The Steepest Road?

[MidnightRadio]

Last night, I had a dream that I was riding in a car that was driving down a highway somewhere. At one point, we were going down a really steep incline—I mean, really steep. It looked like we were going straight down the side of a cliff. This is the first time I’ve had one of these dreams in a long time. I used to have them a lot as a kid, but it’s been about twenty years since I had one, I’d say.

Anyway, I was wondering: Where is the steepest incline on a paved road and how steep is it? I mean, I know there are mountain paths that are probably very steep, but I’m talking about U.S. highways and whatnot.

Also, how steep an incline could your average automobile drive down safely and with little or no problem?

[GorillaMan]

Hmmm, interesting - I remember seeing a picture of the 'steepest street' in a copy of the Guinness Book of Records many years ago (possibly in San Francisco) - but I can't find it on their website.

[F. U. Shakespeare]

Some claim it's Baldwin St. in Dunedin, NZ, and that wouldn't surprise me.

[wolfstu]

Also, how steep an incline could your average automobile drive down safely and with little or no problem?

Part of it would depend on the speed you drive down it, and how long it is. If you want to maintain a constant speed on a very steep incline, you probably need to use brakes to keep from accelerating, and you may burn the brakes out on a long enough trip (happend to my dad driving in the mountains).

It seems to me, though, that aside from that problem, as long as, looking from the side, a vertical line through the centre of gravity of the car never gets ahead of a vertical line through the front axle, there's no problem.

Until you try to use the front brakes, though... then the situation is akin to going over the handlebars on a bicycle. To prevent that, the braking force must be balanced by the weight of the car behind the axle. Hmm. Depends on car geometry and C of G.

[GorillaMan]

Originally Posted by wolfstu

It seems to me, though, that aside from that problem, as long as, looking from the side, a vertical line through the centre of gravity of the car never gets ahead of a vertical line through the front axle, there's no problem.

I'd have thought there would be a loss of sufficient friction well before that point, after which you're going to start sliding, whether braking or not.

[silk1976]

Originally Posted by GorillaMan

I'd have thought there would be a loss of sufficient friction well before that point, after which you're going to start sliding, whether braking or not.

I agree. I would seem to me that once you get past a 100% grade (a 45% degree angle), the amount of friction on the tires would decrease pretty rapidly because gravity's effectiveness of pulling the tires into the pavement is reduced.

[Trunk]

a house on Baldwin street with the camera tilted

[twickster]

Cool pic, Trunk!

[Antonius Block]

I've seen different claims for the steepest street in San Francisco, but the two most often named are:

2nd St. Between Vicksburg and Church and Filbert St. between Leavenworth and Hyde - At %31.5% grade, these streets share the honor of steepest streets in San Francisco.

from here.

I've driven down Filbert between Hyde (top) and Leavenworth (bottom), and it takes a certain leap of faith. The first few yards going east from Hyde are flat, then you come to the "steep grade" sign but beyond it you just see... nothing. It isn't until you're committed that you can see the road surface because it's such an abrupt gradient shift (it's one of the streets on Russian Hill where long-wheelbase vehicles such as stretch limos occasionally "bottom out").

Wonder what the gradient of Baldwin street is?

[Trunk]

This is by a guy who tried to bike up Baldwin St. It has another picture like the one I posted earlier.

He says it reaches 38% grade and the street was the result of someone planning it with incorrect topographical information.

He also mentions several of the other steepest hills in the world.

[UncleBeer]

Originally Posted by silk1976

I agree. I would seem to me that once you get past a 100% grade (a 45% degree angle), the amount of friction on the tires would decrease pretty rapidly because gravity's effectiveness of pulling the tires into the pavement is reduced.

The static coefficient of friction is the critical thing here. Roughly (heh), the [i]static coefficient of friction is equal to the tangent of the angle at which "breakaway" occurs. Once "breakaway" happens, the static coefficient is no longer of concern; we're now looking at the dynamic, or kinetic coefficient of friction. All this assumes, of course, that your brakes are sufficient to keep the tires from turning. If they're not, then we gotta look at the rolling coefficient of friction. In all of these types of friction, the value of the coefficient is dependent on the materials in contact.

You can find a table listing the coefficiencts of friction between various materials here: http://www.engineershandbook.com/Tab...efficients.htm The static and dynamic values for rubber on dry and wet asphalt and concrete are near the middle of the page.

And here's a pretty good page with some simple experiments you do at home to determine coefficients of friction. Quiz on Friday. Ya know, in case you thought you were just gonna be able to slide easily through this.
http://www.school-for-champions.com/...ctioncoeff.htm

[Antonius Block]

Originally Posted by Trunk

He says it reaches 38% grade and the street was the result of someone planning it with incorrect topographical information.

