Max hillclimb degree

[KZN KZTE]

I had a discussion with a pal who recently bought a 4x2 and took it on his 1st trip to the bush and afterwards sent me some pics of a 45 degree section he went up.
I told him rubbish it was not 45 at all.
That made me think - what is the steepest hill a standard vechile can go up? Not a pipecar!
Is there some law of nature stopping you at a certain steepness?

[Family_Dog]

A 45° hill is a ratio of one to one, so my guess is that would be the absolute maximum you could hope to climb. However, my assumptions are usually wrong so someone like Hoppy could hop in and correct me.

I'm referring to a hill climb rather than a short vertical stretch where momentum will probably get you over the top.


-F_D

[KZN KZTE]

I also heard the 45 max story somewhere, but you do make a good point separating the hill climb from the short vertical stretch.
Maybe someone can give an answer to both??

[Mr_B]

Pierre... I happened to look at the pics at your link in the signature... neeeeee man... recovering a Hilux off the pavement... with a Range Rover of all vehicles... nee man... not cool...

It's time for a minor suspension upgrade on the KZTE!

[Mud Dog]

The 45° climb is easily do-able without momentum in L4 as long as you've got grip. (Even with a 4Y).

[rock solid]

if u get on some of the rock climbs over here, the rock is called slick rock, has the surface of sand paper. alot more of an angle can be climbed

[Mud Dog]

I recall seeing that same rock spur (or one just like it) in a documentary where a guy in a Bronco lost brake control coming down ... even though he tried using the gears to control his speed, he ended up going too fast, bouncing and went off the side at the very bottom. Lucky to come away with minor injuries.
But yes, steeper angles are possible, but I was talking IRO a standard 2.2lit Hilux.

[Spartan]

Is there some law of nature stopping you at a certain steepness?

Yes nature will stop you until you adapt, go read about the dwarf mammoth's of the Galapagos island Look at my first picture below I went down and back up on that angle.

[CasKru]

I recall seeing that same rock spur (or one just like it) in a documentary where a guy in a Bronco lost brake control coming down ... even though he tried using the gears to control his speed, he ended up going too fast, bouncing and went off the side at the very bottom. Lucky to come away with minor injuries.
But yes, steeper angles are possible, but I was talking IRO a standard 2.2lit Hilux.

It was actually a lady driver out on her first 4x4 drive and she lost control (according to Destroyed in Seconds on Discovery channel)

The maximum incline a vehicle will be different to every vehicle. Taking grip and power out of the equation the only factor that has an influence is your centre of gravity. Strictly speaking you would be able to drive a std bakkie (lower) up a steeper incline that a 4x4 with raised suspension. You would probably be able to do a 55deg incline (remember grip is not part of the equation at this point).

Practically speaking you will need a large capacity engine with enough torque and loads of grip to get you up inclines above 45deg. The max I have done (hill climb and not short steep wall) is about 43deg and believe you me, you want to pinch washers. The problem with this sort of incline, if anything should go wrong, it goes horribly wrong.

Here is a video of a Prado doing a 43deg climb. Not only does it climb it, it stops and starts forwards and backwards at this angle and this is a heavy vehicle.

[KZN KZTE]

Thanks for the video clip CasKru - nice!
Maybe that is a confirmation - If the guys marketing the Prado thinks 43 is worth advertising in such a big way then surely 45 is like the ultimate.
You probably could go steeper but ALL conditions must be right.

Thanks for the input.

PS: RustyRod - The KZTE is my everyday car (and only a 4X2) so I don't want to do any mods to it that would negativly impact on consumption or handeling. The Rangie is my play vechile :)
See the full post on the funny recovery here:
http://www.4x4community.co.za/forum/sho ... hp?t=35028

[ThysdJ]

Traction and torque are the main ingredients for climbing steep hills. With enough traction and enough torque there is no reason (besides the centre of gravity that could topple the vehicle over) why a vehicle cannot climb steeper than 45 degrees. As Cassie says though, if things start going wrong at those angles they go wrong in a big bad way, and reversing down any kind of extreme incline like that usually end up in tears.

The first question I ask myself when faced with a steep incline is "Do I really want to reverse back down if I dont make it to the top?"... The other thing is also this, your vehicle wont run out of steam near the bottom where it is still easy to reverse down, it will stall almost right at the top. So once you're committed, you have to go all the way..

[KZN KZTE]

So once you're committed, you have to go all the way..

Well said Kaspaas!

[ThysdJ]

If things start going wrong they go wrong in a big way. These guys were extremely lucky not to roll over.

[CasKru]

Here is that same rock with a Prado doing it:


I tried it as well with my bakkie when I still had a carb which ran dry 3/4 up the incline and had to reverse down. This can be seen at the end of this video(8:47):

[KZN KZTE]

Cassie - at 9:21 on your video I would have stained my seat in a big way!!!

[CasKru]

Cassie - at 9:21 on your video I would have stained my seat in a big way!!!

That was probably the worst part about the whole climb.... :shifty: :shifty: :shifty:

[ToyX4]

I captured a still just before Cassie went back

[Mud Dog]

Cassie, Can you remember if you came back down on brakes only (looks a bit like that in the clip) or did you put it into reverse even though the engine was dead to lock the front to the back wheels and run against compression as well?

[Mud Dog]

Check this one out ......


http://www.youtube.com/watch?v=rY1QBtyus8E

[2.8 d/cab SFA]

lets go gerotek next year and find out, landcruisers went this year

[CasKru]

Cassie, Can you remember if you came back down on brakes only (looks a bit like that in the clip) or did you put it into reverse even though the engine was dead to lock the front to the back wheels and run against compression as well?

Hey Andy... it ran back only on compression. The video had a sound track but it seems that youtube cut it out due to copyright etc on the sound clip. But if it was still there you would have heard the bakkie running out of steam, stalling and then me keeping it on the brake, putting in reverse and cranking it. I usually keep my foot in the brake to slow things down should compression not be enough

[CasKru]

Check this one out ......


http://www.youtube.com/watch?v=rY1QBtyus8E

Okay... but with this one you can really take the degrees into account as it is short and steep. With this sort of thing you could do angles of up to 90º if not to high.

[DOELLOOS]

Dit klink soos 'n challenge...


Cassie se dis maklik om dit te doen...

[CasKru]

Dit klink soos 'n challenge...


Cassie se dis maklik om dit te doen...

Ek het al soort gelyke goed aan gepak (miskien nou nie heeltemal soos die een op die video nie maar verseker hier by die 70º rond)

[Mud Dog]

Ja nee ..... it would of course be nice to have a second vehicle for this type of thing that you don't mind bashing about .... and if it gets to the point where it's no longer street legal (not too difficult to achieve here in SA), a nice little flat-bed to cart it about.

I would'nt put the 'Dog' through anything too damaging, and I suspect that most of us use our 4x4's as (semi)daily runners, so we never really get into some of the more extreme stuff. A pity in the sense that we lose out on that extra experience.