so well.
Less problematic than paper maps.

What's cool about cycling is that we are both happy with what we have..

GPS based cycling computers with navagation capabilities is one of the best and niciest cycling accesory IMO. Everything in one unit, never have to stop to look at a map, automatic logging and uploading, easy swap between bikes, clean cockpit, user definable datafield (number and content). What is there not to like?

https://photos.app.goo.gl/R11bCJx9DAaYHuDQA (map, cadence and power)

After my last crash we had a discussion with the insurance company of the woman I crashed into about my speed at the time of the crash. She accused me of excessive speed. I knew exactly my speed:

https://photos.app.goo.gl/vt8X8cetjpNfotfd9

That was settled then.

Lou

If you're not sure where you're going and they have a BICYCLE navigation feature they have advantages. But I can do the same thing with my smart phone minus the altitude function.

I doubt that. Does your phone have a battery life of 15-20 hours with the screen on? Can you use your phone in the rain without a clumsy cover?

Lou

On 06/03/2019 2:12 p.m., wrote:
On Wednesday, March 6, 2019 at 3:29:13 PM UTC+1, duane wrote:
On 06/03/2019 9:02 a.m., AMuzi wrote:
On 3/5/2019 9:55 PM, jbeattie wrote:
On Tuesday, March 5, 2019 at 7:28:17 PM UTC-8, James wrote:
On 6/3/19 12:47 pm, John B. Slocomb wrote:
On Tue, 5 Mar 2019 16:44:03 -0800, "Mark J."
wrote:


I think it's the trigonometry of the computation; the GPS (as I
understand it) measures distance to a collection of satellites whose
positions are well known, then computes location from triangulating
the
results.Â* I'm guessing that since most of the satellites are
usually not
directly overhead, but rather the line of sight to the satellite is
usually be much closer to tangential to the earth, then very small
errors in the distance-to-satellite computation turn into much larger
errors in the altitude computation.

I think this is why higher-end bike GPS's have a pressure-based
altimeter as well, to correct the fluctuations in the GPS-computed
altitude.Â* I know my Garmin Edge's regularly solicit known altitude
input at the start of a course.


I'm not sure about how accurate GPS really is but back in the day, the
seismic folks had a large "Black Box" that they used to locate their
seismic lines on the chart that they said was accurate to within feet.


Mark is pretty close to the correct reason. Most GPS receivers
intentionally track satellites that are close to the horizon as opposed
to direct overhead.Â* This is so that the X-Y part of the position
information is most accurate, at the expense of less accurate Z
position.


The overall accuracy depends greatly on the GPS receiver quality.Â* The
cheap receivers (say $50 ea) may be within a few meters, while expensive
receivers ($500) are 10 times better.Â* If you pay more ($10,000) and
incorporate corrections for atmospheric conditions and such, accuracy
can be better still.

The difference between cheap and expensive is largely down to the
stability of the oscillator used to time signals.Â* The antennas can also
be an expensive part and play a big role in accuracy and reflected
signal rejection.

But...Â* Even cheap GPS receivers are relatively stable over a short
time.Â* They usually produce a position, speed and heading once per
second.Â* The previous position, speed and heading are combined with new
measurements in a special filter, that usually results in better
accuracy than if the measurements were used alone.

The only times I've noticed real problems is when you cycle relatively
fast around tight corners.Â* The GPS position effectively cuts a little
off the corner each time, modelling it as a series of straight lines.
Hence your road speed appears to be slower than it really is and you
appear to accelerate again when the road straightens out.

More expensive GPS receivers can produce calculated position results
more frequently than 1 per second.Â* More powerful processor.Â* More power
consumption.Â* Unlikely to be in a battery operated consumer grade bike
computer.

But I find that they are accurate enough not to miss the magnet and reed
switch.

I have no instrumentation. I like surprises at the end of the ride
when I ask my fully instrumented riding buddies how far we went and
how much we climbed -- then I round up. No data to prove me wrong. I
adopt my son's power data when we're riding together since we're both
about the same weight, although he is all muscle and I'm muscle and
other things.Â* He gave me a Stages GPS Garmin-ish thing from work, but
I haven't put it on my bike. It sends me an e-mail every week
reminding me that I haven't ridden any miles.Â* That's super helpful.

-- Jay Beattie.





+1
I don't need to know; it's not why I ride.


I, on the other hand, am pretty wired up with my Garmin and Strava and
RideWithGPS. I like the stats to show my progress. I find the GPS helps
me when leading groups on rides that I don't know the route so well.
Less problematic than paper maps.

What's cool about cycling is that we are both happy with what we have.

GPS based cycling computers with navagation capabilities is one of the best and niciest cycling accesory IMO. Everything in one unit, never have to stop to look at a map, automatic logging and uploading, easy swap between bikes, clean cockpit, user definable datafield (number and content). What is there not to like?

https://photos.app.goo.gl/R11bCJx9DAaYHuDQA (map, cadence and power)


Yep.

