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New Computer Installation



 
 
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  #1  
Old May 3rd 07, 07:48 PM posted to rec.bicycles.tech
Yme
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Posts: 3
Default New Computer Installation

I have recently purchased a new CatEye computer for my bike.
In the past the computer that I have installed stated in the
instructions that the magnet should be placed as close to the
axle as possible. With my new computer the sensor/magnet is
placed about midway on the fork. Nothing in the instructions
state how high or low on the fork the sensor should go. If
the sensor is placed at a random height, won't this throw
off the accuracy of the computer? If the magnet is not
placed as close to the axle as possible, won't this throw
off the balance of the wheel?
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  #2  
Old May 3rd 07, 08:18 PM posted to rec.bicycles.tech
Lou Holtman
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Posts: 627
Default New Computer Installation

Yme wrote:
I have recently purchased a new CatEye computer for my bike.
In the past the computer that I have installed stated in the
instructions that the magnet should be placed as close to the
axle as possible. With my new computer the sensor/magnet is
placed about midway on the fork. Nothing in the instructions
state how high or low on the fork the sensor should go. If
the sensor is placed at a random height, won't this throw
off the accuracy of the computer? If the magnet is not
placed as close to the axle as possible, won't this throw
off the balance of the wheel?


No.

Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)
  #3  
Old May 3rd 07, 10:44 PM posted to rec.bicycles.tech
Paul Cassel
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Posts: 264
Default New Computer Installation

Yme wrote:
I have recently purchased a new CatEye computer for my bike.
In the past the computer that I have installed stated in the
instructions that the magnet should be placed as close to the
axle as possible. With my new computer the sensor/magnet is
placed about midway on the fork. Nothing in the instructions
state how high or low on the fork the sensor should go. If
the sensor is placed at a random height, won't this throw
off the accuracy of the computer? If the magnet is not
placed as close to the axle as possible, won't this throw
off the balance of the wheel?


Let me expand a bit. The computer works as a counter - not a velocity
detector. The wheel goes once around at the hub as well as the rim with
neither part of the wheel having more revolutions than any other part of
the wheel.

The computer calculates number of wheel revolutions over time. So the
placement of the magnet / pickup isn't relevant to the measurement.
  #4  
Old May 4th 07, 12:04 AM posted to rec.bicycles.tech
A Muzi
external usenet poster
 
Posts: 4,551
Default New Computer Installation

Yme wrote:
I have recently purchased a new CatEye computer for my bike.
In the past the computer that I have installed stated in the
instructions that the magnet should be placed as close to the
axle as possible. With my new computer the sensor/magnet is
placed about midway on the fork. Nothing in the instructions
state how high or low on the fork the sensor should go. If
the sensor is placed at a random height, won't this throw
off the accuracy of the computer? If the magnet is not
placed as close to the axle as possible, won't this throw
off the balance of the wheel?


Not at all. Try sticking something twice as heavy near the magnet & test
ride it.
Cateyes seem best just below your caliper. Inside the sensor are two
reeds. The magnet pulls the steel one to touch the copper one,
signalling "one iteration" to the chip/clock. New in the the box, it's
preprogrammed for a 700-23. You can change that value using either the
supplied lookup table or riding over a paint spot on a sidewalk,
measuring dot-to-dot and entering that exact wheel travel. (decimal
meters, either as 2XXX or 2XX; depends on model)

It matters not where the sensor mounts - it still increments "one
iteration".
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
  #5  
Old May 4th 07, 12:46 PM posted to rec.bicycles.tech
Barnard Frederick
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Posts: 74
Default New Computer Installation

In article ,
says...

I have recently purchased a new CatEye computer for my bike.
In the past the computer that I have installed stated in the
instructions that the magnet should be placed as close to the
axle as possible. With my new computer the sensor/magnet is
placed about midway on the fork. Nothing in the instructions
state how high or low on the fork the sensor should go. If
the sensor is placed at a random height, won't this throw
off the accuracy of the computer? If the magnet is not
placed as close to the axle as possible, won't this throw
off the balance of the wheel?


