I am fairly new to bike computers, I never had one when I did mountain biking back in the 1990's.
I bought a Sigma wireless one earlier this year, but the battery went flat and it lost all the stored settings, which was a bit of a downer.
So today I went back to the LBS and they recommended a GPS one, in fact the Garmin Edge 200 which barely cost any more than the Sigma.
But there's a more expensive version, the 500, which looks the same but comes with a heart rate monitor that you put round your waist.
Of course the LBS were recommending I bought this one if I could stretch to the extra £100 it cost (about $150 extra)
Now I have gone from just wanting to know my speed and distance, to computers that tell your heart rate.
So I came away from the LBS confused, with nothing.
Do I need to know this. I mean, my heart rate while I am on a ride? I'm 50 and only ride for fun, I'm not trying to win any competitions.
There's a whole forum for these kinds of discussions.
GPS, HRM and Bike Computer
GPS bike computers are very nice. Nobody really needs one. But whether it would be useful to you depends on your goals for riding. A HRM is useful for anyone who is interested in improving their fitness, or anyone with a history of health issues who needs to keep track of their HR. Using a HRM helps you to ride at a specific intensity, which is beneficial for developing fitness. If you don't care about your fitness at that level of detail, that's fine. The HRM is not the only difference between the Edge 500 and 200.
Frankly, I can't recommend the 200 for anything other than road riding where you tend to have long, straight-ish segments and well defined turns. The Edge 200 only allows for a single recording interval, which records your position at a variable interval. That works fine when your route tends to be fairly straight with defined turns. But on a really twisty mtb trail, that recording interval sucks. All of Garmin's receiver's can do that method, and I've used it on several different models. I have never found it to be worth a damn on the mtb. Fine for hiking, fine for road riding. Crap for mtb. When I am on my mtb, I will ONLY use 1sec recording. That option tends to only be available on the nicer models with other features, as well.
Ignoring all the other differences for now, that single feature would get me to spend the extra over the Edge 200 every time. However, it's not your only option. You can look for old Edge 205/305's (discontinued but still available as refurbs or used), Edge 605/705's, Forerunners (205/305/310XT, etc), a handheld (eTrex 10/20/30, Oregon 400/450, Dakota 10/20/30, etc). In fact, a handheld like the eTrex 10 or 20 would save you quite a bit over an Edge 500, and the 20 would have more general features (fewer fitness features, though). Bike shops don't tend to sell handhelds, though.
I have two GPS receivers. I have a Forerunner 310XT that I use sometimes. Usually when I know the trails I'm visiting and just want to record. It's small and gives me the basic information I need on the screen. Other times, I'll use my Oregon 450. It's a full-featured mapping GPS. I use it when I'm visiting a trail I don't know, when I'm scouting for new trails, and when I'm out hiking and documenting maintenance needs. I sold an Edge 705 and bought a Forerunner 205 (I upgraded it after a couple years to the Forerunner 310XT) and the Oregon 450 with the money, if that gives you any idea about the relative costs.
maybe you are already aware, but
if you own a smart phone (and who doesn't?) you probably already have the most sophisticated bike computer available. I have an iBike stem mount for my iPhone 4S. Topeak has the app (free!) which I use most often. iBike has a free one too. It tracks time, total elevation, avg speed, max speed, GPS for both "map" type tracking, or a Google Earth map. It stores all your trips so it is very easy to race against yourself over a specific trip. You need to purchase a heart-beat sensor and a chain-stay sensor if cadence and bpm is important to you. Both are also available from Topeak. The iBike mount also has an additional battery that allows you to keep your iPhone on continually, even during a six hour ride. I really can't imagine the need to buy a $3-500 computer just to let it sit on your bike
2014 Marin Nail Trail 29er
A simple bike computer driven by a magnet on the front wheel is the most accurate and trouble-free way to go. I have a Cateye Strava wireless I got for around $60. It is auto-off and on, so it is totally hassle-free.
They do lose the trip and odometer info when the battery dies. However, if you know what it is, you can reenter it. Your Sigma probably supports this too -- I think they all do. I record the odometer reading every so often, and trip distance after every ride, so when it dies I can figure what to set the odometer to. Or I could just replace the battery every year. At any rate, I wouldn't trust any device with my ride stats.
There are Cateye models with HRM if you are interested in that. However, I have a separate HRM with a chest strap and wrist readout. I see no need to complicate the computer with this feature and vice versa. HRM is great for road bikers, but I haven't found it too useful for mountain biking. You really don't have that much control over your heart rate unless you have a lot of long climbs that aren't too steep. Around here, it is either downhill or flat, where the curves in the trail limit your speed and heart rate, or you have short steep climbs. You can go fast or slow up the climbs if they aren't too steep, but by the time you get your heart rate stabilized where you want it, you are at the top.