After my last crash we had a discussion with the insurance company of the woman I crashed into about my speed at the time of the crash. She accused me of excessive speed. I knew exactly my speed:

https://photos.app.goo.gl/vt8X8cetjpNfotfd9

That was settled then.

Lou



Ah, an additional benefit that didn't occur to me!

On 06/03/2019 2:51 p.m., wrote:
On Wednesday, March 6, 2019 at 8:41:40 PM UTC+1, wrote:
On Wednesday, March 6, 2019 at 11:12:05 AM UTC-8, wrote:
On Wednesday, March 6, 2019 at 3:29:13 PM UTC+1, duane wrote:
On 06/03/2019 9:02 a.m., AMuzi wrote:
On 3/5/2019 9:55 PM, jbeattie wrote:
On Tuesday, March 5, 2019 at 7:28:17 PM UTC-8, James wrote:
On 6/3/19 12:47 pm, John B. Slocomb wrote:
On Tue, 5 Mar 2019 16:44:03 -0800, "Mark J."
wrote:


I think it's the trigonometry of the computation; the GPS (as I
understand it) measures distance to a collection of satellites whose
positions are well known, then computes location from triangulating
the
results.Â* I'm guessing that since most of the satellites are
usually not
directly overhead, but rather the line of sight to the satellite is
usually be much closer to tangential to the earth, then very small
errors in the distance-to-satellite computation turn into much larger
errors in the altitude computation.

I think this is why higher-end bike GPS's have a pressure-based
altimeter as well, to correct the fluctuations in the GPS-computed
altitude.Â* I know my Garmin Edge's regularly solicit known altitude
input at the start of a course.


I'm not sure about how accurate GPS really is but back in the day, the
seismic folks had a large "Black Box" that they used to locate their
seismic lines on the chart that they said was accurate to within feet.


Mark is pretty close to the correct reason. Most GPS receivers
intentionally track satellites that are close to the horizon as opposed
to direct overhead.Â* This is so that the X-Y part of the position
information is most accurate, at the expense of less accurate Z
position.


The overall accuracy depends greatly on the GPS receiver quality.Â* The
cheap receivers (say $50 ea) may be within a few meters, while expensive
receivers ($500) are 10 times better.Â* If you pay more ($10,000) and
incorporate corrections for atmospheric conditions and such, accuracy
can be better still.

The difference between cheap and expensive is largely down to the
stability of the oscillator used to time signals.Â* The antennas can also
be an expensive part and play a big role in accuracy and reflected
signal rejection.

But...Â* Even cheap GPS receivers are relatively stable over a short
time.Â* They usually produce a position, speed and heading once per
second.Â* The previous position, speed and heading are combined with new
measurements in a special filter, that usually results in better
accuracy than if the measurements were used alone.

The only times I've noticed real problems is when you cycle relatively
fast around tight corners.Â* The GPS position effectively cuts a little
off the corner each time, modelling it as a series of straight lines.
Hence your road speed appears to be slower than it really is and you
appear to accelerate again when the road straightens out.

More expensive GPS receivers can produce calculated position results
more frequently than 1 per second.Â* More powerful processor.Â* More power
consumption.Â* Unlikely to be in a battery operated consumer grade bike
computer.

But I find that they are accurate enough not to miss the magnet and reed
switch.

I have no instrumentation. I like surprises at the end of the ride
when I ask my fully instrumented riding buddies how far we went and
how much we climbed -- then I round up. No data to prove me wrong. I
adopt my son's power data when we're riding together since we're both
about the same weight, although he is all muscle and I'm muscle and
other things.Â* He gave me a Stages GPS Garmin-ish thing from work, but
I haven't put it on my bike. It sends me an e-mail every week
reminding me that I haven't ridden any miles.Â* That's super helpful.

-- Jay Beattie.





+1
I don't need to know; it's not why I ride.


I, on the other hand, am pretty wired up with my Garmin and Strava and
RideWithGPS. I like the stats to show my progress. I find the GPS helps
me when leading groups on rides that I don't know the route so well.
Less problematic than paper maps.

What's cool about cycling is that we are both happy with what we have.

GPS based cycling computers with navagation capabilities is one of the best and niciest cycling accesory IMO. Everything in one unit, never have to stop to look at a map, automatic logging and uploading, easy swap between bikes, clean cockpit, user definable datafield (number and content). What is there not to like?

https://photos.app.goo.gl/R11bCJx9DAaYHuDQA (map, cadence and power)

After my last crash we had a discussion with the insurance company of the woman I crashed into about my speed at the time of the crash. She accused me of excessive speed. I knew exactly my speed:

https://photos.app.goo.gl/vt8X8cetjpNfotfd9

That was settled then.

Lou

If you're not sure where you're going and they have a BICYCLE navigation feature they have advantages. But I can do the same thing with my smart phone minus the altitude function.

I doubt that. Does your phone have a battery life of 15-20 hours with the screen on? Can you use your phone in the rain without a clumsy cover?

Lou


I tried with my iPhone as well using RideWithGPS. In addition to your
points, I was rarely able to see the screen on sunny days.