Road Bike Guy

I'm looking for a basic altimeter to use while riding. I don't need any other functions because I already have a computer with HR, cadence, etc. All I need from the altimeter is total ascent, total descent, and maybe max altitude achieved.

Does anyone have experience with the Casio Pathfinder or G-Shock watches? How accurate are they? Any other affordable options out there?

johnny99

Casio watch altimeters do a pretty good job at telling you the current altitude, as long as you calibrate the altimeter in the morning. I don't know how well they work for cumulative elevation gain.

Busta Quad

If you want total altitude gain, you're probably going to need a computer. I use the VDO MC 1.0 - works well.

valygrl

But it doesn't have cumulative descending, which is annoying. Only one I can find with both is the Garmin line and maybe a really expensive Sigma Sport (can't remember model).

I miss my old Ciclosport cm434, that was da bomb.

Busta Quad

Why would you want it?

patentcad

My VDO 1.0 seems to overestimate the amount of accumulated vertical feet during a ride. But it does give you accurate gradient % and altitude readings.

Busta Quad

I have (3) and they are all pretty consistent.

Maybe you just underestimate your climbing prowess.

NealH

You can get a Garmin 305 pretty cheap these days. A refurb from Garmin direct will cost you about $190 and, its pretty darn accurate in addition to being self calibrating. The other functions are icing on the cake. You want good elevation data, its a no brainer.

Jynx

if you start and stop your ride from the same spot it dosnt matter. Not sure how many rides you go on where you start somehwere and end somewhere else. Most rides start and stop from your house or where you parked.

valygrl

I actually do quite a lot of riding where I start and stop at different points - in the form of long distance bike tours. You can calculate it at the end of the day, but only if you remember to write down the starting elevation.

Just to keep track, in the above situation, and also, on long hard rides, if you are descending some huge hill into somewhere you have to ride out of, it's nice to know what you have ahead of you, to tune how far you go.

valygrl

Except, you have to charge the Garmin every day, which can be irritating, depending on your access to a power source.

NYJayhawk

Suunto Vector watch. About $150. Compared to my 705 I get very similar readings.

invwnut

wouldn't you need to make adjustments for your elevation too? I seem to recall with some environmental work that required an altimeter reading, isn't there a correction calculation?

patentcad

No, I really think it overstates the accumulated vertical feet by 20%+. On the other hand my watch does the same thing, so maybe my perceptions are warped. My thinking certainly is.

NYJayhawk

All altimeters work based on air pressure (barometer). As a result, all altimeters need to be calibrated somehow to account for weather changes. This is pretty easy to do with most, especially if your rides start and stop at the same place (like your house). Either that, or go to google earth or any other mapping program and you can get the elevation at your starting point.

Garmin's 705 uses GPS altitude (fairly innacurate, BTW) to calibrate. They compensate for the inherent inaccuracy of GPS altitude by recalibrating every 15 minutes or so. Theoretically, multiple "errors" in calibration will balance each other out.

Then you need to figure out how each altimeter accumulates climbing/descending data. My Suunto takes a reading every 20 seconds, and calculates to an accuracy of 10 feet. So if I'm more than 10' higher or lower than where I was 20 seconds previously, it tallies the difference. I had an Avocet unit that worked similarly, but it didn't calculate based on time. It worked on 10 foot increments, so any rise/fall under 10' wouldn't get picked up, but EVERY 10' difference would register. To point out the difference, on my Avocet, if I climbed 10', fell 10' and reclimbed 10' in 20 seonds, it would register 20' of climbing, and 10' of descending. On my Suunto, if all of this happened within one 20 second time gap, it would register a 10' climb with no descent.

Garmin works a little differently, but it's similar to the Suunto method. The Garmin leaves a "breadcrumb trail" of data on your ride. At each data point it records a snapshot of all the data. So at point A, it'll say I was doing 20mph, HR 160, and elevation of 200'. At point B, I'm doing 22mph, HR 159, elevation 195'. Garmin then adds up all these data points.

One other note on calibration: some people feel like a weather change will make the data screwy...and it will to a minor extent. Still, unless a major weather front moves through (in which case you'd have to ride from sunny weather to severe thunderstorms) it won't make a HUGE difference. Example: most mornings my Suunto will read anywhere from -200 feet to +300 feet in elevation (my house is at 120 feet). So if you consider a 500 foot swing the "extremes", and you're out on a 50 mile ride with 3000 feet of climbing, you're going to get a reading that's +/- 500 feet accurate...and unless the weather REALLY changes a lot in a hurry, it'll be much less. On most rides of 2-4 hours, my elevation at my start/end point is within 50'.

Wierd note on the Garmin: if you use Garmin's training center program, it pulls elevation directly off the unit (pretty accurate). If, however, you use Garmin Connect (web based program) it appears to use "map" GPS...elevation based on topo maps with your route overlayed. Map GPS is a whole 'nuther ball of wax....i.e. if you go to MapMyRide or BikeRouteToaster, you get drastically different elevation totals on the same ride (BRT is more accurate if you ask me). This has to do with how the computer calculates topo maps....not what the actual unit is reading.

