Hill gradients and OS arrows

suze · May 2007

I went out for a ride yesterday, to test my new compact chainset. I'd planned a route around Scammonden dam, from Rochdale. At home latter I got to thinking. On the OS map it show 1 arrow, ie 1 in 7 to 1 in 5. The hill must have been at least 1 in 4 and probably steeper on the bends. Well as someone who use a 39 chain ring for the past few years and got up most things, I was thankful for my new lower 36

Does anyone know how often the OS grade hills. Do they use an average gradient method and if so over what distance do they use. ie do they take an average over say 20 metres.

Or do they grade hills being that of the steepest part of the hill.

Still got sore legs.......

œ3 grand bike...30 Bob legs....Slowing with style

Jaded · May 2007

My steepest hill near me doesn't have a chevron on the OS map, where much more benign ones do. I think it is a bit arbitrary.

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[Warning] This post may contain a baby elephant or traces of one

mossycp · May 2007

I don't actually know but I would assume that it is actually a mixture i.e. a maximum average gradient. What sort of distance they measure over I don't know but I do know that very few hills are marked at 1:3 or 33%, however, quite a few hills do have short bits that are 30-35% but are marked at 1:4 or 25%.

How do you know that it was "at least 1 in 4"? It would be very difficult to guess and 1:4 or 25% is VERY steep. 1:5 or 20% which would warrant a single arrow is still VERY steep. Unless you have an accurate altimeter or inclinometer I doubt you'd be able to tell the difference between 1:4 and 1:5.

<h5>Today is your day, your mountain is waiting, so get on your way {Dr Seus}</h5>

Unknown · May 2007

I just hope that the Ordnance Survey don't employ cyclists to assess gradients given their tendency to hyperbole!

"Then we did a four mile climb and it was 1 in 4 all the way!" [;)]

suze · May 2007

How did I know....well... I there are steep hills and ...well this one was B*****Y steep hill....therfore this one it's gotta be steeper than steep....

Oohh and it was about twelvety miles long.....

œ3 grand bike...30 Bob legs....Slowing with style

mossycp · May 2007

I'll try and find it on Tracklogs tonight, see what that says

<h5>Today is your day, your mountain is waiting, so get on your way {Dr Seus}</h5>

Tom Butcher · May 2007

I really really doubt it was at least 1 in 4 and steeper on the bends - the only road steeper than 1 in 4 I've been up in the UK is a stretch of Hardknott Pass and anything that was 1 in 4 with steeper sections would be a very well known climb. Winnats Pass is only 1 in 5.

Dave Hinde - probably the worst bike shop in the world.

mossycp · May 2007

According to Tracklogs the average gradient over the whole hill is about 12%. That's over a distance of 0.4 miles. The bottom bit seems to be the steepest at an average of 16% over 0.2 miles. The maximum gradient I can get is 20% over a distance of 0.01032 miles (0.1661km)

<h5>Today is your day, your mountain is waiting, so get on your way {Dr Seus}</h5>

freddered · May 2007

Everywhere between Huddersfield and Oldham is too lumpy for me. It looks like the OS Maps people dropped a box of Gradient-Chevrons on it.

My experience is that front wheels start lifting and rear wheels start spinning much beyond 1:5.

However, anyone local to Huddersfield probably has a genetic ability to cycle up steep hills.

Chris James · May 2007

In which case my Chester born genes must be letting me down.

There are one chevron roads all over the place arund here. And the ones with no chevrons are pretty steep too. In fact it is not the steepness that gets me, but the unremitting nature of it. The tireder I get, the steeper the roads seem too!

Having said that, a double chevron road is REALLY steep and pretty unusual.

fossyant · May 2007

Winnats.... ohhhhh ! Only tackle this with others - get the motivation. It's an average gradient, so some bits will be nasty on any climb the last third is real nasty, the bit from the cattle grid at the bottom is ok until the body dies. I've done Winnats on a 41 x 21 - but my age is now telling me this is no longer possible old man (37) - I always used to say anything was possible on a 42/21...errrrmmmmm yeh 15 years younger and stoopid maybe... It's always great to get up a nasty climb, even if zig zagging is needed in between cars passing !

I'm slowly joining the 'pedal up it' brigade and get a reasonable cadence going !

yenrodcp · May 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by suze

I went out for a ride yesterday, to test my new compact chainset. I'd planned a route around Scammonden dam, from Rochdale. At home latter I got to thinking. On the OS map it show 1 arrow, ie 1 in 7 to 1 in 5. The hill must have been at least 1 in 4 and probably steeper on the bends. Well as someone who use a 39 chain ring for the past few years and got up most things, I was thankful for my new lower 36

Does anyone know how often the OS grade hills. Do they use an average gradient method and if so over what distance do they use. ie do they take an average over say 20 metres.

Or do they grade hills being that of the steepest part of the hill.

Still got sore legs.......

œ3 grand bike...30 Bob legs....Slowing with style
<hr height="1" noshade id="quote"></blockquote id="quote">

Why oh why get a compact chainset talk about the biggest waste of money ever !

