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Inexpensive computer for stoker - basic functions only

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jul:
I've seen a model that i like , it's the "VDO M4 WR"
https://www.rosebikes.com/article/vdo-m4-wr-bike-computer-wired/aid:715346

I"m interested with this one because it have an altimeter and it can  use with wire (not wireless)

However, i have a doubt about the altimeter ..

Do you think it is a good option and is it really reliable ?

David Simpson:

--- Quote from: julio on October 11, 2016, 01:16:57 pm ---I've seen a model that i like , it's the "VDO M4 WR"
...
However, i have a doubt about the altimeter ..
Do you think it is a good option and is it really reliable ?

--- End quote ---

I have the VDO MC20 WR, which also has the barometric altimeter.
     http://www.vdo-mc2.com/en/functions

I have found the altimeter to be quite accurate. My commute is about 13km, and the first 4km of my commute has an elevation drop of 150m. When I get home, the altimeter is normally within 1-2m of what it was when I left home.

The problem with barometric altimeters is that they sensitive to air pressure changes due to the weather changing. If the weather changes during the day, the altimeter can be off by 5-10m at the end of the day. The MC20 has 2 "home altitude" settings. I set one to my home elevation (153m) and the other to my work elevation (10m). At the start of each ride, I reset the altimeter to the appropriate "home altitude", so the altimeter is fairly accurate for the duration of that ride. For a longer (multi-day) ride, I would want some way to reset the altimeter each morning, especially if the weather is changing.

As for whether an altimeter is a good option, that is a personal preference. I am the kind of person that likes numbers and measuring things, and I live in a mountainous area, so I like the altimeter.

- DaveS

jul:
Ok Dave,

However, if i ride each day in differents places, and i don't know about the altitude where i am..

Is it necessary to reset in this situation ?

Or is it preferable to reset when i know exatly the altitude where i am ?

David Simpson:
No, it is not necessary to reset the altimeter, but if the weather changes, the altimeter could be off by 5-10m. The altimeter never NEEDS to be reset, except when you first install it.

I would only reset it when you know the exact altitude (to within 5m), since the altimeter will probably be within 5-10m anyway.

- DaveS

jul:
Thank you ! 

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