Gradients

[Bob Culver]

Some time ago the topic strayed to gradients. I mentioned an exceptional driveway in a neighbouring suburb. So today, bored with my usual circuit, and having just converted my 1970s bike from 10 to 15 speed I subjected my aging body to the 50 metre altitude switchback and plodded to investigate. 
A private drive alongside a common 1/5 acre or so section, is constant grade,  and terminates in a platform with a car parked there. I placed my level on the ground and it promptly commenced to slide away! The gradient a staggering 1 vertical in 2.75 horizontal.   This slightly exceeds Baldwin St in Dunedin, South Island, claimed by Guiness Book as steepest in world woth a pinch at 1 in 2.86.
As the platform is on a hilltop close to the sea the sea appears to be the fate of any runaway, strangers driven down must be absolutely terrified and especially if knowingly in a single circuit car. Presumably the car at bottom was not fwd. I wont be trying my  constant velocity Jazz although a hc Seven probably would (up), but the fabric universal would be even more short lived than is now usual. Sevens negotiate Baldwin Street but the exceeding steep part is not prolonged..
The expression of gradients as % is very confusing. It is the tangent x 100, so 45 deg is 100%!! it would seem far more logical if it was 90 deg.

[andrew34ruby]

Bob, how did it go? The newly 15 speed bike. Could you pedal it up?

[Reckless Rat]

This is Baldwin St in Dunedin. It's a tad on the steep side and I wonder how good the handbrake is on that car! (I suspect a cheat somewhere)

[Bob Culver]

I think in the Baldwin St photo there is someone in the car. It is not  fake; have seen other views. And can read the gradient.

For any that might be interested bike gearing is expressed in penny farthing diameter equivalent. Mine was 38 inches  minimum, now 23 inch. As with cars the low gear seems absurd until the grade matches. 
In my aged and generally ailing state I could not sustain even quite modest suburban hills but now can.
Single speed bikes are typically 65-70 but even racing penny farthings were limited to a challenging 56 inches or so, depending on rider appendage.

(The many older readers may be interestsd. Five years ago I became very unfit waiting for a hip replacement. The surgeon did not encourage walking partly because it wears old and new but also because it not very effective unless very brisk. Biking seems to work; I have not got more incapable over 5 years. incidentally living in the city all driving is now a total  bore until far from home. But with miles of dedicated cycleways almost as much fun as the Seven was  55 plus years ago. Many old persons become poor drivers not so much due reduced faculties but much reduced practice. Biking retains alertness and awareness. I have given up trying to induce the speed detector signs to display SLOW DOWN. I concluded that flaking out at 50 kph  may not improve the prospects of reviving the Seven, although could spare forum readers much tedium..)

A few years ago I chatted with a Vintage Austin Register local. He had visited Dunedin and been driven up Baldwin St in a tweaked chummy!
The 1930s Sevens do have a a low gearingt. My sightly tweaked RP would manage the steepest streets in Auckland and Wellington in 2nd. The Wellington road accessed a radio station and the techs were told not to take CA Bedfords as clutches had been damaged. The Auckland road is now down only. Myself and colleagues used to park in it. One recounted how trucks had spilt wet clay and when he touched his car door handle his car and all the others slid slowly downhill!

[Steve kay]

And today's first message from Wales, naturally claims that the road in Dunedin is a blatant forgery and involved jacks and Acrow props, and possibly oak wedges as well. Harlech's Fford Pen Llech has often been acclaimed as the steepest public road, and will one day be returned to that place of honour. Certainly here in South Wales the Valleys provide a splendid range of very steep hills, made more character forming by the reduction to virtual single width by parked cars. I have demonstrated the "side of a house" capacity of the Ruby's bottom gear by ascending Coed Road at Blaenavon. I would never dream of descending it, unless I was lowered by another forumist, and we then photoshopped the safety rope out of the image before posting it.

[Dave Mann]

    Here's a proper car on my local test hill.

[Bob Culver]

Hi Dave
About 1 in 5.5, a little less than my driveway. I understand that 1 in 5 is the max allowed for  new property developments, but must leave the street near flat.... I like that style of house; as aesthetic as the car. The sun does not fade all the car manuals, but the roof is daunting when of smooth corrugated iron as common here..

[Steve kay]

Err, Bob, if it is smooth, then how can it be corrugated? Or is crinkly tin different down your way?

[Bob Culver]

Hi Steve
It is smooth downhill the modern prepainted long run wothout laps and associated rows of nail heads especially so.