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What electronic device (if any) do you use to measure your miles?

I've got a 16 year old (I believe I got it when I got my Mamba back in 2000) CatEye Enduro 2 that still works like a charm.

A couple days ago I remembered I have a Garmin 305 'watch' I used for running before I had microfracture knee surgery. Pulled it out, charged it up, and was happy to find it had a Cycling mode on it. Attached it to my bike tonight to compare the accuracy of my Enduro 2 to the Garmin 305.

It was very very close. At the end of my first true ride in probably 7 years I rode for 36:04. The Garmin had me going 5.28 miles and the 16 year old Enduro 2 had me at 5.37 miles. I'm not sure which one was truly correct but I was pretty impressed by how close the two were. Especially with the Enduro being 16 years old...and me being the one who set it up on my bike 16 years ago. When it came to comparing mph both were pretty close most of the time (see more below).

Which one did I prefer? I'd have to give the edge to the Garmin. I will say the Enduro 2 was much easier to see in low light conditions and the change in my speed changed more quickly with it as well. However, when I got back home and was able to load all the data the Garmin 305 recorded I knew it was the one I would go with.

It tracked my entire route (and could play it back to me if I wanted it to), had total miles, total time, average speed, fastest speed, elevation changes, highest/lowest elevation, weather condition, allowed me to type in notes about my ride, and if I would have chose to do so I could have ridden the course several times keeping all the same information for each lap.

I don't really want to remove the CatEye Enduro 2 because of nostalgic reasons, but I'm thinking it may be gone by the weekend :D

TripleB
 

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Please feel free to mail me your Enduro 2 - my absolute all-time favorite cyclecomputer. Small, simple, resettable odometer, long battery life, and wired. Easy to calibrate to wheel circumferance to make it super accurate. Not sure about this, but maybe the Garmin does not consider small movements along the ride, which can add several feet for every mile traveled.
 

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Check out the Planet Bike Protege computer. Wired, only two screens with large numbers, no buttons to push, one watch battery lasts nearly two years. Resets easy. I've got two of them. I think they cost about $30.
 

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maybe the Garmin does not consider small movements along the ride, which can add several feet for every mile traveled.
Dunno about that but they take readings on a timed basis and if you happen to turn a corner it could plot a diagonal line across the corner between two readings. You can even see this on Connect. So if you have lots of corners you could be missing a bit of distance.
 

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A bike computer with a wheel sensor measures distance and speed very accurately, assuming you entered the wheel circumference properly. A GPS unit directly measures only your instantaneous position, with varying degrees of error. It measures distance traveled (and therefore speed) only indirectly, by comparing consecutive position fixes. The position errors cancel out in the long run, but unless you're traveling a straight path, the GPS will under-estimate distance traveled (at least a little), because the calculations assume a straight line between the two fixes, and if you followed a curve you actually traveled a little farther.

So (if you have the right wheel size entered), the Cateye will give a slightly more accurate figure. Very sightly -- the difference you saw was less than 2%.

BTW, the fact that the computer is 16 years old is utterly irrelevant. There's nothing in there that deteriorates with age. As long as it works at all, it should be as accurate as the day you bought it.
 

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I was finding that my Garmin 810 was "off" (short) by about .6 miles over 100, as compared to a Cateye Micro Wireless (non-GPS) that was calibrated to wheel circumference.

Having that degree of accuracy or off by even a mile or two in 100 didn't matter to me. I also recall that my Cateye(s) would on occasion, drop to a speed of 3 or 4 mph from 15, as I was spinning along. Possibly sensor battery going bad. I'm also now using a Garmin speed sensor for greater accuracy of speed when doing paceline riding. Works well and will be useful when mt. biking this fall and winter as they track speed and distance better when in deep woods.

Having the ability to dump the ride statistics to Garmin Connect instantly via BlueTooth thru my iPhone, is a great feature, as opposed to needing to remember to drag my phone out of my back pocket to stop a GPS track being run in the Endomondo app. More then once I drove partway home from a group ride before remembering to stop the track. Avg. speed increased on those rides of course !.

I've been very happy with the 810 and Connect as well, having luck with the unit when many others report crashes, etc.... I also use a Garmin swim watch which counts my swim yardage and dumps that too to Connect. It's a functional system of activity trackers for me.
 

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My garmin seems fairly accurate, i have a speed sensor paired to it so it can hot fix the gps data. Meaning if i go under a bridge or in some deeply wooded path my trace is not lost.

When i am on the trail it seems to track well with pavement markings, meaning every mile seems about on.
 

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My Polar GPS runs short about 1% compared to my wired Cateye Astrale 8.
I looked at the mapping of one Criterium that I did, and my GPS map said that I was taking "short cuts" thru people's yards. Like others have said, it might work fine in a straight line, but doesn't like turns. The speed also lags behind the instantaneous speed of a wired unit.
 

