Hill gradients

[RichardB]

I've been checking a few local hills on the website mentioned above, and I've found the same. There's a short and very steep section close to home which I need my MTB's 26" low gear to twiddle up, which the website gives a gradient of 11%. There's another hill a mile away which I can do on a 40" gear at a push, and it lists that as 12.5% (I would estimate it to be about 1 in 5 for the same short section). I guess it's expecting a bit much of a remote website to get these things 100% right when the gradient can vary in reality by an enormous amount within a few feet, such as the inside and outside tracks on a hairpin bend. It can only ever be an approximation. Useful, though, and good fun.

 

[PaulSB]

Ooh, didn't know that. Thanks.

My experience is you may not want to know the gradient while you're actually going up!! 😄

As regards the road signage as we have a lot of significant climbs in the area % signs are common. These seem to be placed on roads where the gradient presents a hazard to users rather than as general information.

 

[Mo1959]

My experience is you may not want to know the gradient while you're actually going up!! 😄

As regards the road signage as we have a lot of significant climbs in the area % signs are common. These seem to be placed on roads where the gradient presents a hazard to users rather than as general information.

Think you could be right. I have a sharp one that's around three quarters of a mile and has a 20% gradient sign at the foot. While it is steep at bits, I'm not sure it ever gets to that to be honest. Not sure my legs are up to that these days. Lol

 

[Lovacott]

Thanks to all for the input. I do understand what a gradient is, and as said above I have tried using contours etc on maps but found it to be vague and inaccurate. Roubaixtuesday's link here is just what I was looking for - average and maximum gradients for any given section. Cheers.

A roofers pitchfinder would do it for you.

A simple bit of card with a weighted arrow which points at the centre of the earth. You could tape it to your crossbar. You can pick them up from most builders merchants for nothing (they are promotional material).

 

[Lovacott]

Think you could be right. I have a sharp one that's around three quarters of a mile and has a 20% gradient sign at the foot. While it is steep at bits, I'm not sure it ever gets to that to be honest. Not sure my legs are up to that these days. Lol

Highways departments have stock signs they use and which one they choose depends on what they want you to do after you've seen the sign.

If they want you to go slowly, they'll exaggerate the slope and put in a few skid signs and maybe an escape lane to add effect (A46 from the M4 into Bath is a perfect example).

There are some really safe roads I use which highway signs tells me are deathtraps, and there are treacherous roads I use which don't have any signs at all.

Warning signs pollute our countryside and the only people who seem to take heed of them are the people who wouldn't need to see a sign in order to slap on the brakes.

If I had my way, I'd get rid of all signs and let the road user concentrate on looking at the road ahead.

 

[Ming the Merciless]

There's a hill near me which (according to the signs) is 10% going up it, but 20% going down...

Near Weston

 

[RichardB]

A roofers pitchfinder would do it for you.

A simple bit of card with a weighted arrow which points at the centre of the earth. You could tape it to your crossbar. You can pick them up from most builders merchants for nothing (they are promotional material).

View attachment 549317

Ooh, thanks. I could make one of those. As the Carlton has a horizontal top tube, this would be ideal. No guesswork necessary. Cheers!

If I had my way, I'd get rid of all signs and let the road user concentrate on looking at the road ahead Darwin sort it out.

Fixed that for you.

 

[HLaB]

There's a hill near me which (according to the signs) is 10% going up it, but 20% going down...

Are you sure its not 20% up, 10% down

 

[NorthernSky]

My experience is you may not want to know the gradient while you're actually going up!! 😄

As regards the road signage as we have a lot of significant climbs in the area % signs are common. These seem to be placed on roads where the gradient presents a hazard to users rather than as general information.

true, you'll always be disappointed too. i've been up some crazy hills then you find out it's a measly 10% gradient and you felt you were climbing everest

 

[RichardB]

Well, I downloaded a free clinometer app and it's perfect - exactly what I was looking for. I can stop on a hill (that's the only disadvantage, although I tend to wait until I am on the way down the same hill later in the day) and put the phone on the bike's crossbar*. Clear readout of gradient in 'x in y', percentage, degrees from vertical, arc seconds for all I know. I have it set to % and I now know that a hill near me which is a stiff climb but one which doesn't cause me any nightmares is 10% at the top. That's all I really wanted to know.

* A benefit of riding a vintage roadbike - a perfectly horizontal crossbar. Will have to measure the angles on the other bikes and be prepared for some mental arithmetic.

Cheers all!

 

[PapaZita]

There's a hill near me which (according to the signs) is 10% going up it, but 20% going down...

I suppose it’s possible that the gradient is different on different sides of the road. Hairpin bends, for example, can be particularly steep on the inside of the bend, and almost flat on the outside. It’s also possible that those were the last two signs in stores, and they were reckoned to be close enough.

 

[SkipdiverJohn]

* A benefit of riding a vintage roadbike - a perfectly horizontal crossbar.

Anything else on a road frame just looks wrong!

 

[rj.hr6]

Anything else on a road frame just looks wrong!

 

[Venod]

I can remember gradient signs in North Yorkshire (Sutton Bank and Rosedale Chimney Bank)

I can tell you the gradient of them two of the top of my head, ******* hard.

 

[Pale Rider]

That's all the road user needs to be warned of.

Not forgetting Deceptive Bends.