Garmin 705 and hill gradients

sampras38

Hi all,

Apologies if this has already been answered but for some reason I couldn't find it. I've had my Garmin 705 for well over a year now and use it all the timr, but until recently I've never paid too much attention to how it calculates the gradient of a hill, as most climbing i've done I've known roughly what the % was.

Lately I've done a little climbing where I have no idea of the gradient % so how do I find out? Even if the formula the Garmin uses isn't completely accurate, surely it'll give me a rough idea?

Do I need to upload to GC to see?

By the way, I have the cadence sensor attached.

cheers

redddraggon

Go into settings and then you can choose how many sets of data you display, and what sets of data - you do all this on the unit itself.

To be totally honest, the gradient is a load of bollox, I've been going downhill sometimes for over 1mile and the reading has displayed 1%, which is bollox. And sometimes I've been going uphill and it's been displaying -1%.

sampras38

redddraggon wrote:

Go into settings and then you can choose how many sets of data you display, and what sets of data - you do all this on the unit itself.

To be totally honest, the gradient is a load of bollox, I've been going downhill sometimes for over 1mile and the reading has displayed 1%, which is bollox. And sometimes I've been going uphill and it's been displaying -1%.

Ahh, cheers. I have used the settings to change things but never noticed one that related to the gradient. Seems like it's not really worth bothering with though by the sounds of it..;-)

redddraggon

It's under "Grade %" I think.

I show 8 sets of data, and I haven't found anything better than Grade % to change to yet.

sampras38

redddraggon wrote:

It's under "Grade %" I think.

I show 8 sets of data, and I haven't found anything better than Grade % to change to yet.

cheers, I'll take a butchers tonight.

DaSy

I find the Gradient fairly accurate when climbing, but seems to be less so when descending. I have always assumed it was due to covering so much more ground between datum points due to the increased speed.

sampras38

The reason I asked the question initially is because I've been doing a fair amount of riding lately with hills around the 8-12% and I was curious as to how the climbs were made up. I do quite a bit around Box Hill as well, and have been using these 8-12's more local to me when I don't get the time to get to Box Hill for the steeper ones. Just doing them 3 or 4 times at different speeds, in/out of the saddle etc.

It just occured to me on a ride at the weekend how steep they really were.

Got some more Alps riding in June and most of the stuff will average out at around the same gradient, but just go on for much longer. Just trying to replicate as much as I can.

waffle waffle...if that makes sense..;-)

DaSy

My advice would be to focus on keeping a high power output for a long time. Lots of short sharp up hills followed by a break to descend etc doesn't replicate the Alps very well.

I rode the Route des Grande Alpes earlier this year, and the best training for this I found to be a time trial type effort of around 1 - 2 hours. The main thing you will encounter is the relentless nature of the climbs rather than the severity of the gradient. Getting used to putting out a reasonable wattage for an extended period works whether on the flat or on a climb.

sampras38

DaSy wrote:

My advice would be to focus on keeping a high power output for a long time. Lots of short sharp up hills followed by a break to descend etc doesn't replicate the Alps very well.

I rode the Route des Grande Alpes earlier this year, and the best training for this I found to be a time trial type effort of around 1 - 2 hours. The main thing you will encounter is the relentless nature of the climbs rather than the severity of the gradient. Getting used to putting out a reasonable wattage for an extended period works whether on the flat or on a climb.

Thanks DaSy.

I'm fairly well aquainted with the Alps and did some last year. Did the Joux Plane 2 times in a week, both times under an hour and the cole de columbiere. Also done a few more and going back in June, most likely Alp Duez and a few of the climbs around that region.

Infamous

redddraggon wrote:

To be totally honest, the gradient is a load of bollox, I've been going downhill sometimes for over 1mile and the reading has displayed 1%, which is bollox. And sometimes I've been going uphill and it's been displaying -1%.

Is it mounted upside down?

DaSy

sampras38 wrote:

Thanks DaSy.

I'm fairly well aquainted with the Alps and did some last year. Did the Joux Plane 2 times in a week, both times under an hour and the cole de columbiere. Also done a few more and going back in June, most likely Alp Duez and a few of the climbs around that region.

Sorry Sampras38, I wasn't trying to be patronising, it's hard to tell experience on the internet...

I'm hoping to do the Route des Grande Alps again next year, but may miss out the Bonnette this time ,in favour of the Cayolle, St Martin etc at the bottom end.

First target is to get my Club des Cingles membership though, hope to do that in June and Alps in July or August.

Casbar

Box Hill is an average of 4% to the best of my knowledge

There are steeper hills around the Dorking area , but they are all short. Nothing I have riden around there can replicate 22km @ 7.5%. Ride harder on the flats in my opinion

sampras38

DaSy wrote:

sampras38 wrote:

Thanks DaSy.