Finally, you need to get a grip on the fact that NO method is perfect, and that trying to find one is a futile effort. For example, if you want EXACT data on climbing, you'd want your altimeter to measure the smallest elevation changes. Here's why that's bad: let's say you're on a "flat" road for 50 miles, but along that "flat" road, the elevation goes up 1 foot every 10th of a mile and then back down 1 foot every 10th of a mile. To the eye, you're riding a flat road. With precise altitude measurement, however, you climbed 500' (10 feet every mile x 50 miles). So "exact" is a bad thing. On the other end of the spectrum, if you ride the same 50 miles, but it's rolling hills that are all 40-50' tall. No, it's not the Alps, but dozens of "rollers" do add up and should "count". If your altimeter only registers climbs of 50' or more, you just had a flat ride.

So with this last little bit of data in mind, the best thing is to pick ONE tool and one mapping solution, and stick with it. Who cares if one guy says you did 6000' of climbing and another guy said it was 5500'? As long as you keep YOUR method consistent, you can compare across rides, and judge which rides YOU do have the most/least feet of climbing.

Road Bike Guy

Cumulative descent isn't a huge thing for me. I guess my main objective is to find something that is compact and fairly accurate. I don't want something as big as a Garmin on my bike. If that is my only choice I'll probably go without the altitude info.

I'll take a look at the VDO and Suunto.

NYJayhawk

Cumulative ascent and cumulative descent should be equal if the weather doesn't change and you start/end in the same place. I think they all measure it. It's actually a good number to have if the weather does change. If you climbed 3000 feet and descended 2800 feet and started/stopped in the same place, you can average the two together and call it a 2900 foot ride and be done with it.

One nice thing about my Suunto (and others I'm sure) is an altitude alarm. Let's say you're doing a ride and halfway through you hit your highest point at 5000'. Set the altitude alarm for 4990' or 5000', and once the alarm goes off, you know that you're at the top of the ride. Kind of handy when you're in one of those "how much longer can this climb possibly go on" modes. Hearing the alarm go off is a nice morale booster.

dark13star

If you want accuracy, you should really get something with GPS and barometric altitude readings. GPS is generally only +/- 100' for a given point which can lead to a significant cumulative error. However, barometric altimeters are really susceptible to changes in weather, especially mountain weather. A low pressure system can give you 1000' over a few hours.

A 305 would replace your existing device and give you a single device with everything you need.

Busta Quad

Not true unless you need accurate (current) altitude. If all you need is alt gain/avg climb/max climb there is no need to calibrate.

Road Bike Guy

Unfortunately, until Garmin adds a power meter I won't be replacing my Powertap. I've heard rumors that they might add a power meter but as far as I know, it's not available.

dark13star

Ahh, you didn't say that above. I assume you don't have an Ant + Powertap. They work with the Garmin 705.

I stand by the rest of what I said, but it depends on how much accuracy you want. I am not so concerned for cycling, but I am for mountaineering. I once sat in camp at 13,000' with a barometric altimieter and watched us gain 900' of altitude in less than an hour as the weather changed. There is a difference in whether that messes your stats or messes with your life. For cycling, it is probably the former.

NYJayhawk

Planes use barometric altimeters because they're more accurate. Of course, the pilot can get the accurate sea level barometer reading from the air traffic folks at any time, so recalibration is easy.

1000' difference is pretty extreme (I've never seen that much on any altimeter I've owned). I'm not saying it isn't possible, but the accompanying weather change would be drastic enough (i.e. going from a beautiful day to severe thunderstorms) that worrying about the accuracy of your alt reading would be secondary to surviving the trip home. If you made it through the accompanying hurricane you'd experience, you could go to your favorite mapping tool on the internet and get a reading after the fact.

Also, if you know your elevation at certain points (i.e. sign on the road at the peak of a mountain), it takes about 2 seconds to recalibrate your baro altimeter if it's that important to you.

As a general rule of thumb, each .1 inch of mercury is equal to about 100' of elevation gain. On my mantle, I have an old-school barometer that has a range from 28.5 to 31.5 inches of mercury. So if my barometer swung completely from one end to the other, it would equal a 3000' elevation error. Hurricane Katrina got down to about 26.98 inches of mercury, and 30" is the midpoint between high and low. So if you were riding when Katrina made landfall (oh...and were riding many hours in advance before the baraometer STARTED to drop) you'd have had a 3000' error. So again, 1000' is clearly possible, but it also represents a pretty significant weather change, especially if your typical ride is 4 hours or less.

Or just buy a 305.

tkehler

Probably he does. No, wait, you said underestimate. Nope, with Pcad that's just not possible.

NYJayhawk

Valid point. However, I do believe that on the extreme ends of things, the accuracy gets a little wonky. Temperatures can also mess things up a little. But yeah, if you're starting at a reading of 100 feet or 1000 feet and end up at 200 feet or 1200 feet you've still climbed 200 feet.

RoboCheme

I use a Highgear altimeter watch and it's pretty accurate. The most that I've seen it change after a three hour ride starting, while starting and stopping at the same point is about 40'.

One thing to note about barometric altimeters is that you can be standing still and they will note an elevation gain. This is because the pressure is going up and down slightly and everytime it drops a little bit, it will show that as an elevation gain. In other words, you can be riding on a perfectly flat road and see a elevation gain.