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Old 04-06-03, 02:25 AM   #1
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Cyclo-Computer with Altimeter.

Hi,

I am looking for a quality cyclo-computer (not heart monitor) with a relatively accurate altimeter build in. I have read around and the Cat-Eye AT100 seems to do the trick but some complain of its inaccuracy. I gather they all work on atmospheric pressure and hence they all suffer and the best way around it is to re-calibrate it each day. (no problem)

Any idea's out there?

Thanks
Mat

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Old 04-06-03, 02:40 AM   #2
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i have owned 4 of them: the Specialized ? Pro, the Cateye and 2 Ciclos.

the Ciclo is by far the best and is basically as accurate as my expensive Sunnto mountaineering altimeter, but they're not cheap (the C414M w/o computer is about $100 (not so sure) & w/ computer connection is about $150, the HAC4 with HR monitor is around $200 - and this is in Germany so could be more in the US - not sure?)

the Specialized was my first and i found it pretty accurate.

i also have the Cateye and after having had the Specialized and now the 2 Ciclos, i use it only on my commuter bike and rarely use the alti function. the alti is very inaccurate compared to the others. most of the time is is basically useless - almost just a novelty to have it displacyed.

with the Cateye i have 3 problems:
1) it is somewhat inaccurate meaning at the end of a 500m climb it may say anything from 410 to 590m difference in elevation.
2) the ACCUMULATED vertical is REALLY wrong. both the Ciclo and Specialized to an amazing job - i.e. ride up and down and the amount is a) the same for different computers for the same route time and again and b) usually matches with what i expect from a map. the Cateye sometime will say i've climbed 3000m when i've climbed more like 400 - i know what the difference between 3000 and 400 feel like!
3) from day to day it always gets funky readings. yes, the barometric pressure changes every day, but not THAT much. one time it was 100m too low EVERY day for 2 weeks - it's just not possible that the pressure rises that much every day.

anyway, i think the Cateye is fine for speed and other stuff and i like their bike computers, but the altimeter is just too inaccurate. if you just want to have a basic rough estimate, then it is fine. if you really want to know the accurate elevation and/or want to track vertical climbed or descended, don't buy it.

not sure if you can get them in the US easily as they come from Germany, but the Ciclos are the best. i was also satisfied with the Specialized (before i had the Ciclos).

if you can find it, i'd recommend the Ciclo C414M - either w/ or w/o the computer connection. it has a wireless sender which works well, the only problem is the 2 batteries in the sender/receiver must be replaces about every 16 months or so...
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Old 04-06-03, 06:20 AM   #3
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Maybe a GPS like this one:Garmin eTrex Summit

Navigation Features

Waypoints/Icons: 500 with name and graphic symbol

Tracks: Automatic track log; 10 saved tracks let you retrace your path in both directions

Route: 20 reversible routes with up to 50 waypoints (available only by the free update offered on this website)

Trip computer: Current speed, average speed, time of sunrise/sunset, resetable maximum speed, trip timer, and trip distance

Map datums: More than 100

Position format: Lat/Lon, UTM/UPS, Maidenhead, MGRS and other grids

Electronic compass features

Accuracy: ±2 degrees with proper calibration (typical); ±5 degrees in extreme northern and southern latitudes

Resolution: 1 degree

Barometric altimeter features

Accuracy: 10 feet with proper calibration (user and/or automatic calibration)

Resolution: 1 foot

Range: -2,000 to 30,000 feet

Elevation computer: Current elevation, resetable minimum and maximum elevation, ascent/descent rate, total ascent/descent, average and maximum ascent/descent rate

Pressure: Local pressure (mbar/inches HG), 12-hour automatic pressure trend recording


Performance

Receiver: Differential-ready, 12 parallel channel GPS receiver continuously tracks and uses up to 12 satellites to compute and update your position

Acquisition Times:

Warm: approx. 15 seconds
Cold: approx. 45 seconds
AutoLocate™: approx. 5 minutes
Update Rate: 1 second, continuous

Accuracy:

Position: 15 meters (49 feet) RMS

Velocity: 0.1 knot RMS steady state

Dynamics: 6g's

Interfaces: RS232 with NMEA 0183, RTCM 104 DGPS data format and proprietary Garmin

Antenna: Built-in patch

Physical Size: 4.4"H x 2.0"W x 1.2"D (11.2 x 5.1 x 3.0 cm)

Weight: 5.3 ounces (150 g) with batteries

Display: 2.1"H x 1.1"W (5.4 x 2.7 cm) high-contrast LCD with bright backlighting

Case: Waterproof to IEC 529 IPX7 standards

Temperature range: 5°F to 158°F (-15°C to 70°C)

Data storage: Indefinite; no memory battery required

Power Source: 2 AA batteries (not included)

Battery Life: Up to 16 hours (typical use)


Plus all the other neat stuff a GPS can be used for off the bike. If you are a gadget geek, it's the way to go!
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Old 04-06-03, 07:48 AM   #4
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Hi,
Altimeters that rely on air pressure are a joke. Get a nice computer, and if you really want an altimeter, get a GPS one.
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Old 04-06-03, 09:06 AM   #5
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Regarding bicycle computers with altimeter and inclinometer functions....