Before I saw this post of yours, I decided to measure Baldwin St's grade myself using your photo.

Loading the photo into MS Paint, extrapolating the lower edge of the deck and one of the support posts to where they would intersect the curb of the street, and assuming a 90 degree angle where the posts and deck meet, I obtained a grade of 38.0% How pleasant it is when such numbers match up!

[Cunctator]

Originally Posted by F. U. Shakespeare

Some claim it's Baldwin St. in Dunedin, NZ, and that wouldn't surprise me.

I've walked up Baldwin Street. I've also walked up Filbert Street in San Francisco. The street in Dunedin is definitely steeper.

[GorillaMan]

Originally Posted by Trunk

This is by a guy who tried to bike up Baldwin St.

i've been up the Chimney (also described on that page)! Mind you, I wasn't driving, and was making fun of the French runabout being used at the time (I nearly got out and pushed)

[Jeff Lichtman]

According to the CIty of Dunedin's web site , Baldwin Street has a gradient of 1 meter rise for every 2.86 meters of run. This makes the tangent of the angle equal to 1 / 2.86, or about 0.35. Taking the inverse tangent gives an angle of about 19.3 degrees, which is very, very steep. However, the site says only six meters out of the entire street length are this steep. Filbert Street's grade is "only" about 17.5 degrees.

[GusNSpot]

I need to go put as protrasctor to a street in Eureka Springs AR. USA

I think it is a bit steeper than that 19 - 20 degrees. Hummmmm

[Large Marge]

I searched an hour for a web site that lists the world's or even the nation's steepest paved roads, and I found nothing. Nada. Zilch.

Anyone know of a site?

[Antonius Block]

Originally Posted by Jeff Lichtman

According to the CIty of Dunedin's web site , Baldwin Street has a gradient of 1 meter rise for every 2.86 meters of run. This makes the tangent of the angle equal to 1 / 2.86, or about 0.35. Taking the inverse tangent gives an angle of about 19.3 degrees, which is very, very steep. However, the site says only six meters out of the entire street length are this steep. Filbert Street's grade is "only" about 17.5 degrees.

The relevant quote from you linked page says:

Baldwin is recorded in the Guinness Book of Records as the Steepest street in the world, (but there is some dispute over this as only 6m out of the total street length of 30m is at the steepest gradient). Baldwin Street has a maximum gradient of 1m in 2.86m (191). This means for every 2.86 metres horizontal it goes up vertically 1 metre The horizontal length of Baldwin street from North Road to the top of the street is 359 metres. The change in height is 69.2 metres.

I am unable to parse this in a way that makes sense. The high-gradient part of Baldwin must be longer than 6 metres. My post #12 above shows that, at least for the width of this house, the grade is 38%. This surely corresponds to more than 6m of the street length.

I've stood at the top of the Filbert Street grade in SF. Apart from a small horizontal part east of Hyde Street, the entire block from Hyde to Leavenworth is of uniform grade (which is apparently 31.5%). As I said in post #9, the transition from "flat" to "steep slope" is extremely abrupt. When you eyeball it from the top of the slope, it appears to be of totally uniform grade until a couple of metres from the bottom. Walking back and forth around the visual "event horizon", the entire sloping block of roadway appears and disappears in one step. From maps, I estimate the horizontal distance of the slope to be 125 metres, so we're talking about a 40-metre gain in elevation, which is supported by SF Topo maps.

Here is a sideways photo of the relevant block of Filbert St.

[spinky]

Is anyone else skeptical about the description of the guy's tires slipping while simply trying to stay stationary on Baldwin Street? I've ridden up some pretty steep concrete embankments (e.g. the sides of storm drains), and traction on concrete is pretty damn good. And if bike tires couldn't hack it, wouldn't car tires be roughly the same?

[TheLoadedDog]

I have a certain skepticism about this. If the postman slid to the bottom on his arse when there was a frost, surely that would place the entire street off limits to residents trying to get home, as either driving or walking would be impossible.

It's an impressive street no doubt, but I reckon a bicycle could hold still on it.

[whatsittoya]

Originally Posted by ntucker

Is anyone else skeptical about the description of the guy's tires slipping while simply trying to stay stationary on Baldwin Street? I've ridden up some pretty steep concrete embankments (e.g. the sides of storm drains), and traction on concrete is pretty damn good. And if bike tires couldn't hack it, wouldn't car tires be roughly the same?

