Most misleading gradient sign

[Ming the Merciless]

as i understand it (which may be wrong) 100% would be 1:1 or 45 degrees.

but what i don't understand is...

Why does 1:5 or 20% feel so steep, when 11 degrees looks like a gentle slope on a protractor?

Because you are increasingly fighting the force of gravity. So it takes a lot more effort to climb a 20% hill than a 5% hill at same speed. If you think about it, climbing a 20% hill at same speed (along slope) as a 5% hill , you’d have to be generating four times the power in your legs, just to climb against gravity.

You can change the gearing and go slower to reduce the effort, but at some point you are travelling so slow that balance gets harder. Then the 24” gear comes out.

If you want to leave Earth’s gravity you need a farking big rocket. Gravity is hard work!

 

[Dogtrousers]

Percentages are per 100 as in per cent. So it’s 35/100 which you could write as 35:100.

Or about a third of a radian.

 

[Ming the Merciless]

Or about a third of a radian.

So this is what you did on audaxes…

 

[Alex321]

I still visualise hills better when written as 1 in 10, 1 in 7, 1 in 4 etc.

I just mentally convert to that.

Not that I see many gradient signs round here in the Vale of Glamorgan. Most of the roads I tend to ride are too small to have many signs.

 

[Alex321]

I cant understand the %age, 35% of what exactly? The ratio 1:3 means something, every 3 units along you go up or down 1 unit, it ain’t a fraction.

1:3 is the same as 33%

You should think of the 1:x as a fraction 1/x, and the % is just the same thing expressed as amount per 100 units (i.e divide x into 100). The % is the number of feet you go up for every 100 feet horizontal.

So
1:4 is 25:100 or 25%
1:6 is 16.66:100 or 16.6%
1:8 is 12.5:100 or 12.5%
1:10 is 10:100 or 10%

 

[andrew_s]

Having checked the OP's Llangollen hill on OS MasterMap, there's a 120.1 m spot height at the bottom junction, a 365.6 m spot height at the top junction, and 1798 m horizontal between, so 13.7% overall average between the two junctions.
Between the 160 m contour and the 260 m contour (just before the sharp LH bend), it's 495 m horizontal, for 20.2%, which is the steepest (almost) 500 m stretch.
The steepest interval between contours is 38 m between the 180 m and 190 m contours, for 26%.

You should think of the 1:x as a fraction 1/x,

The same thing is true of map scales, which many people get the wrong way round: 1:2,500 is a large scale map, and 1:100,000 is a small scale map.
1:2500 is 0.0004, which is larger than 0.00001 (1:100000).
It helps to think of the size of the piece of paper you'd need to map a particular area at a scale.

 

[Drago]

I categorise hills thus...

Flat.
What hill?
Barely.
Gentle.
Brisk.
Stop whittling you wuss.
Steep.
Vertical.
Call the sherpas.
Get me oxygen.
You're having a laugh!

 

[roubaixtuesday]

Having checked the OP's Llangollen hill on OS MasterMap, there's a 120.1 m spot height at the bottom junction, a 365.6 m spot height at the top junction, and 1798 m horizontal between, so 13.7% overall average between the two junctions.
Between the 160 m contour and the 260 m contour (just before the sharp LH bend), it's 495 m horizontal, for 20.2%, which is the steepest (almost) 500 m stretch.
The steepest interval between contours is 38 m between the 180 m and 190 m contours, for 26%.


The same thing is true of map scales, which many people get the wrong way round: 1:2,500 is a large scale map, and 1:100,000 is a small scale map.
1:2500 is 0.0004, which is larger than 0.00001 (1:100000).
It helps to think of the size of the piece of paper you'd need to map a particular area at a scale.

Impressive sleuthing.

So, the challenge stands: can you or anyone else find a more misleading one? By your figures, this averages 50% steeper than signposted for 500m, peaks at double the signed gradient, and averages the signed gradient for over a mile.

 

[craigwend]

I categorise hills thus...

Flat.
What hill?
Barely.
Gentle.
Brisk.
Stop whittling you wuss.
Steep.
Vertical.
Call the sherpas.
Get me oxygen.
You're having a laugh!

You forgot - just no!

 

[Saluki]

I categorise hills thus...

Flat.
What hill?
Barely.
Gentle.
Brisk.
Stop whittling you wuss.
Steep.
Vertical.
Call the sherpas.
Get me oxygen.
You're having a laugh!

I like this a lot Drago, but I reckon that there are 2 gradients of hill, in reality. Those I can ride up and those I can’t.

Currently live in Norfolk so only one real ‘can’t get up’ in my locale, for me.

 

[C R]

I categorise hills thus...

Flat.
What hill?
Barely.
Gentle.
Brisk.
Stop whittling you wuss.
Steep.
Vertical.
Call the sherpas.
Get me oxygen.
You're having a laugh!

Where does "I'll walk the bike" fall in that classification?

 

[neil_merseyside]

Where does "I'll walk the bike" fall in that classification?

Or
I can't even walk my bike it's that steep.