1. In addition to a SigmaSports BC1200 with Cadence that uses wired pick-ups
on both tandems, Debbie has an Avocet Vertech II that she attaches to her
handlebars to keep track of our ascents, descents, and the weather:
http://www.avocet.com/vertechpages/vertechalpin.html

2. Always being curious about the grade of various climbs I came across the
wireless CicloMaster CM414 Alti last year and it has proven to be a really
neat computer that provides many useful features -- like an adjustable trip
odometer and forward/backward scrolling -- and more data capture and logging
features than I've ever seen available from a bicycle computer:
http://tinyurl.com/6ap (or go right to the CM414 by visiting:
http://www.ciclosport.de/eng/html/katalog/cm414a.htm) It runs off a wireless
pick-up from the front wheel of our tandems.

3. I recently tried out the Specialized Speed Zone Pro Classic and while it
too provided percent grade and vertical feet gained along with most other
cyclo-computer functions, it was hard to scroll through the data while you
were on the bike and offered no where near as many other features that were
available from the Ciclosport. http://tinyurl.com/6apm

Summary:

The CicloMaster CM414 Alti is really slick, very accurate and has more ways
to look at data than anyone needs; I love it. It's bit on the pricey side,
comes with a wireless transmitter and accessories are also bit on the
expensive side. Altimeter function is accurate but altitude gained will
seem to come up a bit short due to the way the computer collects the data,
i.e., sampling rate will result in minor gains and losses being ignored.
However, you'll get credit and see all your "Max" effort data at the end of
the ride. You really need to read the instructions carefully. Don't have
the PC interface or software for post-ride analysis so I can't comment on
it.

The Specialized Speed Zone Pro Classic at $99 comes up short on features and
usability. You must scroll through 12 functions to see what you want and if
you miss something, go around again. Altimeter doesn't record descents, nor
does it capture max, etc... Same with inclinometer: shows real-time (and is
a bit generous compared to CicloMaster) but does not capture max up, max down
or average. Made by same company as CicloMaster and uses the same wireless
pick-up (in fact, I ran both the Ciclosport & Speed Zone computers off of
the CicloMaster's pick-up at the same time). After conducting my
side-by-side comparison I sent the Speed Zone back to Specialized.

The Vertech II is not a cycling computer; rather, it was designed for
mountain climbers, skiers and hikers. It is the most accurate of the three
altimeters but subject to errors/needs recalibration as the barometric
pressure changes. However, the altimeter functions are really nice and,
when used in conjunction with a regular cyclo-computer it gives you some
other interesting data to use.

If I could only have one, it would be the CicloMaster. However, since I
already had the Vertech II and the SigmaSports computers it's really nice to
have all three. The SigmaSports is hardwired to the rear wheel and has
different re-set features than the CicloMaster which is nice, plus it allows
Debbie to watch our cadence. The Vertech has allowed Debbie to keep an eye
on our altitude, vert. feet gained and although it doesn't have an
inclinometer to tell her what the grade it it does indicate if we are
gaining or losing altitude. The Vertech's altimeter function also allows me
to sanity check the CicloMaster's current altitude (they both seem to stay in
sync. even when the weather changes).

Bottom Line: The altimeter functions are not precise in the truest sense of the word. However, the "vert. feet gained" is what most folks are interested in and any of these devices will give you that data. If it's off by 10% (+/-) it'll always be off by 10% (+/-) so they will still provide you with relatively comparable data for different rides, i.e.,Joe's Mountain Ride netted you 5,600 vert feet and Col de Bubba netted your 7,600 vert. and the difference was an approximate difference of 2,000 vert ft.

If you want something more accurate than that get a compact GPS unit.

Last edited by livngood; 04-06-03 at 09:12 AM.
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Old 04-06-03, 09:16 AM   #6
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I would echo my dissatisfaction with the Cat Eye.

However, on given day with "stable" air, it will repeat a given measurement....

Can anyone explain the relationship of air pressure to a given altitude setting?

For instance: at sea level, how much altitude deviation would there be with the atmosphere at 28.5 or 32.5 millibars?

