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calling all garminologists

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calling all garminologists

Old 09-28-08, 06:42 PM
  #1  
bob the nailer
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calling all garminologists

I am considering updating from what i currently use, a campy ergobrain, to a garmin. I would like it to do heart rate, speed, cadence, altitude, elapsed time and distance, have autostop. After visiting the garmin site, looks to me like i need the 705. any opinions?
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Old 09-28-08, 06:49 PM
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I've had one(705) for 2 months and am very impressed with it so far. Do it.
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Old 09-28-08, 06:51 PM
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The 305 gives you all that, but without the color screen and enhanced maps, for a lot less coin.
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Old 09-28-08, 07:08 PM
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You need the 305 or the 705 for the functions you are looking for.

705 adds maps, color screens, and a few hundred Dollars.
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Old 09-28-08, 07:11 PM
  #5  
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I love my 305, but honestly with either unit you will most likely have to deal with Garmin's glitchy hardware.

The unit is awesome and the benefits far outweigh the minor inconviences every now and then.
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Old 09-28-08, 08:22 PM
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Why do these things use barometric pressure instead of gps for altitude? Couldn't they use both and be close to flawless?

By the way, are there any other computers (not made by Garmin) that do everything the 305 does?
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Old 09-28-08, 09:13 PM
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305 w/cadence/HR kit will get you all that and more.

If you want the extra bling and maps get the 705.
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Old 09-28-08, 10:18 PM
  #8  
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Originally Posted by JaRow View Post
Why do these things use barometric pressure instead of gps for altitude? Couldn't they use both and be close to flawless?
Well, I can tell you that the airplanes I fly use barometric pressure for altitude and it seems to get the job done fairly well. We trust our altimeters enough to fly down to 200 feet above the ground in the clouds, unable to see the ground. The GPS I have in my airplane will tell you altitude as well but mine is not approved to be relied upon for that function. I agree that a mixture of both would be really accurate, but barometric pressure is tried and true.

Oh, and I have the 705 and really enjoy it. If you ever are going to consider a power meter, the 705 is the way to go too. I've never used a 305 so I don't know how good it is. I got my 705 barely used with HR strap and cadence sensor for $325.
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Old 09-28-08, 10:27 PM
  #9  
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My 705 does all that stuff. Add some maps. I love mine. Was just looking at my cross race from today.... ugh 45 min of pain,
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Old 09-28-08, 10:59 PM
  #10  
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Originally Posted by Copperhed51 View Post
Well, I can tell you that the airplanes I fly use barometric pressure for altitude and it seems to get the job done fairly well. We trust our altimeters enough to fly down to 200 feet above the ground in the clouds, unable to see the ground. The GPS I have in my airplane will tell you altitude as well but mine is not approved to be relied upon for that function. I agree that a mixture of both would be really accurate, but barometric pressure is tried and true.
The difference with altimeters is that you have ATIS to tell you what pressure setting to put your altimeter on. I doubt these computers do that which means that a temperature change would result in an "altitude" change.
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Old 09-29-08, 12:09 AM
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Originally Posted by JaRow View Post
The difference with altimeters is that you have ATIS to tell you what pressure setting to put your altimeter on. I doubt these computers do that which means that a temperature change would result in an "altitude" change.
True, I imagine the garmin is probably not completely accurate on the actual altitude but as far as altitude change, it should be. If my altimeter is not set correctly and I climb 100 feet, it will still show that I climbed 100 feet but will indicate an incorrect altitude above sea level. That's no good when flying airplanes but riding a bike, I'm mostly concerned with elevation change, not the actual altitude. Yeah, temp and pressure change throughout the day and that would effect it but I still think it's plenty accurate.
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Old 09-29-08, 02:13 AM
  #12  
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if i'm not mistaken, the 305 uses both barometric and GPS altimeter. on start up, it calibrates via GPS altimeter. and then every so often (not sure how often) it re-calibrates with GPS altimeter.
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Old 09-29-08, 06:13 AM
  #13  
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Originally Posted by Copperhed51 View Post
Well, I can tell you that the airplanes I fly use barometric pressure for altitude and it seems to get the job done fairly well. We trust our altimeters enough to fly down to 200 feet above the ground in the clouds, unable to see the ground.
You also don't have tractor trailers passing you at 70 knots just 3' off your port side either.

That said, the garmin does (supposedly) use a combination of GPS and barometric pressure to composite it's elevation figures.

The 305 does what the OP asked for. The 705 does it, and more. And the real advantage of the 705 over the 305 in his case would be the longer battery life in the 705. The 305 never had enough battery for long days. The 705 does. Or so says my buddy who replaced his 305 w/ a 705. My 705 is on order, but won't be here until friday.
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Old 09-29-08, 06:14 AM
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Originally Posted by Copperhed51 View Post
True, I imagine the garmin is probably not completely accurate on the actual altitude but as far as altitude change, it should be.
Ironically, I think the opposite is true. The Garmin works well w/ actual altitude, but the altitude change gets whacked... by the pressure changes caused by traffic is my guess.
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Old 09-29-08, 06:25 AM
  #15  
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I have the 705 and I've all but given up on the altitude feature except for displaying the elevation profile of a ride. It does pretty good on that. I've had to peddle hard up some hills that it registered as -3% downgrade, and I've coasted down a 12% upgrade as well. Averaged over time, it works fine, but the device definately has issues with altitude.