One wheel revolution is still one wheel revolution no matter where the
sensor and magnet are. However, the placement of the sensor/magnet has
nothing to do with accuracy, but with how fast the magnet passes the
sensor. If the magnet passes the sensor too quickly, it may not have
time to register. That's why most instructions I have seen recommend
placing the sensor lower on the fork and closer to the hub.

I have used Cateye and Planet Bike computers and both of them work over
a fairly wide range of positions. The Cateye magnet is very small and
light. I even bought spares for my Planet Bike computers for that
reason. Bike wheels don't spin fast enough for wheel balance to be much
of a problem.
  #6  
Old May 4th 07, 07:22 PM posted to rec.bicycles.tech
Yme
external usenet poster
 
Posts: 3
Default New Computer Installation

On Fri, 04 May 2007 07:46:00 -0400, Barnard Frederick wrote:

So the computer sensor counts the number of revolutions, this along
with the wheel size is used to determine the distance traveled.
This is similar to how a pedometer works. How does the computer
determine the speed? I would assume how frequent the magnet passes
the sensor. The speedometer would indicate a faster speed when sensor
is closer to the axle, than when the sensor is faster away from the axle.
It seems if the sensor is an inch too high or too low on the fork the
speedometer would be off by less the 1 mile per hour probably less.
This make sense now thanks for everyones explanation.

In article ,
says...

I have recently purchased a new CatEye computer for my bike. In the past
the computer that I have installed stated in the instructions that the
magnet should be placed as close to the axle as possible. With my new
computer the sensor/magnet is placed about midway on the fork. Nothing
in the instructions state how high or low on the fork the sensor should
go. If the sensor is placed at a random height, won't this throw off the
accuracy of the computer? If the magnet is not placed as close to the
axle as possible, won't this throw off the balance of the wheel?


One wheel revolution is still one wheel revolution no matter where the
sensor and magnet are. However, the placement of the sensor/magnet has
nothing to do with accuracy, but with how fast the magnet passes the
sensor. If the magnet passes the sensor too quickly, it may not have time
to register. That's why most instructions I have seen recommend placing
the sensor lower on the fork and closer to the hub.

I have used Cateye and Planet Bike computers and both of them work over a
fairly wide range of positions. The Cateye magnet is very small and
light. I even bought spares for my Planet Bike computers for that reason.
Bike wheels don't spin fast enough for wheel balance to be much of a
problem.


  #7  
Old May 4th 07, 07:30 PM posted to rec.bicycles.tech
Yme
external usenet poster
 
Posts: 3
Default New Computer Installation

On Fri, 04 May 2007 07:46:00 -0400, Barnard Frederick wrote:

If we know the distance and the amount of time it took to
travel that distance, we can calculate the speed. So the
sensor can be place anywhere on the fork with out compromising
speed or distance traveled. Makes perfect sense know.

In article ,
says...

I have recently purchased a new CatEye computer for my bike. In the past
the computer that I have installed stated in the instructions that the
magnet should be placed as close to the axle as possible. With my new
computer the sensor/magnet is placed about midway on the fork. Nothing
in the instructions state how high or low on the fork the sensor should
go. If the sensor is placed at a random height, won't this throw off the
accuracy of the computer? If the magnet is not placed as close to the
axle as possible, won't this throw off the balance of the wheel?


One wheel revolution is still one wheel revolution no matter where the
sensor and magnet are. However, the placement of the sensor/magnet has
nothing to do with accuracy, but with how fast the magnet passes the
sensor. If the magnet passes the sensor too quickly, it may not have time
to register. That's why most instructions I have seen recommend placing
the sensor lower on the fork and closer to the hub.

