Wahoo element bolt

nigelh8991 wrote:

I've just started using a element bolt, which I'm loving. Just have a couple of questions. On the climbing page it displays grade. Is this the same grade that you see on road signs at the beginging of the hill. Also it displays altitude. Is this measure in meters.

Many thanks
Nigel

Yes and no.

The gradient on a road sign will be for the maximum over a certain stretch of road. Your gps should change to show the current gradient as you go over it, but gps can often not be as accurate for elevation depending on how many satellites you are locked into and their position in the sky in relation to you. As for the measurement if it’s like a Garmin for example you can decide if you want metric or imperial measurements so depending which you choose it’ll be meters or feet amsl

mfin wrote:

Trivial poursuivant wrote:

nigelh8991 wrote:

I've just started using a element bolt, which I'm loving. Just have a couple of questions. On the climbing page it displays grade. Is this the same grade that you see on road signs at the beginging of the hill. Also it displays altitude. Is this measure in meters.

Many thanks
Nigel

Yes and no.

The gradient on a road sign will be for the maximum over a certain stretch of road. Your gps should change to show the current gradient as you go over it, but gps can often not be as accurate for elevation depending on how many satellites you are locked into and their position in the sky in relation to you. As for the measurement if it’s like a Garmin for example you can decide if you want metric or imperial measurements so depending which you choose it’ll be meters or feet amsl

The Elemnt Bolt uses a barometric altimeter just like most bike computers, air pressure is measured and changes are how gradient is calculated, a calculation made basically of pressure change over distance.

Sorry, but it seems you are saying the on screen elevation and gradient data comes from gps and satellite data.

Are you sure you're not just making up how you think it works? It certainly sounds like you are.

They still need the gps to work out height. If only I knew someone with 20 years experience in working gps & satellite communications. Oh wait. I do, ME.

Air pressure, funnily enough changes with weather. The computer isn't going to know what the weather is. if it went of pressure alone over distance it would be well off if the pressure changed. An aircraft has a barometric altimeter but it still needs an updated QNH to adjust for air pressure changes in a region. flight levels change and pilots need to alter the measurement accordingly. Maybe not to the same extent but a Garmin, Wahoo etc etc still needs a base reference to know its position on the ground and it uses GPS to tell it. Its not a 2D position you get its 3D. All the barometer is doing is offering minute changes for every little hill or bump you go up or down but if the GPS doesn't account for the actual position any pressure changes will make the barometer think its moving up or down when its not.

The unit still needs to know where it is to make that calculation. Btw. I never said gradient. Just elevation.

redvision wrote:

Trivial poursuivant wrote:

They still need the gps to work out height.

Does it??

A few years ago we were given a barometer clock thing which had also had a range of weather forecast features and a elevation gauge. Only thing it didn't have was gps.

Granted it wasn't the most accurate thing in the world but the elevation was usually within 10%.

10% is just enough to prevent it accidently flying into another barometer clock.

mamba80 wrote:

redvision wrote:

Trivial poursuivant wrote:

They still need the gps to work out height.

Does it??

A few years ago we were given a barometer clock thing which had also had a range of weather forecast features and a elevation gauge. Only thing it didn't have was gps.

Granted it wasn't the most accurate thing in the world but the elevation was usually within 10%.

Disable the GPS and see how far out any elevation data is?

Garmin explained this to me how a poor gps sig messes up the grade display and the elevation, i sent them some activities, they could see the grade was 0% even though the map grade was 10% because the 520 lost gps.......

the Wahoo may be slightly different in that it does more of a compare between the two and then decides which is better IF they are widely different.

Both use a barometer for pressure. But pressure is not a constant. It changes so unless the unit knows where say mean sea level is. Either by manual input or gps it has no idea how high up it is. If it were to stay static but the pressure change even just a few millibars it will think it’s altitude has changed if there is no geo referencing point .i.e a gps signal.

A GPS receiver needs at least 3 satellite signals for a lock. The more it gets the better it can accurately calculate its lat/long position and it’s elevation. Technically 2 satellites will give a reasonable lat/long within 10 meters static but not elevation . More satellites can bring close to 1 meter and better but for that it needs to be military grade with anti spoofing encryption which I work with. Which will allow accuracy inside 1 meter cubed. Enough to fly a rocket or LGBU bomb into a window or air duct. But for cycling around the British Isles 10m is good enough.