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Discussion Starter · #9 ·
A bike computer with a wheel sensor measures distance and speed very accurately, assuming you entered the wheel circumference properly. A GPS unit directly measures only your instantaneous position, with varying degrees of error. It measures distance traveled (and therefore speed) only indirectly, by comparing consecutive position fixes.
So what I'm hearing is that I should leave both on my bike...one for perfect accuracy and one so I can load a ton of data easily on my computer :thumbsup:

TripleB67
 

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I just use my Android phone and both Polar Beat and Road Bike Pro. (Polar Beat doesn't track climbs, and Road Bike Pro doesn't recognize my Polar H7 heart rate monitor). As for distance, Polar Beat and Road Bike Pro will sometimes match or RBP will show up to 1.5% less distance. RBP has never shown greater distance than Polar Beat. Everything is "downloaded" automatically. I can go out to the Polar web site or runtastic web site and compare rides and see improvement over time. The GPS in the Android phone does eat battery, so I have a small battery pack in my seat bag and I run a charging cable along the top tube to my phone. I'm trying to create a handlebar mount for the battery pack do I can mount it right next to the phone.
 

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A bike computer with a wheel sensor measures distance and speed very accurately, assuming you entered the wheel circumference properly.
This is a big gotcha that people overlook. The problem is the true radius of the wheel will be affected by numerous variables which will lessen the accuracy substantially. Some factors that come to mind: Tire wear and all the factors that change the tire pressure such as daily air loss through the tubes, temperature, and seasonal variation in rider weight/equipment.

For example for a 700c wheel running 23c average tires, just 2mm of tread thickness wear over the life of the tire will change the computer's mile distance error by around 30 feet.

For GPS calculated distance, the two big factors that will affect precision will be the curvyness of the route and the unit's sampling/recording rate. A higher sampling rate by the computer, say once per second, will increase the distance estimation accuracy- at the expense of the computer's memory and battery power.
 

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Sometimes I use the Android Strava app on my phone and sometimes I use my Garmin 500. The phone is easier since I do not need to attach it to the computer to upload and I have it in my jersey pocket anyway. If you want to see numbers as you ride the Garmin would be better as having a phone on your handlebars seems like a poor idea and it would suck up your battery since you would need to have live view on.

Before all the gadgets I just went on a bike ride and put the miles on the calendar and would add them up each week. . That required driving the route one time to get the mileage. It actually worked very well for total miles. New routes required some guess work. I just used what I thought was my usual average speed and multiplied it times hours of riding time.

Back in the day you could then report it to the President and his office would send you a pin for 5000 miles. Nowadays depending on the President they might have you jailed.
 

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I have a cat eye strada on my older bike and haven't bothered to put anything on my newer bike that I ride most of the time now.
I pretty much know how many miles a route I plan will be and confirming or getting a precise number doesn't really do anything for me so I don't think I'll bother getting a computer for the new bike. I do like having a computer on my older bike as that's the bike I use for racing and I gauge my progress with a certain time trial route I do so I like to know average speed for that one route I do like once a month.
 

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So what I'm hearing is that I should leave both on my bike...one for perfect accuracy and one so I can load a ton of data easily on my computer :thumbsup:

TripleB67
Not necessarily. If you want to upload track data and be able to share it and play with it on the computer, do Strava comparisons, etc., you need something like the Garmin. If you have that, you don't really need the other computer, unless the tiny increase in accuracy (and it's still not "perfect") matters to you. How much does it matter to you at the end of the year whether you rode 3000 miles or 3050 miles?
 

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I use an old fashioned Cateye wired cycle computer as well as my phone's free Strava app. I always seem to end the ride with a 0.5 mph lower average speed on Strava than on my Cateye.
 

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My garmin seems fairly accurate, i have a speed sensor paired to it so it can hot fix the gps data. Meaning if i go under a bridge or in some deeply wooded path my trace is not lost.

When i am on the trail it seems to track well with pavement markings, meaning every mile seems about on.
The bolded words correspond with the 1-2% error described in the various posts. Having the wheel sensor for added data to correct the GPS slop makes a difference.

Truth is, any of the devices being discussed are plenty accurate enough for the purposes of anyone here.
 

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I use an old fashioned Cateye wired cycle computer as well as my phone's free Strava app. I always seem to end the ride with a 0.5 mph lower average speed on Strava than on my Cateye.
Same here, I don't need to know the exact miles I ride. A not so accurate measurement is good enough for me.
 

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This is what I do. It's the reason that my GPS Polar is a "watch type". I thought that two computer types would look funny.
 

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I'm kickin' it real old skool with an Avocet 20 (on my vintage 1986 Specialized Allez) and Avocet 30 and 40 on everything else. Unfortunately you can't mount an Avocet 30 on the newer 31.8 sized handlebars. Sigh. It's harder and harder to find working Avocet units and I find it puzzling that some of my units just stop working.

I'm not a fan or wireless units (I don't want to replace two batteries) so I picked up a $13 wired Bell Dashboard 100 at Wally World. Things I like about the Bell unit: battery saving feature and actual time spent riding. Things I don't like about the Bell unit: no stopwatch function and it sits a little too high off my handlebars.
 
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