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Discussion Starter · #1 ·
This is my first foray into the world of GPS and i'm considering these two models from Garmin, the GPSMAP 76CSx and the Edge 305.

Am i right in thinking that the Edge 305 will track where i've been but won't show me a map of where i am while i'm riding? That's the only thing stopping me from getting this model.

I'm hoping the GPSMAP 76CSx allows me to view maps of where i am while riding, but it's not bicycle specific, so has anyone tried this one on their bike and how does it work?

Has anyone been able to use both to compare them?

What are the general pro/cons of each?

Thanks for your time.:)
 

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zoip.
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Hi there -

As far as I understand, the gpsmap 76 series is just a floating, marine-focused version of the gpsmap 60 series. the guts are the same. the edge/60csx debate has been covered pretty widely, do a search and you should find your answer. It comes down to differences in size and number of features, but both are good units.
 

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You are basically correct, the 305 is not a mapping unit, while you can see your "Track" you can't view it as it relates to a basemap or a topo map. It's a good training aid for a bike, but it's not a navigational gps. By that I mean it's not going to route you to places, it may tell you the direction to a entered waypoint, but it won't show your course on a topo or basement.

Basically it's a good training aid for a road or mountain bike course you want to track your improvement on, and that's about it. You get more bike functions, and HR functions in the 305 and it's probably better for amount of information from riding a course.

However, I would never take one out exploring or on say a trip to utah etc. where I might need to rely on it for navigation if something goes fubar. For those things the 76csx is definitely superior hands down. I also won't use a gps unit that only runs 8-10 hours and has to be recharged, that will not take a user replaceable battery. Again this is fine for training rides and such, but unacceptable for backcountry riding or trips where you won't have the ability to recharge it daily.

The problem with the 76csx is it's a large unit to put on your handlebars, and the garmin mount is unreliable with such a large unit. I run a legend on my bars as it has mapping and is a compact unit, however the sirf chip in the 305 and 76csx is vastly superior for reception than the etrex series.

If it were me, if you want something for training to get a lot of ride information get the 305, but for backcountry or navigation use, get the 76csx. If you want both, you will probably end up with 2 units.
 

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I have the 60csx. It is big but nowhere near too big for the handlebars. The garmin mount is actually very good. You will lose the unit in a hard crash, so remember to look for it. i very rarely ride without it. Great for mapping.
 

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I'm having fun with my 60csx.

My $.02 - If you want a bike computer get one for $20 from Performance. If you want a GPS then get the 60Csx.
 

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I did some exploring a little while ago wiht the Edge 305, a topo map, and a compass. If you consult the "experts" many will say using a map and compass is essential and not to rely on any GPS.

What the Edge can be good for is marking a location and being able to find it again. I found a singletrack on day out, and maked the location of it's start point, so next time I went out I was coming from another direction so it was easy to switch to the "map" mode and work toward my dot on the screen. I've done that to find many locations that I marked and wanted to find again later, and it helped to know where those locations where on the topo map as points of reference. If you've already gone a particulare route you can make it a course (which I've done), or a route (which I haven't done) and retrace your steps.

BM

Edit: I would still really dig getting an 60csx, just can't justify it.
 

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I also recommend going for the 60Csx if you want more of a GPS than a bike computer... I use a Polar HR/computer that complements the 60Csx in that regard perfectly ;)
 

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I'll agree with what folks here have been saying. We've got a 76CSx at work....good unit, but it would be a bugger on the bars of a bike. The 60 CSx is smaller and fairly rugged, but it is a navigational GPS, not a cycling GPS like the Edge. The Edge, OTOH, is not for nav. Both will get excellent reception (SiRF chips rule) but it really does depend on how you will use the unit. Decide on what you want/need....nav aid or bike/training tool

Myself, for any time I need a nav capable GPS, I can use one from the office. For my bike, I want more info than I can get from my bike current computer and a small package. The Edge gives me info on grades and vertical profiles, integrated HR and cadence features and the ability to show folks where some of the trails are.

Sure, the 60 can do the GPS part, but for me locally, I'm looking at a lot more expense to get a 60 CSx ($100+ more than an Edge 305), a HRM ($95+) and bike computer with cadence ($40+) for what I want to do with the Edge.
 