I have used Cateye and Planet Bike computers and both of them work over a
fairly wide range of positions. The Cateye magnet is very small and
light. I even bought spares for my Planet Bike computers for that reason.
Bike wheels don't spin fast enough for wheel balance to be much of a
problem.


  #8  
Old May 4th 07, 07:43 PM posted to rec.bicycles.tech
Lou Holtman
external usenet poster
 
Posts: 627
Default New Computer Installation

Yme wrote:
On Fri, 04 May 2007 07:46:00 -0400, Barnard Frederick wrote:

If we know the distance and the amount of time it took to
travel that distance, we can calculate the speed. So the
sensor can be place anywhere on the fork with out compromising
speed or distance traveled. Makes perfect sense know.



That wasn't to hard was it? Put two magnets on your wheel and you go
twice as fast. It's that easy. ;-)

Lou
  #9  
Old May 5th 07, 12:16 AM posted to rec.bicycles.tech
A Muzi
external usenet poster
 
Posts: 4,551
Default New Computer Installation

says...
I have recently purchased a new CatEye computer for my bike. In the past
the computer that I have installed stated in the instructions that the
magnet should be placed as close to the axle as possible. With my new
computer the sensor/magnet is placed about midway on the fork. Nothing
in the instructions state how high or low on the fork the sensor should
go. If the sensor is placed at a random height, won't this throw off the
accuracy of the computer? If the magnet is not placed as close to the
axle as possible, won't this throw off the balance of the wheel?

One wheel revolution is still one wheel revolution no matter where the
sensor and magnet are. However, the placement of the sensor/magnet has
nothing to do with accuracy, but with how fast the magnet passes the
sensor. If the magnet passes the sensor too quickly, it may not have time
to register. That's why most instructions I have seen recommend placing
the sensor lower on the fork and closer to the hub.

I have used Cateye and Planet Bike computers and both of them work over a
fairly wide range of positions. The Cateye magnet is very small and
light. I even bought spares for my Planet Bike computers for that reason.
Bike wheels don't spin fast enough for wheel balance to be much of a
problem.


Barnard Frederick [Yme ] wrote:
So the computer sensor counts the number of revolutions, this along
with the wheel size is used to determine the distance traveled.
This is similar to how a pedometer works. How does the computer
determine the speed? I would assume how frequent the magnet passes
the sensor. The speedometer would indicate a faster speed when sensor
is closer to the axle, than when the sensor is faster away from the axle.
It seems if the sensor is an inch too high or too low on the fork the
speedometer would be off by less the 1 mile per hour probably less.
This make sense now thanks for everyones explanation.


The sensor increments "one iteration" to the chip- it matters not where
the magnet is placed, it's still "one iteration". The chip has a
crystal clock and a factor for wheel travel. That number may be
adjusted to the actual travel of your wheel with you on your actual bike.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
  #10  
Old May 5th 07, 07:07 AM posted to rec.bicycles.tech
Sir Ridesalot
external usenet poster
 
Posts: 5,270
Default New Computer Installation

On May 3, 2:48 pm, Yme wrote:
I have recently purchased a new CatEye computer for my bike.
In the past the computer that I have installed stated in the
instructions that the magnet should be placed as close to the
axle as possible. With my new computer the sensor/magnet is
placed about midway on the fork. Nothing in the instructions
state how high or low on the fork the sensor should go. If
the sensor is placed at a random height, won't this throw
off the accuracy of the computer? If the magnet is not
placed as close to the axle as possible, won't this throw
off the balance of the wheel?



Hi there.

Is your computer wireless?

If your computer is wireless then higher on the fork the sensor/
transmitter is the better. This is due to the limited distance the
transmitter can cover. My wireless transmitter is limited to 68 cm or
about 7 inches. Many times erratic readings on a wireless computer can
be elimininated by moving the sensor/transmitter as high on the fork
as possible. The magnet can be attached to a spoke nipple.

Cheers from Peter

 




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