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smarauder68

Device that tells you the gradient

Everytime I take on a new hill/mountain here in Salt Lake, I'm curious to know the gradient I'm climbing.  I stopped at a bike shop during my lunch and Garmin sells a gps product that includes gradient.  It runs for 349.00 and I don't think I need the GPS, I just want a device that tells me the gradient instataneously.

Do any products like this exist and can they be found for a decent price or is 350.00 the going rate?
Fontfroide

http://www.skymounti.com/html/gb.html

Tell me if works well. I was thinking about getting one for exactly the same reasons..
SlowRower

Re: Device that tells you the gradient

smarauder68 wrote:
Everytime I take on a new hill/mountain here in Salt Lake, I'm curious to know the gradient I'm climbing.  I stopped at a bike shop during my lunch and Garmin sells a gps product that includes gradient.  It runs for 349.00 and I don't think I need the GPS, I just want a device that tells me the gradient instataneously.

Do any products like this exist and can they be found for a decent price or is 350.00 the going rate?


In my experience, Garmins are cr*p at instantaneous measures, particular when things are changing.

The current speed on my Garmin can be out by as much as 5kmh relative to my Cateye when I'm speeding up or slowing down. The instantaneous gradient reading is a work of fiction; much less accurate than estimating from what the slope looks like and how it feels.

My Garmin is the 405CX, which is 2 year old technology and aimed at running. Newer, bike specific Garmins might be better.
CapeRoadie

Fontfroide wrote:
http://www.skymounti.com/html/gb.html

Tell me if works well. I was thinking about getting one for exactly the same reasons..


Brilliant!
Biosphere

Re: Device that tells you the gradient

smarauder68 wrote:
Everytime I take on a new hill/mountain here in Salt Lake, I'm curious to know the gradient I'm climbing.  I stopped at a bike shop during my lunch and Garmin sells a gps product that includes gradient.  It runs for 349.00 and I don't think I need the GPS, I just want a device that tells me the gradient instataneously.

Do any products like this exist and can they be found for a decent price or is 350.00 the going rate?


GPS is not very good for altitude. The Garmin's include a barometric unit for the altitude measurements. You can get cheaper bike computers with a barometric unit but no GPS. For example

http://ciclosport.com/en/produkt/116/cm-434-blackline

and since you speak German (if I recall), about €120 is the anticipated price including Steigungs-/Gefälleanzeige in % but I doubt it would be any more instantaneous than a Garmin

http://www.futurumshop.de/product...radcomputer-mit-h-henmesser.phtml

The old Ciclosports had onboard memory, so the altitude was downloadable when you get home. I presume that is continued with newer models.

If you want instantaneous, then FFs analogue spirit level is the way to go. I saw one on bike in LBS last week and was told it works well.

If you want to play with open data from Google and Open Street, then the attached HTML will be good. I've centred it on Salt Lake City for you and to give an example just clicked once by the University, and once up what was obviously the climb up Route 65. Google's auto routing does the rest and gives a profile and analysis. I increase the resolution to 500m to smooth the data - unless you know someone who can supply you with military grade data Wink

Works anywhere in the world that Google has data for. The profile is interactive as you waggle your mouse over it. Those who would like a personalised copy but can't figure out how to change the default launch location from the HTML file should post/PM a request with their preferred default, or if they prefer I'll write more detailed instructions on how to change, if they would rather their privacy.

PS: It's another gift courtesy of my mapping oriented friend so I don't take any credit.


Example Screenshot


Click to download file
berck

Garmin's with the barometric sensors are very accurate with their GPS readings. Altitude is always the last thing to warm up correctly, but I find mine within about 20ft of truth.

I usually use the GPS data from the ride to compute the hill climb gradients. The gradient value on the GPS can be about +/- 2 degs off. From what I read about the inclinometer that FF suggested, its not much better.

