Thread: 4X4 Driving and inclines.

Originally Posted by mike_ie

Stock Defender can do in excess of 45 degrees, apparently...

Land Rover Defender Going up the Ramp td4 - YouTube

Nice marketing...

Look closely. The lead up ramp is about 2m high but at least 110 defender length (4.8m) long. Which means it is a lot less than 45 degrees - closer to 25. Also the arch is designed so that the front wheels are over the crest before the rears hit the steepest part.

It has also been shot from a clever camera angle...

I doubt a 90 would be able to climb it though.

I was in New Zealand in 2011. When in Dunedin I drive our Hyundai Getz hire car up Baldwin Street just for the experience.

You really do notice just how steep it is when you are feeling much more of your own weight going through you back than on any other hill. It was kind of like the sensation you get looking up as you ascend the start of a roller coaster. Made me realise that some of the slopes I've driven up off road probably weren't as steep in reality as they looked in the photos or felt at the time.

Even standing on the steepest part feels strange. 1:3(ish) doesn't sound as steep as it feels when you're there.

Originally Posted by isuzurover

Here you go:
Baldwin Street - Wikipedia, the free encyclopedia
World's steepest suburban street is 19*, and appears to be open to 2 way traffic.

So for 18 degrees you don't even need low range...

The steepest brisbane street is 17.4* What Is Brisbane's Steepest Street? Gower Street, Toowong

This is me in my disco having some fun at my bro in law and nephew in their tojos.

Its just my young son filming so not sure what angle he held the camera but it sure felt steep! I know its often not as steep as you think but I would've guessed 45 deg before reading this thread..... i might revise it down a bit now but it was surely over 30 deg...

[ame=http://www.youtube.com/watch?v=BR4vCgV_7S8]Toyota vs Disco - YouTube[/ame]

Who remembers this thread?
I do, And I actually asked about it today.
Now, my GFs father tends to explain things in a roundabout sort of way, he's one of those rambling academic types but a nice bloke
So.
1. He's talking about starting at the bottom of a hill, no run up.
2. He quite willingly admits he could be totally wrong
3. He was convinced by the idea that if a person struggles to walk up an incline then a vehicle shouldn't do that much better.

I showed him the unimog video which he was quite astounded by, although the final one showing 110% incline he dismissed as the front wheels ramp over the end before the rear wheels get to the climb.
What he was essentially talking about was that he believes it is very difficult for vehicles to have a high enough coefficient of friction to scale inclines of a flat surface.
He hadn't considered tyre deflation to increase the footprint to gain more traction, and I reminded him that when us humans walk up things, we're taking one foot off the ground in order to move forwards, so it's not an apples and apples comparison of a vehicle that should be keeping 4 wheels providing drive on the ground.
Add to that, I mentioned that breaking traction isn't necessarily an indication of failure to climb such an incline.
He is also basing this off what he had read, but when he tried it (with a morris moke mind you ) that 15 degrees was the limit.
So, there you have it.
Tombie, time to dust off that 40* hill climb video, and it's time for me to find a suitable hill climb

Originally Posted by Disco Muppet

Who remembers this thread?
I do, And I actually asked about it today.
Now, my GFs father tends to explain things in a roundabout sort of way, he's one of those rambling academic types but a nice bloke
So.
1. He's talking about starting at the bottom of a hill, no run up.
2. He quite willingly admits he could be totally wrong
3. He was convinced by the idea that if a person struggles to walk up an incline then a vehicle shouldn't do that much better.

I showed him the unimog video which he was quite astounded by, although the final one showing 110% incline he dismissed as the front wheels ramp over the end before the rear wheels get to the climb.
What he was essentially talking about was that he believes it is very difficult for vehicles to have a high enough coefficient of friction to scale inclines of a flat surface.
He hadn't considered tyre deflation to increase the footprint to gain more traction, and I reminded him that when us humans walk up things, we're taking one foot off the ground in order to move forwards, so it's not an apples and apples comparison of a vehicle that should be keeping 4 wheels providing drive on the ground.
Add to that, I mentioned that breaking traction isn't necessarily an indication of failure to climb such an incline.
He is also basing this off what he had read, but when he tried it (with a morris moke mind you ) that 15 degrees was the limit.
So, there you have it.
Tombie, time to dust off that 40* hill climb video, and it's time for me to find a suitable hill climb

You said he is a mathematician??? Get him to write out a proof of his theory, and then the engineers on here (Bush65, Dougal, Myself, etc....) can show where he is wrong.

Originally Posted by isuzurover

You said he is a mathematician??? Get him to write out a proof of his theory, and then the engineers on here (Bush65, Dougal, Myself, etc....) can show where he is wrong.

I'll see what I can do.

I know one thing for sure,

I could ride a bike up a hill steeper than I can walk up, (TT250 , DT200 )
(I used to be a member of Amtra, ok ok I wasnt that great a rider - thats why I took up 4x4 instead)

And I can drive up a hill steeper than I could ride up !!

Steep hills most definitely always fell twice as steep as they actually are.
The first time you drive up Billy Goats Bluff you'd swear it was 40deg but its not really that steep at all, (but I guess if your from QLD its steep)

Just to add some data from an experiment I ran in the past. 16 degrees was the point where I could get steel to consistently slide down another steel surface.

I didn't test rubber in the same way. But I'd put a lot of money on it easily beating 18 degrees