I'm fairly well aquainted with the Alps and did some last year. Did the Joux Plane 2 times in a week, both times under an hour and the cole de columbiere. Also done a few more and going back in June, most likely Alp Duez and a few of the climbs around that region.

Sorry Sampras38, I wasn't trying to be patronising, it's hard to tell experience on the internet...

I'm hoping to do the Route des Grande Alps again next year, but may miss out the Bonnette this time ,in favour of the Cayolle, St Martin etc at the bottom end.

First target is to get my Club des Cingles membership though, hope to do that in June and Alps in July or August.

Oh god no, I didn't take it like that at all.

I'm glad for any advice so no need to apologise.

;-)

sampras38

Casbar wrote:

Box Hill is an average of 4% to the best of my knowledge

There are steeper hills around the Dorking area , but they are all short. Nothing I have riden around there can replicate 22km @ 7.5%. Ride harder on the flats in my opinion

I was referring to all the hills around that region, i.e. some are between 15 and 20% in parts.

sampras38

sampras38 wrote:

Casbar wrote:

Box Hill is an average of 4% to the best of my knowledge

There are steeper hills around the Dorking area , but they are all short. Nothing I have riden around there can replicate 22km @ 7.5%. Ride harder on the flats in my opinion

I was referring to all the hills around that region, i.e. some are between 15 and 20% in parts.

Climbs like Coldharbour Lane, Dorking, Coombe Bottom, WhiteDown etc. Whilst only short and sharp they are great leg warmers and I tend to do most on the same ride of about 60 miles or so. WhiteDown averages around 11% with a max of 19.

sampras38

redddraggon wrote:

It's under "Grade %" I think.

I show 8 sets of data, and I haven't found anything better than Grade % to change to yet.

Of the 8 sets of data you can choose to display, there is one for elevation (this is my usual setting) but the only options I can see are feet or metres, and no % option.

a_n_t

always found the gradient reading to be accurate unless its pissing down!

GavH

sampras38 wrote:

redddraggon wrote:

It's under "Grade %" I think.

I show 8 sets of data, and I haven't found anything better than Grade % to change to yet.

Of the 8 sets of data you can choose to display, there is one for elevation (this is my usual setting) but the only options I can see are feet or metres, and no % option.

You need to look for GRADE as per page 49 of the user manual. It even tells you how it calculates the figure as thus:

"Calculation of rise over run. For example if, for every 10 feet you climb (elevation) you travel 200 feet (distance), your grade is 5%"

In other words, simple trigonometry using the systems ability to measure elevation through its barometric altimeter and comparing that to the distance travelled along the road through either the GPS or the GSC10 sensor unit. I too have noticed that downhill it doesn't seem to go beyond -2% but uphill it's been very accurate over climbs with known gradients. In addition, I used to have a Polar CS600 and it gave the same gradient readings for the same climbs as the 705 does.

fishyweb

In case it helps SportTracks software is quite good for analysing the grades post-ride.

Casbar

sampras38 wrote:

sampras38 wrote:

Casbar wrote:

Box Hill is an average of 4% to the best of my knowledge

There are steeper hills around the Dorking area , but they are all short. Nothing I have riden around there can replicate 22km @ 7.5%. Ride harder on the flats in my opinion

I was referring to all the hills around that region, i.e. some are between 15 and 20% in parts.

Climbs like Coldharbour Lane, Dorking, Coombe Bottom, WhiteDown etc. Whilst only short and sharp they are great leg warmers and I tend to do most on the same ride of about 60 miles or so. WhiteDown averages around 11% with a max of 19.

Have you got that 60 mile ride logged anywhere? If so pls post a link.

Cheers

Cas

sampras38

Casbar wrote:

sampras38 wrote:

sampras38 wrote:

Casbar wrote:

Box Hill is an average of 4% to the best of my knowledge

There are steeper hills around the Dorking area , but they are all short. Nothing I have riden around there can replicate 22km @ 7.5%. Ride harder on the flats in my opinion

I was referring to all the hills around that region, i.e. some are between 15 and 20% in parts.

Climbs like Coldharbour Lane, Dorking, Coombe Bottom, WhiteDown etc. Whilst only short and sharp they are great leg warmers and I tend to do most on the same ride of about 60 miles or so. WhiteDown averages around 11% with a max of 19.

Have you got that 60 mile ride logged anywhere? If so pls post a link.

Cheers

Cas

Couldn't find the 60 but here's a similar one I did on my own. Ignore the maximum speed as the Garmin got it's nickers in a twist.

http://connect.garmin.com/activity/12241087

dave milne

It goes a bit funny occasionally - has read 64% before once but the vast majority of the time it works fine for me

Casbar

sampras38 wrote:

Casbar wrote:

sampras38 wrote:

sampras38 wrote:

Casbar wrote:

Box Hill is an average of 4% to the best of my knowledge

There are steeper hills around the Dorking area , but they are all short. Nothing I have riden around there can replicate 22km @ 7.5%. Ride harder on the flats in my opinion

I was referring to all the hills around that region, i.e. some are between 15 and 20% in parts.