My impression wasn't that his tires were slipping but that his brakes were. I am a lardass weighing in at over 400 pounds and havn't done much biking lately but I seem to remember from my younger days that while my hand brakes could indeed lock my tires down going forward they would not do near as good a job at keeping me from going backwards. Also he said that he pushed on the pedal to try to stop this backward movement further indicating to me that his brakes not his tires were slipping

[flodnak]

Originally Posted by wolfstu

If you want to maintain a constant speed on a very steep incline, you probably need to use brakes to keep from accelerating, and you may burn the brakes out on a long enough trip (happend to my dad driving in the mountains).

I'm surprised that overheated brakes don't cause more problems on roads like the Troll's Ladder, a popular tourist road in a mountainous area of west-central Norway. This road probably isn't going to break any records for steepness, but it is on a consistently steep incline for a looooong time. Its popularity, alas, extends to tourists who have never driven mountain roads before, who have overloaded vehicles often pulling camping trailers, and who don't know to shift to low gear!

Very entertaining to drive down, but only if you're behind these folks. Being in front of them is not good for the nerves, and there's only two small places to pull over and let them past...

[CalMeacham]

The steepest street I know of -- and I haven't encountered steeper ones, even in San Francisco -- is Third South between 8th and 9th East in Salt Lake City. That block is literally built on a fault line (one block over is Fault Line Park), and it's the one street I couldn't go up by bicycle (It was between my apartment and the University - I used to go one block over on either side, or else walk it up)

[Hoodoo Ulove]

Here's an account, with good photos, of a bicycle hill climb in Los Angeles. 33% is no record, but it's steep.

[flodnak]

There are, of course, alternative ways to get bikes up hills. Like this fine example from my former hometown of Trondheim

It's not an extremely steep hill, by the way - a gradient of about 1 in 5 - but it is soul-sappingly loooooong.

[SmackFu]

I thought the Seattle streets were pretty damn steep right by the water, but apparently the steepest is only 21% grade.

SF is the only place I've seen where the sidewalks were actually stairs.

[Mr. Moto]

I nominate Canton Street, Beechview, Pittsburgh, Pennsylvania.

Cobblestone paving. Stairstepped sidewalk. Grade of 37%.

[chaoticbear]

Originally Posted by GusNSpot

I need to go put as protrasctor to a street in Eureka Springs AR. USA

I think it is a bit steeper than that 19 - 20 degrees. Hummmmm

Hey, I'm in Fayetteville, but don't know where you are.

Aside from that, I'd nominate my road. It's hard to get up in 3rd, and you. can't. do. it. in 4th.

How can we check something like that? I'm serious, guys, I think that I win.

[F. U. Shakespeare]

Several streets in my hometown (Morgantown, WV) have stairs for sidewalks in places.

North Spruce St. stands out -- I recently took a Jersey City-born friend there and she freaked when we drove up it.

[Math geek]Although none of the people responding to this thread have made this mistake, someone posting on one of the linked pages confused % grade (the vertical rise divided by the horizontal run) with the angle between the road and horizontal (the arctangent of the grade).[/MG]

Originally Posted by SmackFu

I thought the Seattle streets were pretty damn steep right by the water, but apparently the steepest is only 21% grade.

SF is the only place I've seen where the sidewalks were actually stairs.

[Bippy the Beardless]

Hardknott Pass in Cumbria, England is often quoted as the steepest road in Europe being 33% it is due originally to them there barmy Romans who liked to build roads straight between their forts.

[casdave]

I've cycled up most of the well known UK steep roads.

The main problem with Hardknott pass is the to reach it from the Lakeland area, you have to ride over Wrynose Pass first, that is a real hard climb, because its 1in4 but its dead straight, with one bend in the middle, mostly 1in5 but the last couple hundred metres are the steep 1in4 bit, just when you think you have nothing left to give it rises up.

Riding up Wrynose Pass, my front wheel was just lifting slightly and skimming the ground from time to time, so when I got down the other side I stopped to put some rocks into my handlebar bag to keep the front stuck down better, since I knew of Hardknotts reputation long before I got there.

Hardknott for the most part is not as hard to ride as Wrynose, even though it is noticeably steeper, because it has a lot of bends on the lower steeper parts and you can swerve a bit to ease the gradient.
When you climb hills as steep as this, most cyclists will zig zag across the road, but the problem comes that as you do so, the sheer gradient can push you into zig zagging back downhill, and no matter what you do, once you are turned downwards, you just cant get it to turn back up again.

Rosedale Chimney Bank is a bit of a monster, when you ride up this one, the first part seems steep, its 1in5, but you soon forget this relatively flat part, because the road just rears up at you.Here again, your problem is that the steep part comes straight at you, you cannot zigzag, you just have to take it as it comes.