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The Edge does one thing very well. If you want to use a GPS for anything more than cycling, it is really horribly limited. The buzzkillers for me were no maps, the non-replaceable battery and non-expandable memory.

The 76/60csx, on the other hand, is massively flexible. It can be worn on a clip for hiking, mounted in-car for highway navigation, used on multi-day back-country trips and so on.

I use the 60 on the bars and it's fine unless you are racing.
 

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pinkheadedbug said:
The Edge does one thing very well. If you want to use a GPS for anything more than cycling, it is really horribly limited. The buzzkillers for me were no maps, the non-replaceable battery and non-expandable memory.

The 76/60csx, on the other hand, is massively flexible. It can be worn on a clip for hiking, mounted in-car for highway navigation, used on multi-day back-country trips and so on.

I use the 60 on the bars and it's fine unless you are racing.
The Edge is a glorified replacement for the cyclecomputer and heart rate monitor combined. The downside of a mapping GPS is that a cyclecomputer is more accurate so, unfortunately if you care about accuracy, you need both.
 

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zoip.
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MikeDee said:
The Edge is a glorified replacement for the cyclecomputer and heart rate monitor combined. The downside of a mapping GPS is that a cyclecomputer is more accurate so, unfortunately if you care about accuracy, you need both.
why is a mapping unit less accurate than the edge, or a cyclecomputer? I'm unclear about this. If both those units use the same SiRF chip and both are recording data at the same rate (1/s max, as I understand) then what difference would there be between them? both should be more accurate than a computer since there's no chance of calibration errors, which are practically the norm with magnetic sensor computers. My feeling (still somewhat unsubstantiated since I haven't done rigorous testing and probably won't bother) is that the small position errors of the gps are far smaller at the end of the day than problems with calibration, starting and stopping, and sensor pickup that plagued my avocet computer (years ago). there's a reason almost all surveying and GIS information is gathered with GPS units these days....
 

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Of course, there is the other issue of getting the sensor mounted....on some big clearance forks and frames, it's dang hard to get a magnet within 5mm of the sensor without having to modify the mount.

I fully understand the limits of something like an Edge....it is made for a certain purpose. If you need the mapping and navigation functions and are looking at an Edge, you'd looking at the wrong equipment...on the flip side, a full on GPS for navigation is going to be heavier, bigger, harder to securely mount on a bike and absolute overkill (both in price and functions) if all you need is a training aid / more powerful bike computer.
 

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ahb said:
why is a mapping unit less accurate than the edge, or a cyclecomputer? I'm unclear about this. If both those units use the same SiRF chip and both are recording data at the same rate (1/s max, as I understand) then what difference would there be between them? both should be more accurate than a computer since there's no chance of calibration errors, which are practically the norm with magnetic sensor computers. My feeling (still somewhat unsubstantiated since I haven't done rigorous testing and probably won't bother) is that the small position errors of the gps are far smaller at the end of the day than problems with calibration, starting and stopping, and sensor pickup that plagued my avocet computer (years ago). there's a reason almost all surveying and GIS information is gathered with GPS units these days....
Position errors add up. GPS signal can be degraded or lost. Look at a track in Google Earth or Mapsource and you can see some of the errors. The Edge 305 uses a wheel sensor in addition to the GPS for more accuracy.

It doesn't take much to accurately calibrate a cyclecomputer (just a roll-out of the wheel on the garage floor).
 

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I don't think I totally buy that argument. Your cycle computer (that works off of tire circumference) can be off if just your air pressure isn't the same as what you calibrated it to. Or what if you put on a 2.25 from a 2.1 you had before? You'd have to recalibrate it every time. And even a small inaccuracy in true tire circumference adds up over longer distances, being cumulative, where GPS works off of absolute position. Either way, I'd have think the difference is pretty much trivial. Neither will be off by miles. When I first got a Forerunner I rode with it in conjuction with my cateye HB100 and the distances were always identical, and considering the Edge is supposed to be more accuate it's probably not even an argument worth, uh, arguing over.

Even so, if you want to get all fancy, doesn't the full boogie woogie edge also have a wheel and cadence sensor too, giving redundant speed and distance measurements? If I recall right it has an auto calibrate wheel diameter function, or a manual input of your wheed circumference.