I monitor my effort by watching how hard I am breathing. If you can still talk, you are running at a sustainable level. Over that, it is just a matter of time until your body will have to slow down. Like a gasoline engine -- the limiting factor on power is how much air you can get thru the thing.
I also use my Android smart phone and use Strava or Runkeeper, and as Time229er says, there are free apps that are more like a traditional bike computer. However, they are very inaccurate when mountain biking, sometimes shortchanging me as much as mile in six. I just like to see where I have ridden on a map, and will sometimes save a copy of the map in my records. I just start it recording, and throw it in my CamelBak (protected in a bubble-wrap envelope).
If you have a smartphone you can use it, but do not be deceived. It is not the most sophisticated bike computer available. It may look fancy and have a slick interface but out of the box, but the accuracy is NOT the same.
I am a nerd for maps. I like to see where I have been on the map, tracing the contours of the terrain and remembering the features on the trail. That is why I ride with a gps.
Re: Bike computers
Excellent advice in this thread from everyone. Thanks to each for taking the time.
Sent from my XT907 using Tapatalk 2
Yes thanks for the advice everybody.
I do have "Map my ride" on my phone, and it is superb.
But it uses up the phone battery very quickly, both times l have tried using it the phone battery died before the end of a two hour ride.
I have the Garmin Edge 200 on trial at the moment, and it does seem at least as good as a traditional bike computer, without the need for sensors and wires.
The back light can be set to stay on (useful at night) and it seems to refresh every second.
I have not actually tried it on a ride yet, just a walk round to the shops, but l will see how it performs.
The data fields on the edge 200 may refresh every second but don't let that fool you. It absolutely does not save all of that. It uses an algorithm to determine when to save/record data.
Save the .fit file from it and view it on a map. On a twisty mtb trail, accuracy will be shit. You cannot use a road ride to evaluate this gps for mtb use. Road will be fine.
OK so is the Edge 500 better, or does it use the same system?
I can afford the 500 if it is worth it, although my wife says it will have to be my christmas present
Anything with the option to record every second will be better and the Edge 500 is one option. It will also use the same algorithm to conserve memory (it will prob be the default setting out of the box) but you have the option to change it.
The wheel sensor improves accuracy even more.
It's strange -- my Galaxy S3 is within a percent of my Cateye when riding with my wife on a paved, wooded trail in the same park where I mountain bike. It is under heavy canopy cover, and would be considered quite twisty if you were driving it in your car. But I guess it is nowhere as twisty as a typical MTB trail.
Originally Posted by time229er
I've never had battery life issues, and I buy the cheap Chinese three-for-$15 variety batteries. The backlight for the display is the main culprit, so if you have it mounted on your handlebars to watch, yeah, you will need some external power source. But as I said, mine is just along for the ride in my pack, so the display is off unless I get lost.
This is interesting, but has turned out more complex than I thought!
I'm not actually that bothered about accurately mapping every turn I make. I just want something that tells me how fast I am going, and roughly how far I have ridden on my latest ride.
And knowing the time would be useful, and how much climbing I have done.
I am unlikely to regularly download my route and go over it in detail.
I currently have a Sigma wireless computer and my friend has a similar one, but a different make.
Despite setting the wheel size accurately they read about a half mile difference after a ten mile ride.
I will give the Edge 200 a chance on my regular route, which has a fair bit of singletrack, road riding, rough paths, and off road descents under a tree canopy.
I know how far my Sigma thinks it is....10.5 miles. Let's see how the Edge 200 stacks up.
If it's no good I'll take it back and try the Edge 500 (with the refresh rate set to 1 second)
Yeah, who would have thought that bicycling could be such a complicated sport
I use the Av Speed function to track my improvement (or lack thereof!) by comparing to past rides on the same trail. 1/10th mph increase in average speed is significant to me. My phone just won't cut it.
That's 5% error which isn't horrible, but I think it should be better. Is the difference fairly consistent -- i.e. his always reading more than yours? If so, I bet the wheel size is in fact not set accurately. Measure the rolling distance of the tire on a dirt surface, running your usual pressure and carrying your usual weight. I measured 10 revolutions then averaged. In any case, DON'T go by the wheel size chart provided in the manual.
Despite setting the wheel size accurately they read about a half mile difference after a ten mile ride.
I don't know how accurate the climbing data from the phone is. My guess is that it is better than the Dist/Rate/Time stuff because sampling/recording interval isn't going to matter as much since the vertical line you travel going up and down stuff isn't as crooked as the horizontal side-to-side stuff. However, I bet it still short-changes you. Also, GPS is not as accurate vertically as it is horizontally, but if you don't care about your actual altitude, just relative change, it would be better.
