The Steepest Hills

Morningrider

Ol'Timer
May 19, 2023
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As a rainy-day exercise I tried to answer the question: where are the three steepest hills in Thailand, according to Google Earth? My nominations are:

#1: 59% at 19.85063,99.06698 on the 1249 from Nor Lae to Ang Khang. The winner.
#2: 57% at 19.21699,98.03487 on the 5035 Elephant Trail The first-runner up.
#3: 56% at 19.85568,99.05691 on the 1249 from Nor Lae to Ang Khang

56 degrees at 19.85568,99.05691 on the 1249 from Nor Lae to Ang Khang.jpg


57 degrees at 19.21699,98.03487 on the 5035 Elephant Trail.jpg


59 degrees at 19.85063,99.06698 on the 1249 from Nor Lae to Ang Khang.jpg


These could be the steepest three hills in Thailand, but there may be others that are steeper that my prospecting did not uncover. There are many hills over 40 degrees, and over 30 degrees is routine, but there are very few hills over 50 degrees, let alone almost 60 degrees. I used to have a Willys M38A1 jeep and its maximum rated slope in low-low 4WD mode was only 70 degrees.

Let’s try to perfect the top-three list. You can use Google Earth to plot the elevation profile of a challenging road to measure its steepest slope (plotting more than about ten km at a time reduces the peak grades, probably due to averaging, so you need to check less than 10 km at a time). Enter the start and end coordinates in the Directions boxes, then right click on the resulting route and click on Show Elevation Profile to see the peak and actual grades. If the resulting route isn’t what you expect, then you have to use Google Maps together with Google Earth. Or you can PM the coordinates of a suspected steep hill to me and I’ll help plot. It’s much easier the second time!

This is just the measurement of the grade of one hill and doesn’t indicate how steep the rest of the road is or how difficult the hill climb is considering the surface, curvature, width, and visibility. For that, you can look at the “Steepest Roads” thread.
 
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Morningrider

Ol'Timer
May 19, 2023
57
42
18
Surprisingly, not even close to the top three:
1. Big Dipper switchbacks, 40%
2. Singapore Road, 35% (they seem steeper because they are so narrow and dangerous)
3. The R1149 Doi Tung switchbacks, 44%

The are all steep roads but as it happens don't contain one really, really steep hill, according to the Google Earth elevation profile. I am not sure how accurate Google Earth is, or their minimum length for a slope calculation, but it probably is more accurate than a consumer-level GPS for elevation.

I checked these before, because my starting point for the Steepest Hills was prospecting in the Steepest Roads list. But there may be a really, really Steep Hill which is not on the Steepest Roads list because there isn't enough of it to count as a road. (For the Steepest Roads I didn't count any road shorter than 5 km.) Maybe around Chiang Dao near the Treehouse. I will have a look tomorrow.
 

Morningrider

Ol'Timer
May 19, 2023
57
42
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Route 1334 Pha Bur switchbacks, 43% max.
Route from the highway past the Treehouse, Chiang Dao, 44% max.

Printscreens from Google Earth attached.

Google Earth insists on drawing the route in dark blue against the green trees which makes them hard to see.
 

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Morningrider

Ol'Timer
May 19, 2023
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Most of the roads on the top half of the "Steepest Roads" list have hills in the low forties. Hills in the thirties are common on narrow back roads, but road signs showing the extreme slopes aren't--they would be everywhere. The much-ballyhooed 3054 is steep but not really steep, but the road is so narrow on the blind switchbacks that you are not going to stay upright if a lorry is coming the other way and you have donkey-box panniers sticking out. Ditto for the Singapore Road.

Unless and until another winner comes to light, we could put up a sign at 19.85063,99.06698, "GT RIDER STEEPEST HILL IN THAILAND," and take a group photo trying to stand up on the 59 degree slope before someone steals the sign or a lorry comes down the hill.
 

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Dodraugen

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Lampang
Interesting! But I wonder what would be the steepest angle an average motorbike would be able to climb?

I remember riding the R4009(?) off the R108 towards Ban Nong Khiaow-Mae Surin waterfall and the Bua Tong flower field - there were some really steep sections close to the R108, I had to (or felt like I had to) lean my body forward as much as possible just to have some ground contact with the front wheel…..

Reminds me of the time I rode up to Mt Bromo in Java-Indonesia. Super steep section, very broken asphalt - people conducting traffic up or down because it was only one way traffic possible due to destroyed road. I was on my loaded Tenere 660 and soon reached the vehicle in front of me travelling at walking pace, impossible to pass due to destroyed road, I couldnt keep riding at so slow speed so I had to stop completely. Braked with front and rear but had a balance problem for a second or two so had to put my right foot to the ground (and thus release the back brake) and backwards I went - faster and faster with front wheel locked until I almost reached the level spot and ended up in the ditch. Scary as f***. I got some bruises and one pannier became quite flat - but it could have went far worse…..

I really wonder how steep that road was and how steep a road its possible to ride with an average motorbike?
 

Morningrider

Ol'Timer
May 19, 2023
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Now you can figure it out. Which route was it? There are several. You can read the start and end coordinates off Google Maps, or mark them on this screenshot with a photo editor:
 

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