BM
 

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pinkheadedbug said:
The buzzkillers for me were no maps, the non-replaceable battery...
It's worth mentioning that there are homebrew extended battery kits posted on the internet for the Edge using a 9V battery and junk from Radio Shack to make an external 5V power source. I've looked it up in the past, but if you are realling into extended rides (longer than the 13hr battery life, if it really lasts 13hrs) it'd be worth looking in to. As much as I've been riding this winter, I only have to charge mine once or so a month :(.

BM
 

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Discussion Starter · #16 ·
Thanks everyone for the info. I'm looking at he 60CSx more than the 76CSx now. Definitely not going to bother with the Edge 305 as i've already got a cycle computer.

As for the GPS inaccuracy comment, how far out is it compared to a regular cycle computr and what functions are affected?
 

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zoip.
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As for the GPS inaccuracy comment, how far out is it compared to a regular cycle computr and what functions are affected?
if the GPS has good signal, it should agree very well with a properly calibrated computer. any differences are far too small to be concerned with. we're talking fractions of a percent here....although all this talk is making me curious to dig out the ol' avocet 45 and strap it onto the road bike for some comparison testing.

best of luck. I recently got a 60csx and am having a ball with it. great toy......
 

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bmadau said:
I don't think I totally buy that argument. Your cycle computer (that works off of tire circumference) can be off if just your air pressure isn't the same as what you calibrated it to. Or what if you put on a 2.25 from a 2.1 you had before? You'd have to recalibrate it every time. And even a small inaccuracy in true tire circumference adds up over longer distances, being cumulative, where GPS works off of absolute position. Either way, I'd have think the difference is pretty much trivial. Neither will be off by miles. When I first got a Forerunner I rode with it in conjuction with my cateye HB100 and the distances were always identical, and considering the Edge is supposed to be more accuate it's probably not even an argument worth, uh, arguing over.
BM
Yes, I think you're right. My overall miles for the GPS is just .1 mi. less than with the cycling computer, and my wheel size is probably off because I switched tires. But what's bothering me is that the moving average speed of the GPS is showing .3 mph lower than the cyclocomputer. I suspect the GPS is wrong.
 

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zoip.
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I've noticed that the averages drop precipitously if you're stopped, but the GPS unit doesn't "think" you've quite stopped. say you've ridden exactly 12.00 miles in exactly 60.0 minutes. 12 mi/hr, right? well a drop to 11.7 miles per hour would take only 1 minute and 30 seconds of extra time - 12.00 miles covered in 61.5 minutes is 11.7 mph. three or four stops in the course of an hour where you've come to a stop but it takes the gps unit a few seconds to figure it out, maybe another 30 seconds while you click through buttons to observe the average, and there's a plausible explanation for the drop in average speed - my guess is that the GPS unit does its averages simply by total miles covered divided by total moving time. it's the very slow-speed movement that artificially drops the average. Doesn't the edge have basically a low-pass filter that doesn't track the data below a certain mph? that would seem to remedy this problem, if you can even call it a problem. 0.3 mph doesn't seem to be anything to be concerned about, in the scheme of things....
 

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ahb said:
I've noticed that the averages drop precipitously if you're stopped, but the GPS unit doesn't "think" you've quite stopped. say you've ridden exactly 12.00 miles in exactly 60.0 minutes. 12 mi/hr, right? well a drop to 11.7 miles per hour would take only 1 minute and 30 seconds of extra time - 12.00 miles covered in 61.5 minutes is 11.7 mph. three or four stops in the course of an hour where you've come to a stop but it takes the gps unit a few seconds to figure it out, maybe another 30 seconds while you click through buttons to observe the average, and there's a plausible explanation for the drop in average speed - my guess is that the GPS unit does its averages simply by total miles covered divided by total moving time. it's the very slow-speed movement that artificially drops the average. Doesn't the edge have basically a low-pass filter that doesn't track the data below a certain mph? that would seem to remedy this problem, if you can even call it a problem. 0.3 mph doesn't seem to be anything to be concerned about, in the scheme of things....
I wonder if you set the unit to track by miles instead of time on the Track Page Options, that might act as a filter. Mine is set to Auto which I don't know what that means and the manual is unclear. Or maybe the trip computer doesn't use the track log in computing its data.
 
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