G.P.S Does it have to be cycling specific

Matty1235

Hi,

I'm looking at getting a Garmin GPS computer, my question is does it have to be cycling specefic, I'd like a computer I could where as a watch eg the forerunner, i'm not interested in heart rate or cadence, just speed and altitude.

Thanks

STEFANOS4784

From what i've heard on here gps aint 100% accurate for either of your requirements, i stand to be corrected(again) though

airborne_warrior

GPS are very accurate down to usually around 6 metres. It tells you on the screen the accuracy reading. This depends on how many satellites are in the vicinity above you. In the UK usually quite a lot! All GPS i know of give speed and altitude.

STEFANOS4784

And i stand here corrected :oops:

airborne_warrior

The US defence agency used to have an error reading signal purposely transmitting from GPS satellites (they own them all!) This was to stop terrorist organisations from using GPS guided missiles accurately. This device was turned off during the Iraq war and stayed turned off. They can turn it on again when the need dictates.

STEFANOS4784

Airborne Warrior wrote:

The US defence agency used to have an error reading signal purposely transmitting from GPS satellites (they own them all!) This was to stop terrorist organisations from using GPS guided missiles accurately. This device was turned off during the Iraq war and stayed turned off. They can turn it on again when the need dictates.

:shock:
However i do remember reading threads about rediculous times/altitudes/top speeds frrom Garmin type contraptions :?

airborne_warrior

I should think that is a malfunctioning GPS rather than a malfunctioning satellite though!

trickeyja

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u01akrg

I've had a Garmin Edge 205 (no cadence or heartrate) for 2 years and think its brilliant. I've regularly compared stats with other's computers on club rides and they've always been pretty close. I've even compared to the car speedo and odometer, again always agree closely. The only time I appeared to hit hyperspeed was when I had a light mounted next to the GPS on my handlebars - getting a couple of extra inches of a gap between them sorted that out.

As the Edge series is designed as a bike computer I reckon it is better than the Forerunner or other models for cycling specifically. But then I rarely run or navigate with the GPS. I guess it all depends on what you want from the device - the other models are likely more flexible.

trickeyja

I have a Magellan Explorist XL which has served me very well over the past couple of years. I don't use it much since I got a road bike since it's too bulky and I quite enjoy finding my way using traditional maps.

Any GPS with speed, distance and route logging facilities should work well with a bike but the things to look for are a computer connection, light weight and an optional bike mount. Naturally GPSs that are optimised for cycling such as Garmin Edge series are going to be more suited to the cyclist. These ones are likely to have more features such as heart rate and cadence monitors and virtual training partners (see https://buy.garmin.com/shop/shop.do?pID=10885#specsTab). However that doesn't mean to say standard GPSs won't be good if not a lot cheaper.

When I was using my Magellan I enjoyed reviewing rides on the computer afterwards, and being confident to explore more obscure roads using routes I had prepared beforehand. Inaccurate data was not really an issue, other than unreliable max speed. However when there was lost signal the GPS sometimes cut out causing the distance calculated from the speed and time on the unit to be inaccurate. The track log is normally spot on though because it corresponds with a map.

trickeyja

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trickeyja

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trickeyja

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trickeyja

-PLEASE DELETE-
BikeRadar was being slow submitting and has made copious multiple posts!

craker

I've got the forerunner 405 which is more of a running watch than a cycling one, accuracy is brilliant (better than my old etrex), do'nt think about using it for navigation though it's not really built like that.

On me handlebars last weekend it was accurate with my cateye computer to <0.5 mile over 32 miles (and who knows what the right number is?) although I have loaded up route maps afterwards and seen it take straightlines between location points that were on a bend, (I think it takes a reading every ten seconds or so)

Not very good for speeds though, it is slow to respond to changes of speed due to its sampling frequency, don't expect your max speed to be accurate and you're current will be fine if you keep it steady for 10s of seconds

I think there is a cadence sensor and certainly a heart rate strap.

