Cycling UK Forum

andymiller wrote:[so unless you are required by the regulations to use a barometric altimeter, the eTrex 230 will do the job just as well.

GPS altitude data is often subject to quite a lot of jitter, with the result that "total climbing" numbers can be inflated by a lot - like up to 30%.
The calibration drift that you get with a barometric altimeter doesn't have nearly such a big effect.
It only really matters if you are doing DIY audax rides - calendar events and regular permanents should have an agreed figure, or at least a history of previous claims.

The trouble with non-Garmins is that without the same size of user community, things like OSM appearance, update frequency or the availability of data for non-standard areas (eg for a cycling holiday in Kerala) is at the whim of the manufacturer.
I'm sticking with my eTrex HCx until it expires. Hopefully all of the bugs in the later 20/30/dakota etx software will be fixed by then.

I was in a similar position last year of trying to decide on a GPS, but even within the Garmin range there are a great many variations on functions and features. Since I couldn't decide, I bought a cheap, £40, eTrex Legend C off ebay with the intention of using it for a while and deciding which features were important to me. It doesn't have Garmin maps on it and there's no SD card slot. So I use openstreetmap and upload that to the unit, plan my route(s) in Mapsource and after perhaps 20 long day rides, I think it's great. Yes there are some things missing from it, but for £40 it's been a great purchase and if I ever make a decision to buy a new one, I can probably still sell it for the same as I paid for it.

andrew_s wrote:

andymiller wrote:[so unless you are required by the regulations to use a barometric altimeter, the eTrex 230 will do the job just as well.

GPS altitude data is often subject to quite a lot of jitter, with the result that "total climbing" numbers can be inflated by a lot - like up to 30%.
The calibration drift that you get with a barometric altimeter doesn't have nearly such a big effect.
It only really matters if you are doing DIY audax rides - calendar events and regular permanents should have an agreed figure, or at least a history of previous claims.

The trouble with non-Garmins is that without the same size of user community, things like OSM appearance, update frequency or the availability of data for non-standard areas (eg for a cycling holiday in Kerala) is at the whim of the manufacturer.
I'm sticking with my eTrex HCx until it expires. Hopefully all of the bugs in the later 20/30/dakota etx software will be fixed by then.

I've seen my eTrex 20 give occasional anomalous results - every so often the gps system seems to have an off moment and accuracy goes from the normal 2 or 3 metres to maybe 20 or so. I use my gps almost every day, all day, five months of the year and this happens maybe once or twice a month. I ride with a topographic map and the results of the gps are consistently within the stated accuracy - usually 2-3 metres. The data on the elevation display doesn't fluctuate. Occasionally if there's a weak signal, you can get a delay before the displayed elevation updates; I assume this also affects the recorded elevation - but this isn't going to impact on the total amount of climbing.

One day, I must do a climb with a known amount of altitude gain and compare that with the results from the eTrex. I wonder if anyone has ever done a head to head comparison of an eTrex 20 and an eTrex 30 on the same course at the same time.

I don't have any real experience with a barometric altimeters but I suspect you'd have to calibrate it very very carefully to get similar accuracy with a barometric altimeter (ie normally within 1 percent - although obviously this depends on the altitude where you are riding - if you are riding at low altitudes then 2 or 3 metres is going to be a greater error). I have seen the readings from a barometric altimeter (admittedly one built into a not very expensive cycle computer) quite dramatically affected as a low-pressure weather front swept in.

You do get gps noise if say you use a sight like gpsies.com and use the add/replace elevation - this does seem to introduce a lot of fluctuations if you are riding a road through steeply sloping terrain - the gps unit isn't (so far as I can tell) subject to the same problem.

I have used both the HCx and the eTrex 20 a lot. I've not experience any significant bugs with the eTrex 20 - although I've certainly had the occasional crash, as I did with the HCx. The eTrex is at least as reliable as the HCx - probably more so. Garmin to their credit have made a number of improvements to the firmware over the last couple of years (as well as bug fixes). The eTrex 10 and 30 ae significant advances over their predecessors. If you tried one I think you might appreciate the advantages.

I should of course have said 'eTrex 20 will do the job' in my original post not 230.

lads i have a chance of buying the garmin 705 for 150 euro might even get it a bit better any thoughts on this thanks.