Somewhere, I came across a guy who made a homemade inclinometer. I can't find it now, but it didn't seem too difficult to do.
smarauder68

berck wrote:
Garmin's with the barometric sensors are very accurate with their GPS readings. Altitude is always the last thing to warm up correctly, but I find mine within about 20ft of truth.

I usually use the GPS data from the ride to compute the hill climb gradients. The gradient value on the GPS can be about +/- 2 degs off. From what I read about the inclinometer that FF suggested, its not much better.

Somewhere, I came across a guy who made a homemade inclinometer. I can't find it now, but it didn't seem too difficult to do.


Can you reccommend a good GPS model? The shop I went to had 2 models. One went for 349.00 and the other about 149.00. I can't remember the names of the models.

I really don't need all the bells and whistles. I just want to know the gradients.
Biosphere

berck wrote:
Garmin's with the barometric sensors are very accurate with their GPS readings.


Yeah, they supposedly do a nice bit of cross checking between the two measurements to give something pretty reliable. When you say you use the GPS data at home, is the output data split between the GPS measurement and the barometric measurement, or are you talking about the Garmin device output in general?
berck

Biosphere wrote:

Yeah, they supposedly do a nice bit of cross checking between the two measurements to give something pretty reliable. When you say you use the GPS data at home, is the output data split between the GPS measurement and the barometric measurement, or are you talking about the Garmin device output in general?


I download the Garmin data into another program (Topofusion). I suspect that the altitude data has already been factored in with the barometric measurements. I'll I get is time, latitude, longitude and altitude.

Its fairly stable and much better than my Garmin GPS60cx without the barometric sensor. I use Topofusion to view the finer detail of climbs I do to determine average grades.

I have found that the beginning of the ride is when it will have the most difficultly getting the altitude correct. Once the barometric sensor and satellites get in sync, its pretty reliable for the rest of the ride. I usually help it along by letting it sit and settle for about five to ten minutes before the ride, but its no guarantee.

My 60cx gets to the correct altitude faster, but its way more unstable. Altitude goes particularly squirrely when under trees and in canyons. My original Trex made better altitude measurements, but lost signal more under the trees than the newer units.
berck

smarauder68 wrote:

Can you reccommend a good GPS model? The shop I went to had 2 models. One went for 349.00 and the other about 149.00. I can't remember the names of the models.

I really don't need all the bells and whistles. I just want to know the gradients.


Garmin Edge 500. It should only be $249. Do NOT get the 200. It doesn't have the barometric pressure sensor. If you can find a good deal on the 800, that would be good too, but its more expensive. It does have mapping capabilities.

Ok, I think the $349 includes the cadence and HR monitors. You can always buy those later.

EDIT:

Edge 500 w/ cadence and HR for $283
Boogerd_Fan

Edge 500 here too... if you can switch it on and leave it on a window ledge finding the satellite before the ride, it should be OK with correct measurements from the start of your ride.

I live in a block of flats, and can only switch it on once outside and away from the tower... after its found a satellite the altitude varies by + - 100m for the same starting point (between 50-150m above sea level)... but by the time i've ridden 20k to the first summit of my usual training ride, the altitude has always corrected itself to cca 400m at the top, give or take a few m...
berck

Boogerd_Fan wrote:
Edge 500 here too... if you can switch it on and leave it on a window ledge finding the satellite before the ride, it should be OK with correct measurements from the start of your ride.

I live in a block of flats, and can only switch it on once outside and away from the tower... after its found a satellite the altitude varies by + - 100m for the same starting point (between 50-150m above sea level)... but by the time i've ridden 20k to the first summit of my usual training ride, the altitude has always corrected itself to cca 400m at the top, give or take a few m...


That's  been my experience too. By the first summit, its very accurate. Although, when I give it time at my house before a ride, mine is about +/- 40ft. My house should be around 330ft, but my readings vary from 290 to 350ft at the beginning. At the return, I find it around +/- 10 ft.
smarauder68

Anybody have a device that actually tells you the gradient as you ride? Is Elevation is nice, but finding an accurate device that confirms my worst nightmares (10% or more) would be fun....

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