Climbs like Coldharbour Lane, Dorking, Coombe Bottom, WhiteDown etc. Whilst only short and sharp they are great leg warmers and I tend to do most on the same ride of about 60 miles or so. WhiteDown averages around 11% with a max of 19.

Have you got that 60 mile ride logged anywhere? If so pls post a link.

Cheers

Cas

Couldn't find the 60 but here's a similar one I did on my own. Ignore the maximum speed as the Garmin got it's nickers in a twist.

http://connect.garmin.com/activity/12241087

Nice route...I do quite a bit of that normally

sampras38

Casbar wrote:

sampras38 wrote:

Casbar wrote:

sampras38 wrote:

sampras38 wrote:

Casbar wrote:

Box Hill is an average of 4% to the best of my knowledge

There are steeper hills around the Dorking area , but they are all short. Nothing I have riden around there can replicate 22km @ 7.5%. Ride harder on the flats in my opinion

I was referring to all the hills around that region, i.e. some are between 15 and 20% in parts.

Climbs like Coldharbour Lane, Dorking, Coombe Bottom, WhiteDown etc. Whilst only short and sharp they are great leg warmers and I tend to do most on the same ride of about 60 miles or so. WhiteDown averages around 11% with a max of 19.

Have you got that 60 mile ride logged anywhere? If so pls post a link.

Cheers

Cas

Couldn't find the 60 but here's a similar one I did on my own. Ignore the maximum speed as the Garmin got it's nickers in a twist.

http://connect.garmin.com/activity/12241087

Nice route...I do quite a bit of that normally

Yeah, I've done a few around that region and this one is pretty varied. occasionally if I still feel good at the end I'll go past the bikers carpark and continue up Zig Zag road again, doing it one more time.

redddraggon

If the gradient shown on the 705 is accurate I must be a better climber than I thought I was, and that's part of the reason I was doubting the accuracy. I've been hitting 10-13% (according to the garmin) and I've been finding it easy, previously I'd been going off what few road signs show gradient, and those 10% or 1/11 have seemed loads harder.

Another reason why I think the gradient might not be 100% accurate was a test when I first got the Garmin. I walked to Tesco and back, and found that I was dropping in height consistently:

http://connect.garmin.com/activity/19307247

According to that I lost about 35m, even though start and stop position were the same.

sampras38

redddraggon wrote:

If the gradient shown on the 705 is accurate I must be a better climber than I thought I was, and that's part of the reason I was doubting the accuracy. I've been hitting 10-13% (according to the garmin) and I've been finding it easy, previously I'd been going off what few road signs show gradient, and those 10% or 1/11 have seemed loads harder.

Another reason why I think the gradient might not be 100% accurate was a test when I first got the Garmin. I walked to Tesco and back, and found that I was dropping in height consistently:

http://connect.garmin.com/activity/19307247

According to that I lost about 35m, even though start and stop position were the same.

What you might find though is whilst a hill has a sign that says, say 12%, it might be just that a very small part of hill reaches 12 but the bulk is more like 5. The signs are very misleading.

blorg

redddraggon wrote:

Go into settings and then you can choose how many sets of data you display, and what sets of data - you do all this on the unit itself.

To be totally honest, the gradient is a load of bollox, I've been going downhill sometimes for over 1mile and the reading has displayed 1%, which is bollox. And sometimes I've been going uphill and it's been displaying -1%.

That is a fault probably caused by failure of the barometric altimeter, Garmin will replace it under warranty.

redddraggon

sampras38 wrote:

What you might find though is whilst a hill has a sign that says, say 12%, it might be just that a very small part of hill reaches 12 but the bulk is more like 5. The signs are very misleading.

Well this what I'm saying. I've not actually compared 705 to any signs yet. But hills I've done that have be signposted 10% have seemed a lot harder than what my 705 says is 13/14%. Perhaps the signs underestimate in North Wales?

dave milne

I have noticed, when climbing under trees or perhaps by tall buildings the speed shown on the garmin is way lower than it should be and the gradient higher. I assume this is because it's struggling to update from the satellite as often as is optimal

sampras38

redddraggon wrote:

sampras38 wrote:

What you might find though is whilst a hill has a sign that says, say 12%, it might be just that a very small part of hill reaches 12 but the bulk is more like 5. The signs are very misleading.

Well this what I'm saying. I've not actually compared 705 to any signs yet. But hills I've done that have be signposted 10% have seemed a lot harder than what my 705 says is 13/14%. Perhaps the signs underestimate in North Wales?

yeah, sorry, you were.indeed..;-)

a_n_t

You need to switch it on a good half an hour before you ride to let it settle down