If the road is damp and you have high pressures in you tyres, they will lose grip and spin.
I've ridden this a few times, I live within (just) riding distance, to do it you have to jockey ride it, you use your whole body in the process, by bobbing up and down, timing your pedal thrust with you dropping your body a little faster than the pedal stroke, so that you increase your tyre grip on the power stroke.
It looks odd, gets you very hot, but you do not have the humiliation of falling off.

On hills this steep, if you stop, your cycle is at quite an angle on the hill, and your bars are relatively high up, whilst where you feet land is relatively low down, so that to push the cycle you are pretty much carrying the damn thing with your arms almost fully extended.
It makes you have to lean forwards and your feet may easily slip.

One friend with me was trying to ride Rosedale Chimney, but he just ground to a halt, and gracefully tipped sideways, like a great felled tree.
When he eventually landed(somehow the fall seems much further than one on level ground) he didn't stop moving.
The road is so steep, that you literally slide down the face of it, and in my friends case, he was still attatched to his cycle by his toestraps, and every time he tried to reach uphill to the pedals and release his feet, he slid further downhill.

Laugh ? I absolutely pissed myself!

The worst hill I've climbed is the Shibden Wall, its 1in4 buts it's cobbled, and this breaks your tyre grip.

http://www.cyclingphotos.freeserve.c...fondriest.html

Actually there are plenty of nasty cobbled climbs in that area, all are total bas****s to climb, you can feel you bike frame flex under the effort.

Cyclists will tell you that is easier to climb on fixed wheel than gears, which is true, dont know why but fixed wheel is the thing for such specialist climbing challenges.

[Hoodoo Ulove]

casdave, what gearing do you use for these climbs?

[postcards]

Originally Posted by SmackFu

SF is the only place I've seen where the sidewalks were actually stairs.

Ho ho hol, you should visit the Bronx! (And upper Manhattan.)

Entire streets are staircases! (And every damn map shows them as through streets.)

[DMark]

Originally Posted by Trunk

This is by a guy who tried to bike up Baldwin St.

OK everybody, look at that picture...see the house at the bottom of the hill, in direct line with the road?! Can you imagine living/sleeping/going into that house - knowing it is only a matter of time until something comes crashing through the wall at about 148 miles per hour!

It would be my luck to inherit that house from old Aunt Mildred.

[Spectre of Pithecanthropus]

Originally Posted by postcards

Ho ho hol, you should visit the Bronx! (And upper Manhattan.)

Entire streets are staircases! (And every damn map shows them as through streets.)

There's a "Whitley Terrace Steps" near the Hollywood Bowl. Driving by, you just see a masonry wall with a gate in it, over which stands the standard white-on-blue L.A. street sign naming the street. Also, a canyon or two over you can find "Tavern Trail", which is nothing but a very long steep staircase, with apartments and houses alongside. Notwithstanding that these places that are still maintained and lived in, the bottom of this 'street' bears a sign from the city saying that Tavern Trail is withdrawn from public use--probably because it was too steep for the City to want to take the responsibility for it.

[Jeff Lichtman]

Originally Posted by DMark

Can you imagine living/sleeping/going into that house - knowing it is only a matter of time until something comes crashing through the wall at about 148 miles per hour!

Something like this happened near where I live. Moeser Lane in El Cerrito, CA is very steep (not nearly as steep as Baldwin Street, but considerably longer). A fully-loaded asphalt truck lost its brakes near the top of Moeser and made it almost all the way to the bottom before crashing into a house. There was a fire, and the elderly occupant of the house was saved by a passing UPS driver. The driver of the truck was severely injured but survived. The end of the house the truck ran into was almost completely demolished, and the house has since been rebuilt.

The driver had been breaking a local ordinance - the truck exceeded the weight limit for the street by quite a bit. He also broke the laws of common sense - he had no business trying to drive a vehicle that heavy down a street that steep.

[casdave]

Riding hills that steep on fixed I'd use 36chainwheel and 26 sprocket.

On gears though, its maybe 28 or 30 chainwheel and maybe 26 or 28 sprocket.

You can undergear yourself, (26 chainwheel and 32 sprocket - you also risk tearing the hub apart with that low gear too) so you end up pedalling fairly easily(comparitively) but you haven't got the momentum to stay upright and you just wobble off, or wobble in a circle and get forced downhill.

Mountain bikes are hopeless for this type of climb, you can't get far enough over the front wheel because of the position of the bars.Mountain bike bars are fairly high up anyway, and on a hill of this angle they end up even higher, comared to the rest of the bike and you just can't pull on them.