Thanks for mentioning this. I sort of lost interest in Strava and haven't been using it much. I will start playing with it again to see how consistent the climb figures are. Unfortunately I haven't been saving them for my past rides.
The more inaccurate a gps is, the less consistent the readings are. That is the definition of accuracy-repeatability. Precision would be how close the measurements are to the actual value. Folks get those mixed up all the time.
A number of people have tried to quantify how close their phones and gps receivers are to actual. It is easier to compare that for a single point so geocachers do it regularly enough.
Figure that a track is just a series of points. Error from each ppoint gets compounded. Every decent gps uses filtering algorithms to try to improve data quality. This is doubly important for phones. They cram a lot more electronics into a smaller space so everything is smaller. The antenna is the important part here. Nowadays, this is the main reason phones are less accurate. So the raw data from the phone is all over the place. Each app is responsible for the data filtering and not every app is equal.
Elevation is a whole other ballgame. For consumer hardware, gps elevation is definitely less accurate than horizontal positioning, and it varies depending on gps reception. You get better vertical accuracy by comparing your track to a digital elevation model (DEM) of the planet. But that still depends on your horizontal position and depending on your local terrain can be very close or way off.
A better elevation measurement comes from a barometric altimeter. This sensor needs to be properly calibrated to a known elevation to be accurate. The better Garmin Edges have an automatic calibration. Handhelds have manual calibration where you set at known elevation
Well, l just did a short six mile loop with the Edge 200.
First impressions are that it's much better than my Sigma wireless one.
The numbers are larger and the display stays lit up so l can see it.
One thing that was a bit confusing though. Although l started and finished at my house, the computer claimed l had climbed 710 feet and descended 760.
The ride starts with a long climb, then a straight bit and a long descent to below my house, finally a climb back up the hill to my house.
Surely the climb/descent figures should be the same?
You've already made the decision, but I'm happy with my Edge 200. All I wanted was something to track miles, speed, etc. w/o a bunch of wires, sensors, and stuff to deal with. I ride 3 different bikes, and I like to have the one computer for all of them. No fuss, no mess. Since the Edge 200 costs about the same as a new wireless computer and a couple extra mounting kits, it was an easy choice for me.
The 200 is accurate enough for my needs -- I have run Strava on my phone and the 200 at the same time, and the results came back very close. The real-time elevation gain on the 200 is way off, but that isn't too important for me on the ride, anyway. I assume it is far more accurate once uploaded to the website, where the track is overlaid on a map.
'11 Specialized Enduro Expert for the trails
'13 Felt Z4 for the road
At the moment l have the Edge 200 on loan from my LBS.
I can go for the 500 if l want it.
After reading the posts above l do need to try it under trees etc to see if it works well enough. It's a good excuse to go for another ride!
I am guessing that the readings on the unit are approximations, and are corrected when/if you download the route to your computer.
As sometimes when l turn it on, it will tell me l have climbed maybe 34 feet by counting up fairly quickly from zero while l am sat there looking at it!
They sorta are approximations. The elevation it reports is calculated based on the best information it has, which is limited at best. Whether corrections are applied depends on where you upload it. Those corrections will still be a loose approximation because they depend on the less accurate "smart" automatic sampling interval.
I will post a couple screenshots later when I get on my computer from two rides I did at a local trail recently. One with smart recording on a 62s (well known for being highly accurate) and one with 1sec recording on a Forerunner 310XT (a much smaller model with a much smaller antenna that is much more accurate because of the sampling interval). Another component to the accuracy wuestion is speed. Going downhill faster tends to result in a less accurate gps track than climbing the same hill. This effect gets exaggerated with smart recording.
Since you didn't buy yet, I wrote up the Sigma Rox 10.0 GPS in the electronics forum here, still quite happy with it. For the money considering it comes with all the sensors, it's a fair price.
Elevations are never particularly accurate on any of these units.
One thing that is particularly nice with the 200 ( and l guess all these GPS units) is the backlight can be set to stay on.
So on a night ride (it goes dark at 4.30pm here now) you can still see it all the time.
It must use battery power, but after two night rides the battery indicator still shows full.
Yes, the backlight is a nice feature. I have gone 4 days commuting with mine (~ 9 hrs of ride time) and my battery indicator was still over 50%. Although I almost never go that long, as I want to download and review the rides!
'11 Specialized Enduro Expert for the trails
'13 Felt Z4 for the road
I did a ten mile off road circuit tonight with the Edge 200.
The unit performed well, it claimed l had done just under 10 miles, where my Sigma (non-GPS) said it was 10.5.
The Garmin struggled under a tree canopy, as others said it might.
The speed was saying 2mph when l was climbing at over twice that amount.
Anyway, l decided to return it and go for the 500, as it is only £50 ($75) more, including a heart rate monitor, and general advice seems to be that it is a better option for MTB use.
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