Oh, I'm not sure where it gets it's altitude numbers from. GPS is 2D isn't it? So elevation either comes from an internal barometer of from mapping.

If you're got a few bikes it makes a great all machine speedo, maybe you'd want a computer on a road bike.

GavH

Get a Foretrex 101. It can be worn as a watch as it comes on a velcro strap. It'll give you altitude, distance and speed. I have used it alongside my Polar CS600 and it give almost exact, matching readings against the Polar. I used it to plot the grid refs of junctions I was unfamiliar with on longer rides so I knew when and where to turn. They can be had on ebay brand new for about £70 which was where I got mine from just over 2 yrs ago, never let me down and I've used it cycling, running and principally for hill walking and mountaineering.

FatLarry

I've used a Garmin Forerunner 305 for 18 months. I initially bought it to help me train for the marathon, then I started using it on my bike.

I have a bike mount and the cadence senser.

On the positive side...

It's a motivational tool - I use it for my commute (21 miles) and was able to track my continual improvement - going faster, keeping a lower heart rate, etc. And, being the competitive sort, I use the "virtual partner" functionality to race against myself on yesterdays' commute...

I use mapmyride to plan 70mile+ routes on unknown minor roads and download them as "courses" to the device. I've never got lost. With the tools you have on the web, you don't need street maps on the device. Anyone who tells you you can't use this for navigation just hasn't worked it out yet.

I've also used it when I've been away from home and unable to plot a route - I can just go where I fancy for 15 miles then use the device to find my way back to wherever I started.

I'm a bit of a statto, so it provides added pleasure and entertainment. I can compare my rides and work out where I lost time, etc. And I've a complete record of all my running and riding over the last 18 months. (The software stores them under the different training activity)

I still get the full 8 hours + battery life per charge. I was expecting that to dwindle.


Negatives

The bike mount isn't an attractive feature. It's a ruddy big lump.

It took me 9 months before I worked out how to make good use of the navigation features. It ain't easy to work out. And the manual doesn't really help.

Altitude is a bit iffy. On a six mile loop I run, it will tell me I've ascended 50m more than I've descended. Even though I'm back exactly where I started.

It can take a while to fix on a signal. But, once it's fixed, it seems stable. I've only lost signal once in 18months. And I run and ride in some pretty thick woods.

Hope that helps...

FSR_XC

+1 for the Forerunner 305.

Been using mine for over a year. It does everything the Edge 305 does without the bulk.

Only thing that FatLarry missed is that it is bulky worn on the wrist. The 405 could be a better choice if you want to wear it as a watch.

FatLarry

You're right, it is big on the wrist. The 405 is certainly a sexier, more modern and subtle looking wrist ornament.

But whilst it felt a little awkward to start with, after a few runs I got used to the size of the 305.

I missed another positive. The 305 is red. And it's been scientifically proven that red is actually the fastest colour on the planet.

fnegroni

mr_si wrote:

On me handlebars last weekend it was accurate with my cateye computer to <0.5 mile over 32 miles (and who knows what the right number is?) although I have loaded up route maps afterwards and seen it take straightlines between location points that were on a bend, (I think it takes a reading every ten seconds or so)

In the case of the Edge x05 series (205 here), you can configure the rate at which it saves points. The sampling rate is the same, and pretty high freqency too, I use it off road and on road and it is pretty accurate. But to save on memory usage, the default setting is to be 'smart' about saving the waypoints, so it only saves waypoints if it thinks they are relevant. If you go in a straight line or just about, and it does not make much difference in terms of average speed/distance, it will only save two points rather than 3 say, and that makes a bend a little bit like a straight line.
Try changing the setting to maximum memory usage, and it will be a lot more accurate when uploading the route.
The sampling rate (that is, the frequency it reads the signal from the satellite) is the same though.

Matty1235

Thanks for all the replies, I nearly went for the Foretrex but the cheapest I could find it with Postage and in stock was £86, so for the extra £20 I went for the Forerunner 205, the only difference to the 305 seems to be heart rate, which for me is not important.

Cheers