Would the differences be amplified at higher elevation?

current pressure is 30.0millibars against known altitude of 5,000ft.
what happens if it changes to 28.0 or 32.0

Is the deviation larger at higher altitude...?
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Old 04-06-03, 11:43 AM   #7
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Quote:
Hi,
Altimeters that rely on air pressure are a joke. Get a nice computer, and if you really want an altimeter, get a GPS one.
i disagree. i am an avid mountaineer and a quality barometric-measuring altimeter is a great thing.

i also own a GPS unit (Garmin etrex) and for basic cycling it is not so good --- it is much larger, weighs more AND it uses a set of batteries in a day tour. also the GPS can loose signal in the mountains or forest, particularly with altitude readnig which requires a strong signal to ne accurate.

as long as you know how to use it (e.g. setting the elevation from a known point every day and being aware of effects during storms and chaging weather) my Ciclo altimeter is VERY accurate.

also, a good cycle computer w/ altimeter still costs less than half of what a GPS costs --- plus it also sums your bike milage, total vertical climbed, etc. and it stays on the bike handlebar, ready for every tour with battieries that last over a year!
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Old 04-06-03, 11:47 AM   #8
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First of all, the vast majority of aircraft altimeters use air pressure to measure the altitude, so I wouldn't necessarily say they are a joke. They MUST be reset to the current atmospheric pressure (altimeter setting) to be useful. It isn't unusual for the pressure to change substantially from one day to the next. Those are the highs and lows you see on the weather map, high and low pressure areas which move across the country.

In the U.S. and Canada, we use "inches of Mercury" (" Hg) as the unit to measure barometric pressure in the aviation world. (In Canada we now use kilopascals for non aviation use, which are related to millibars, as a metric measurement of atmospheric pressure). A change of one inch of pressure equals 1,000 ft. I think in the above post where you mention millibars(Mb) you may be confusing it with inches of mercury as the equivalent millibar setting for 30.00 " Hg, would be 1015.9 millibars.

A change from 30.00 "Hg to 28.00 "Hg would be 2000 ft., which would be very unusual. It's common, however for the change to be enough to cause an error of for example 500' over a day if the weather is changing rapidly. The pressure overnight can be substantial if you've had a storm pass through and could be 1,000 feet in error if you don't recalibrate the altimeter, which pilots do periodically as they fly across the country, at low altitudes. At airline type altitudes (above 18,000') all altimeters are set to a common setting, so they will all be the same, and then they are reset to the local setting as the aircraft descends through that altitude nearing their destination, with the local altimeter setting.

As you can see this altimeter business can be fairly complicated if you want a really accurate reading. Even GPS altitudes can be in error depending on how the GPS is set and the satellites it is picking up.
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Old 04-06-03, 11:49 AM   #9
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i agree with livngood's post.

the Specialized Pro and the Ciclo CM414M are the ones i wrote about, and i also agree that both are good, but the Ciclo better and IF you also want the integreated HR monitor and computer download, the HAC4 is awesome! i also agree that for MTBing the "vertical gained" is the most important thing (not so for mountaineering) and in this respect, my Ciclo is MORE accurate than my $250 Sunnto precision mountaineering altimeter.

the computer interface is great for both for tracking tours and reports all kinds of stats like vert gained/lost, min/max, avg speed, % incline, temperature, etc.
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Old 04-06-03, 01:04 PM   #10
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Interesting,
I had an altimeter watch, not expensive, sounds like the Ciclo is of better construction. Another possible difference is that my part of the world is a spot where the weather likes to change a lot. After I had approaching fronts make hash of the alimeter readings a few times, I came to the conclusion it was a joke.
Around here, I wouldn't bother, but it's good to know it works out for some.
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Old 04-07-03, 08:49 PM   #11
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Thanks for the info, yes I did forget the difference in expressing millibars and inches of Mercury. I had never heard about the "1000" ft to 1inch ratio.

In any case, (aneroid barometers) or altimeters do suffers from artificial as well as natural variations in air pressure. I think the cateye may suffer from "artificial pressure "fronts"" that develop when cycling on "unsettled" gusty-windy days. The same device may work much better when strapped to a wrist of a person at walkspeed.......
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Old 04-08-03, 07:24 AM   #12
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Hi guys,
Thanks for your responses. I have certainly givent he Cat-eye the flick and I am tossing up between the Ciclomaster CM414 and the Specialized Speedzone Pro. The major drawback for me with the Specialized unit is it resets after 10 hours and I can foresee days where I will be riding for longer than that. (maybe not continuously but if I start at 7am I could still be riding after 5pm and I dont want to loose my data)

That drawback aside the Specialized unit has a inclometer feature which I dont think the CM414 has. This is appealing as I will be doing a lot of mountain work.