I just couldn't seem to get the gears...spun out etc...!

Theirs 3 'bugger hills' in my locale within say 15mls - Ive found in 15yrs of cycling that even if you have say a 24/28t you still have to pedal the dam thing and Ive been up a plenty steep hill in Wales and even then that turned into a one pedal push / one pedal push pedalling style...

So you''ve still gotta push the bloody pedals what ever gears you've got. ! [:0]

[;)] 'tuono nel mio cuore...[:)]

binlinus · May 2007

"A road gradient takes the form of either a single or double arrow marked in
black on the road. These represent a gradient of 1 in 5 or steeper (A) and a gradient of between 1 in 5 - 1 in 7 (B) respectively. They are a way of showing 'sudden' changes in gradient along a road, a steeply dipping/climbing section of the road."
http://www.scoutingresources.org.uk/mapping_contour.html#spot

Bin

ColinJ · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by suze

I went out for a ride yesterday, to test my new compact chainset. I'd planned a route around Scammonden dam, from Rochdale. At home latter I got to thinking. On the OS map it show 1 arrow, ie 1 in 7 to 1 in 5. The hill must have been at least 1 in 4 and probably steeper on the bends. Well as someone who use a 39 chain ring for the past few years and got up most things, I was thankful for my new lower 36

Does anyone know how often the OS grade hills. Do they use an average gradient method and if so over what distance do they use. ie do they take an average over say 20 metres.

Or do they grade hills being that of the steepest part of the hill.

Still got sore legs.......
<hr height="1" noshade id="quote"></blockquote id="quote">
Hi Suze.

Ah Deanhead - it's nice round there!

I did that climb a couple of times last year, and rode down it with Warburton a few weeks back during a heavy shower. Yes, it is steep, but my 'Can I climb it sitting down?' and 'Am I scared riding down it in the rain?' tests tell me that it isn't 25%. Last year I did Fleet Moss from Hawes, Park Rash and Mytholm Steeps (details here), all genuine 25% climbs, and there was no way I'd get up them sitting down. I did manage to get up Deanhead in the saddle.

The 'Could I take part in a heated debate about gear ratios on that climb?' test (no, I couldn't!) tells me that it is significantly steeper than 15% so I reckon 20% is about right.

Why is that every time I try to do steep, narrow climbs like that, the only car for about 30 minutes suddenly comes bombing down the hill towards me and forces me to start again [:(]?

No, Man is an island!

ColinJ · June 2007

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by suze

I went out for a ride yesterday, to test my new compact chainset. I'd planned a route around Scammonden dam, from Rochdale. At home latter I got to thinking. On the OS map it show 1 arrow, ie 1 in 7 to 1 in 5. The hill must have been at least 1 in 4 and probably steeper on the bends. Well as someone who use a 39 chain ring for the past few years and got up most things, I was thankful for my new lower 36

Does anyone know how often the OS grade hills. Do they use an average gradient method and if so over what distance do they use. ie do they take an average over say 20 metres.

Or do they grade hills being that of the steepest part of the hill.

Still got sore legs.......

<hr height="1" noshade id="quote"></blockquote id="quote">
That's why I use a triple. It's a 30/28 bottom gear for me on anything over about 15%, unless it is short enough to use brute force on. Danillo di Luca used a 34/29 on the Zoncolan stage of the Giro, and I'm pretty certain I can't climb like him [;)]!

No, Man is an island!

Steve I · June 2007

There's a virtually unknown and unmentioned lane running from the village of Trefriw near Llanrwst in North Wales, it leads to the Llyn Cowlyd reservoir. Climbing 420 metres in 1.88 miles and starting at about 10m above sea level right in the village, it tops out at 430m before descending to the reservoir. It's really awesome, as you climb it seems like you're climbing into the sky, that's if you can climb it of course. As far as I'm aware there's nothing in England to match it, it's a tougher climb than the much more famous Bwlch y Groes near Bala.

Chris James · June 2007

I have driven up a lane around there on the way to a car park to climb Amphitheatre Buttress. Maybe its the same one? Even if not, it probably has a simliar profile to the one you are talking about. My car was virtually glowing by the time I got up it, so I took it to mean that it was steep!

clc2005 · June 2007

Chris

If you have climbed Ampetheatre in the Carneddau then you would use the road up to Llyn Eigiau from Dolgarrog. The roads/tarcks round that area are very narrow and very steep!

Steve I · June 2007

Yeah, I did the Llyn Eigiau climb after the Llyn Cowlyd climb, it leads to a small car park not far from the Llyn Eigiau dam. The Llyn Eigiau climb is steep in places, but it's well easier than the climb from Trefriw (much less height gain). Both are well worth the drive to tackle if you like hills. Probably better done using a mountain bike as there's some exploring to be done at both reservoirs and it's not road bike terrain.

RichardD · June 2007

How does the climb from Egton Bridge (not far from Whitby) south-west up to the moors rate? There's several other roads up the side of the valley there which match it for the initial steepest section (at least one was marked as 1:3), but I had to take that one all the way to the top.

Hill gradients and OS arrows

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