If I had to buy it over again, I'd probably go with the 305... the maps are cool and all, but really not all that cool. I can wait until I get home to plot the route on a map.
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Old 09-29-08, 08:08 AM
  #16  
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Originally Posted by JaRow View Post
Why do these things use barometric pressure instead of gps for altitude? Couldn't they use both and be close to flawless?

By the way, are there any other computers (not made by Garmin) that do everything the 305 does?
There are a number of Polars that allow you to connect to a computer to graph your heart rate, speed, cadence, distance and elevation profile all on the same graph, or separate them out if your want to. The altimeter in the Polars is barometric only, but is much more consistent and has way less variance for the results for the cumulative ascents for known rides than the Garmins do. You can look at the cumulative ascents for big rides posted at motionbased.com by Garmin users and you will notice the reported cumulative ascents varying practically as much as 40%. For example, check the cumulative ascents posted for the 206 mile Lotoja race at Motionbased.com. Also, there are no battery issues for long days in the saddle with a Polar. However, you can't load your ride in to Google maps like you can with a Garmin.

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Old 09-29-08, 08:13 AM
  #17  
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GPS is +/- 100 feet for altitude by combining barometric readings, it gets much better at registering change. The longer the device is on at a single altitude, the more accurate the actual altitude that gets calibrated will be. Also, it depends on how many satellites you are tracking. It takes 3 to get a 3D reading.
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Old 09-29-08, 08:26 AM
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Hello bob the nailer,

I had a 305 for 2-1/2 years and I just replaced it with a 705 a few weeks ago. Either of these units provide the information that you listed. The main difference is that the 705 has a bigger, easier-to-read display, full navigation capability, and is bigger and weighs more.

If you want full GPS navigation with turn-by-turn directions you will have to spend about $100 for the map data on a micro SD card. I travel somewhat regularly and decided to get the card so that I could use the GPS functions while on travel. I used it last week and it worked very well.

Regarding altitude, as others have mentioned, the 305 and 705 use a combination of barometric and GPS information to read altitude and calculate elevation gain/loss. The problem comes when you start a ride with a significantly different starting elevation than the last or when the local barometric pressure changes significantly. It took the 305 five or so minutes to recalibrate its altitude reading in the above conditions. So far the 705 seems to do this faster -- more like 2-3 minutes. Yesterday I was riding in the local mountains and the elevation reading on my 705 were pretty close to the roadside elevation markers. The ride started at about 500 ft and got as high as about 4,500 ft.

BTW, if you get either unit, try SportTracks to download and analyze your ride data. IMHO it's much better than Garmin Training Center or Garmin MotionBased or Garmin Connect.

Hope this helps.
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Old 09-29-08, 08:31 AM
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Originally Posted by nycphotography View Post
You also don't have tractor trailers passing you at 70 knots just 3' off your port side either
Let me know the next time you do "hood" work on your bike using the Garmin. The addition of a big pope style hood would make for quite an interesting ride. I've still got a hood from my days as a flight instructor, if you want to borrow it for a bike ride. (Note: A hood is a big white plastic thing I'd put on a student to block outside vision, simulating flying in the clouds. Pilot stuff)

My altitude / grade function work great on my 705. I just got mine about 2 months ago. Satellite reception is excellent too. No drops in the woods. I remember some mention of software problems with the early 705's. Might check in with Garmin support for any available software upgrades.
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Old 09-29-08, 08:41 AM
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Originally Posted by nycphotography View Post
You also don't have tractor trailers passing you at 70 knots just 3' off your port side either.

That said, the garmin does (supposedly) use a combination of GPS and barometric pressure to composite it's elevation figures.

The 305 does what the OP asked for. The 705 does it, and more. And the real advantage of the 705 over the 305 in his case would be the longer battery life in the 705.
The 305 never had enough battery for long days. The 705 does. Or so says my buddy who replaced his 305 w/ a 705. My 705 is on order, but won't be here until friday.
I have routinely used my 305 for 10 hours at a time. I don't remember it ever really running out of battery on those days. If this doesn't qualify as a "long day" by your definition then you are right...the 305 doesn't have the battery life for you.
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Old 09-29-08, 08:51 AM
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For those having problems with the battery life of your 305, are you recording one point per second, or are you using the smart record function?

It is my understanding that this can affect batter life.
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Old 09-29-08, 09:10 AM
  #22  
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the 305 is really great- and i imagine that the 705 works the same just better. the only (IMHO) problem with the 705 is that it's bigger and heavier. the maps function must be amazing if you ride in unfamiliar territory. i was riding in vermont last week and i wish i had the 705 for the color maps.

the garmin software is mediocre, and ever worse if you have a mac. for a pc, get sporttracks (it's free) and for a mac, ascent is very good for downloading your info.

btw- the best deal i found on the internet for the garmin was at geoman. great price and service.
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Old 09-29-08, 10:02 AM
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Originally Posted by Psimet2001 View Post
I have routinely used my 305 for 10 hours at a time. I don't remember it ever really running out of battery on those days. If this doesn't qualify as a "long day" by your definition then you are right...the 305 doesn't have the battery life for you.
battery life can definitely vary. My 305 lasted for 8 hours on a recent ride but was dangerously close to zero bars by the end.
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Old 09-29-08, 11:05 AM
  #24  
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Originally Posted by Cleave View Post
BTW, if you get either unit, try SportTracks to download and analyze your ride data. IMHO it's much better than Garmin Training Center or Garmin MotionBased or Garmin Connect.

Hope this helps.
Or Ascent if you're on a mac.
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Old 09-29-08, 11:50 PM
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And if you do get it - make sure you upgrade to the latest level of the firmware! A lot of issues have already been sorted out.
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