I had a Garmin eTrex Legend. It was pony.
I had a Garmin Edge 605. It was worse.
I have another manufacturer's product now. It is Ace.

Ayesha wrote:I had a Garmin eTrex Legend. It was pony.
I had a Garmin Edge 605. It was worse.
I have another manufacturer's product now. It is Ace.

Which one is that?

Ayesha wrote:I had a Garmin eTrex Legend. It was pony.
I had a Garmin Edge 605. It was worse.
I have another manufacturer's product now. It is Ace.

so would you like to share please.

jags wrote:

Ayesha wrote:I had a Garmin eTrex Legend. It was pony.
I had a Garmin Edge 605. It was worse.
I have another manufacturer's product now. It is Ace.

so would you like to share please.

Do a quick search on Ayesha's posts you'll soon find out.

andymiller wrote:

jags wrote:

Ayesha wrote:I had a Garmin eTrex Legend. It was pony.
I had a Garmin Edge 605. It was worse.
I have another manufacturer's product now. It is Ace.

so would you like to share please.

Do a quick search on Ayesha's posts you'll soon find out.

So Andy, you don't know either

Well I've been more than happy with my Edge 605* that I've been using for the last 5½ years. It will still happily chug away for at least 14 hours straight without running out of juice.

The only thing I quickly learned not to do was use it to try to navigate by itself, unless I really needed to. There wasn't much wrong with the navigation per se but if you missed a turn it was glacially slow at recalculating, by which time - if you carried on riding - you had probably missed its recalculated turn so it would start all over again... Definitely best to stop while it thinks.

Rick.

PS Edited to add that there's a clue from Ayesha in one of his earlier posts in this discussion.

(*the 605, AFAIK, is identical to the 705 apart from lacking a barometric altimeter and wireless connectivity to additional kit)

ok i'm gonna go for the etrek 20

thanks everyone i'll trouble you lot no more.

The good folks on YACF ( which is the AUK unofficial fanzine site ) now accept that ( because some of them have seen it work ) my navigation tool is a dependable and user friendly device with adequate functionality and capability to be used on any Audax ride.

People on the CTC web forum, CycleChat and others are still 'blinkered' when the subject of bike navigation devices is raised.
Some reaction is downright aggressive, sarcastic and infantile.

The GPS guru, mssr Frankie, has never attempted to ridicule my choice of equipment publicly. He has respect for other people's decisions.

beetroot wrote:So Andy, you don't know either

Ayesha has never been afraid to bang the drum for this manufacturer. And if you want a gps that's designed for a motorbike, has a battery life of a whopping 6 hours, doesn't do topographic maps (or any third-party maps?), doesn't have an SD card slot, and costs £250, then it's well worth considering. Maybe it does autorouting well - if that's important to you. Bike-specific, but sadly the wrong sort of bike.

After three years use, I have not yet needed to contact TomTom Europe with any technical problems.
Building an Itinerary on Tyre toTravel routing package is as simple as using Googlemaps to create a DIY route for the Audax DIY Organiser.
I receive a map update approx. every three months ( 4 per year ). A notice appears when I connect the device to my PC and TomTom Home boots up automatically, therefore, third party mapping isn’t needed.
A USB battery pack extends life indefinitely.

Topographical mapping isn’t important to me. I can look at an Audax route on BikeHike to see how flat it is.
I don’t require a SD card slot. The completed brevet card is my proof of completion. That has the length of the event and my finishing time written on it.

Navigation is however, the most important criteria on my list of priorities.
It is all well and good owning a device which tells you where you’ve been, how fast you went and how long it took you, but IF the device has problems working out a suitable route to take, all the recorded data in the world is worth nothing.
When I had a Garmin, I could review the wrong turns I made when following Garmin’s inadequate routing.

Horses for courses, hey.

I made my choice and live happily with it with no continual scouring YACF for answers to operational issues.

705 for me.
No regrets, it does everything I want it to do, and it does it well too.
Worth every penny.

Navigation?
I never ever bother with it unless I want a laugh. I didn't buy it to let it navigate for me, I can do that very well myself thank you very much.

If I do want a route to follow, I create one on BikeHikUK and save it as a TCX and load it into the Courses folder and follow a pink line on the map. It'll tell me how far I have to go and how long it will take me to get back to the pub for a beer.