It's odd but track bars are really good, they are so low that they offset the sheer steepness of the hill and end up in a reasonable place to grip.

Balance is a crucial element too, you do end up going so slow that you need to be able to control it, the closest I could describe the handling problem is like riding free standing rollers, and doing it by standing on the pedals and pedallling fairly slow.

[Chronos]

So what's the difference between gears and fixed? I was thinking at first that fixed meant that the pedals were on the same axle as the wheel, like on kids' tricycles or old-style big front wheel bikes, but casdave talks about sprockets on fixed.

[UncleBeer]

Fixed refers to a bicycle with a single pair of gears - the one at the crank and the one at the rear axle.

[UncleBeer]

More accurately - a single pair of sprockets, rather gears.

[Hoodoo Ulove]

Originally Posted by UncleBeer

More accurately - a single pair of sprockets, rather gears.

No, that's just a singlespeed. A fixed gear bike has no freewheel. You can't coast. They have quite a cult. And the front sprocket is more properly called a chainring.

[Spectre of Pithecanthropus]

As a slight aside, when visiting San Francisco I've noticed that the Supershuttle drivers blithely trust their parking brakes on steep roads; they usually make no effort to crimp the wheels or even pull near the curb. Instead, they just leave the van in the middle of the road, pointed upward, and help the person getting out with their baggage, while the remaining passengers grit their teeth--unless they're returning San Franciscans who are inured to the experience.

[Sunspace]

Originally Posted by DMark

OK everybody, look at that picture...see the house at the bottom of the hill, in direct line with the road?! Can you imagine living/sleeping/going into that house - knowing it is only a matter of time until something comes crashing through the wall at about 148 miles per hour!

It would be my luck to inherit that house from old Aunt Mildred.

I think that house may be a gas station.

Not that that makes me feel any more secure...

[Lamar Mundane]

This is by no means the steepest road, but it might qualify for vertical rise vs. horizontal advantage gained - The Moki Dugway in Southern Utah. It rises 1100 ft and you don't move (what seems) more than a couple of hundred feet horizontally. Most intimidating road I have ever driven.

Some photos:
http://imagesoftheworld.org/GrandCircle/Nov26422.JPG
http://imagesoftheworld.org/GrandCircle/Moki005.jpg
http://marina.fortunecity.com/highwater/419/moki.html
http://images.google.com/imgres?imgu...3Doff%26sa%3DN

[UncleBeer]

Originally Posted by Hoodoo Ulove

No, that's just a singlespeed. A fixed gear bike has no freewheel. You can't coast. They have quite a cult. And the front sprocket is more properly called a chainring.

Okay. I stand corrected. Thanks! Sorry for the bogus information, Chronos.

[casdave]

I'm sorry that I didn't explain fixed wheel, not realising that its not all that common to many folk.

Fixed, as already explained, means that you must pedal all the time whilst moving, and it also means you cannot change gear, the one you fit is the one you have.

You'd think this would be a serious disadvantage uphill and downhill, as this is when you select differant gears, but, you can pedal far faster than on gears, and uphill you can ride on a larger ratio than on variable gears.

Specialist hillclimb events, where you have a timed run up some nearby monster, are usually won by fixed wheel machines, the advantage is that great.

Fixed seems to somehow reduce the effect of top dead centre and bottom dead centre, the pedals just seem to roll around so much better.

Add to this that fixed machines have significantly less weight, not having all the rear sprocket cluster and the gear changer mechanisms, a decent fixed wheel machine will lose as much as five or more pounds, and much of the lost weight is rotating weight too, which helps enormously.

I had one super track machine, couldn't have weighed much more than 12 pounds.

Lastly, the chain is in perfect alignment with the sprocket, unlike gears, so you get maximum efficiency, and the wheel construction is very much better too, so you can use lighter wheels(there is a technical reason for this, but I'll leave that out, suffice to say that fixed wheels are stronger than gear wheels)

It is very strongly advisable to use foot bindings, either toe straps or locking shoes on fixed.

[GorillaMan]

Slight bump - regarding streets built with steps instead of a raodway:

Brit Dopers - anyone else see The Lost World of Mitchell and Kenyon on BBC2? I missed the first few seconds, but the introduction was filmed on a 'stepped street' with a Victorian terrace, possibly in Blackburn.

(And FWIW, it's a fascinating programme, particularly if you've any interest in history, or in early cinema, etc. It's based around a huge recently-discovered collection of c.1900 films of everyday life. BBC World / BBC America viewers, keep a lookout for it. )