Hill % ??

[aml]

Sorry if this is a dumb question, but i've seen a lot of talk on the forums
about triples double and compacts, and you all seem to talk about hills in terms of percentages.
how do you work this out??
i have added a link of the training route that i do. it would be good to know how you work out the gradients.
any help would be gratly appreciated.

www.bikehike.co.uk/mapview.php?id=20905


i will also help me figure out what type of gear set to get when i get my road bike, as i'm on a mtb at the moment. i never come off the big ring, so i assume that a compact will be fine for me.

thanks all

 

[Browser]

As far as I am aware, %age gradient = rise/run or height/length.
So say you are climbing for one horizontal kilometre and in that time you climb 180 metres;

Gradient = 180/1000
Gradient = .18 or 18% (bit steep that )

 

[ASC1951]

you all seem to talk about hills in terms of percentages.

Not all of us. I'm still with the 1:4 etc that I was brought up on.

it would be good to know how you work out the gradients.
any help would be gratly appreciated.
ll

Like this. http://www.ordnancesurvey.co.uk/osw...resources/mapwork/investigatinggradients.html

It's actually a bit more complex than the OS tutorial suggests, because in the real world you cycle along the hypoteneuse, not along the base line.

 

[trustysteed]

click on the Show Elevation data on the right hand side under Mapping Controls and then you can click on the Gradient option in the top half of the screen on the right

 

[Rohloff_Brompton_Rider]

with regards to the gradient screen on bikehike. can someone explain how to read it correctly. if the gradient goes from -5% to +5% does this mean 10% gradient?

 

[trustysteed]

no, it means that at some point on the route you are going downhill at -5% and at some point uphill at 5%

 

[Rohloff_Brompton_Rider]

so from -5% to +5% the line that joins the dots so to speak counts as 5% along its length?

 

[aml]

click on the Show Elevation data on the right hand side under Mapping Controls and then you can click on the Gradient option in the top half of the screen on the right

so does that mean on my ride i have a 20% hill
www.bikehike.co.uk/mapview.php?id=20905

 

[trustysteed]

if you had a line that went from -5% to 5%, it means you would start off going downhill at 5% gradient and then the road would gradually become level before rising to a 5% uphill climb. picture the bottom half of a circle or the letter U. you start off at the top of the left hand side, go down, across the bottom and then climb up the right hand side.

does that make sense?

 

[trustysteed]

so does that mean on my ride i have a 20% hill
www.bikehike.co.uk/mapview.php?id=20905

no, at about 27 miles into the route you have a hill about 13%

 

[Rohloff_Brompton_Rider]

so at approx 18.6 (using the zoom function) you see a negative going to positive which i read (currently soon to be corrected i think) as an approximate 10% climb. have i read it correctly? if not what is the % of climb?

 

[aJohnson]

so at approx 18.6 (using the zoom function) you see a negative going to positive which i read (currently soon to be corrected i think) as an approximate 10% climb. have i read it correctly? if not what is the % of climb?

Just a tiny bit before 18.6 the grad is about 7-8%, Then it drops to about -6 to -8%.

 

[trustysteed]

no, you're not quite grasping the concept. at 18.6 approx, the road goes from a downhill section of 6% gradient to an uphill climb of about 8% gradient.

the graph shows you what the gradient is at any section of the course with 0% being straight and level. so in that section you are going downhill at about 6%. the road then passes through 0% which means that the road has stopped going downhill and has levelled off, it then starts to rise until it reaches a maximum gradient of about 8%. you don't subtract one value from the other to find out what the gradient is. the numbers on the left of the graph tell you what gradient the road has reached at any point during the route represented by the mileage numbers at the bottom.

for example, at about 20 miles you can see a long downward spike. checking the numbers on the left shows that the gradient is about -12% so you're coming down a steep hill.

 

[trustysteed]

Just a tiny bit before 18.6 the grad is about 7-8%, Then it drops to about -6 to -8%.

which means you're going up an 8% hill, go over the top and start to descend an 8% downhill. it doesn't mean you're going down a steep hill of -16%

 

[Rohloff_Brompton_Rider]

ok. so what is going on at exactly 21.1? there's a negative downhill bit, how do you read that?