I am tending towards the CM414 simply as is doesn't reset after 10 hours.

Does anyone a retailer who will ship to Australia??

Thanks
Mat
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Old 04-08-03, 08:00 AM   #13
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Quote:
That drawback aside the Specialized unit has a inclometer feature which I dont think the CM414 has. This is appealing as I will be doing a lot of mountain work.
the Ciclo does have an inclometer. it displays 2 pieces of data:
* % grade
* current vertical change rate per hour (i think it's per hour rather than per minute although it's based on the last minute or so)

actually, you can download the complete Ciclo user manuals in PDF from from the web - go to http://www.ciclosport.de/, click on Enter for English, then Manuals

i think the CM414 stores 60 hours of data - it's long enough that last year i stopped it at the end of the day it lasted for my 8-day TransAlp trip.

if you get the computer connection, then the %grade is also included in the available data for graphing.
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Old 04-08-03, 11:45 AM   #14
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The suggestion to get a GPS is valid since it will give you altitude, max speed, av speed, and distance all. BTW there is nothing wrong with pressure altimiters.
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Old 04-08-03, 01:03 PM   #15
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On this occasion I have settled on a cycle computer as I want it on the handlebars...the GPS sound good though. Plus I need a new Cycle computer anyway!

It appears the CM414 is a discontinued line and is replaced with the CM434. I can get it for US$102.77, cadence kit for US$15.09 and postage from France is US$11.34 from xxcycle.com.

Does anyone know of a better price? Thanks.

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Old 04-08-03, 03:01 PM   #16
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Garmin offers a handlebar mount. The information it collects coupled with ability to download info to my PC would cause me to give up my cycle computer completely if my GPS had cadence.

The only other drawback is Max. Speed is iffy, I hit 51.3 MPH while walking to get a cup of coffee Saturday morning, but I don't log Max. Speed anyway.
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Old 04-08-03, 04:17 PM   #17
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I have the CM414 that is downloadable into the PC. I think the download features are great. I rarely look at the numbers going by me when riding now since I know I will ahve them when I get home. You can also mark certain points in your ride and then lable the points on the computer for future reference. The guys that ride the same roads as me really like my computer so they know the grades and elevations we have gone through.

Here is a screen capture of my last weekend ride.

CM414 is great as far as I am concerned. Sometimes I wish I would got the one with the HRM in it. Oh well, it is nice to have an HRM off the bike (ie running).
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Old 04-08-03, 11:07 PM   #18
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Quote:
Originally posted by late
Hi,
Altimeters that rely on air pressure are a joke. Get a nice computer, and if you really want an altimeter, get a GPS one.
Things are slightly different then this, if you calibrate a quality air pressure meter as often as you can, the accuracy is set between 5 to 20 meter.
A GPS however requires at least 3 sattelites for the longtitude/latitude and one for the altitude.
Because there`s only one signal for height, accuracy is set between 20 and 100 meter.
This is the reason you see a lot of alpinists/ mountaineers with air pressure meters, rather than a GPS, their accuracy is far more better.


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Old 03-17-04, 09:59 AM   #19
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Has anybody tried the VDO MC1.0 :

http://www.pezcyclingnews.com/?pg=fullstory&id=1955
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Old 03-17-04, 10:02 PM   #20
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Has anyone tried the Vetta V100A?
I can't seem to find many reviews on it.
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Old 03-18-04, 08:10 AM   #21
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Several decades a go I used a German temperature-compensated mechanical type altimeter to help navigate in the mountains for backpacking. I would calibrate it when I knew were I was on the topo. It was really very accurate. Better than a compass when you are in the trees. Many GPS units have an air-pressure type altimeter because of the poor altitude resolution of GPS. However, the new WAAS mode might be accurate. I understand that it will eventually be used for auto-pilot takeoff and landing of aircraft. If true, it might have very good altitude accuracy.

Today, I would calibrate my altimeter with a NOAA radio receiver. I found once a day was adequate.

As already commented, you do get GPS drop-outs in the trees, mountains and I would add, among tall buildings. But that's not too bad unless you are trying to generate/record a track. The benefit of a topo road map might make a GPS worth while. I think one of the new Garmins will give you the map ($100 extra), WAAS and 24 hours on two AA batteries. Not bad.

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Old 03-18-04, 02:51 PM   #22
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I have a wireless Vetta V100A with wireless cadence. So far I have really liked it. I put about 500 miles on it last summer and fall, but I haven't yet had a chance tp try out the altitude feature, since almost all of that riding was on flat roads. I'll be testing out the altitude functions later this summer.
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