Member Since: 11 Sep 2006
Location: Swine Town
Posts: 2330
Hill starts on Ice
No, not another IQ draining TV program.
I went and had a 30 minute play in the last snow to practice extreme driving (I'd had enough practice of normal snow and ice). I chose a lane near to me where I knew it was going to be dicey and headed up it.
Click image to enlarge
I parked here because I wanted to practice hill starts on ungritted ice. The picture doesn't show it, but that hill is approx 1:6 and has 3" fresh snow over hard packed snow/ice. I was there for some time!
I have almost new ATRs on the car which have proved unbeatable on the normal roads, much much better than the Zeros on snow and ice (and tarmac and mud and clay and shingle and water and and...).
I tried :
Gentle acceleration, Normal, High-D. Tyres span, no movement.
Gentle acceleration, Normal, High-2. Tyres span, no movement.
Medium acceleration, Normal, High-2. Tyres span, no movement.
Gentle acceleration, GGS, Low-D. Tyres gently span and moved forward about 1", but otherwise no movement.
Medium acceleration, GGS, Low-D. Tyres span harder and car swayed side to side as Traction control shifted power left-right-left-right, but otherwise no forward movement.
Hard acceleration, GGS, Low-D. Only did this once as I didn't want to wear tyres or shock the transmission. Tyres took off at speed with no forward motion, and the car didn't realise it had no grip so no traction control effects either.
Gentle acceleration, GGS, High-2. Tyres span hard and car swayed side to side as Traction control shifted power left-right-left-right, but otherwise no forward movement.
Medium acceleration, GGS, High-2. Tyres span hard and car occasionally swayed side to side as Traction control sometimes shifted power left-right-left-right, but otherwise no forward movement.
Gentle acceleration, GGS, Low-1. Tyres gently span and moved forward about 1", but otherwise no movement.
Gentle acceleration, GGS, Low-2. Tyres gently span and moved forward about 2", but otherwise no movement.
Gentle acceleration, GGS, Low-2, rocking wheel hard left and right. Tyres gently span and car swayed from side to side of the road depending on direction of steering wheel but otherwise no noticeable forward movement. Occasional shouts from traction control.
Medium acceleration, GGS, Low-D, gentle dabbing at brake with left foot. Tyres span gently/hard and car swayed side to side as Traction control shifted power. Dabs of brake caused the car to re-assess what it was doing, and resulted in small leaps forward, followed by slides back. No actual forward movement.
Finally, the working formula:
Gentle repeated acceleration building up a forward/back rocking motion, GGS, Low-2. Tyres gently span and traction control occasionally intervened. Getting the timing right on the deadened GGS accelerator made it tricky, but eventually found the right rhythm and the car rocked forwards/back about eight times and then slowly, gently continued up the hill at which point the traction systems were doing their nuts. After about the 5MPH mark, traction control calmed down a lot and it turned into an easy drive again. Momentum is definitely a friend when going uphill!
When I got to the top I got out and enjoyed the view/air/birds/foxes/isolation for a spell, then turned around to practice my slippery descent driving. I stopped (I still don't believe it could) at the place where I was stuck on the way up, and could see that the tyres never made it down to the tarmac. Each time a tyre had spun it had flicked off the snow and polished the ice underneath completely smooth. There were several tyre diameter polished arches in the road.
Used a mix of HDC and ABS on the way down (preferred HDC to ABS as although going slightly faster, the steering seemed much more precise). No dramas here, though the steering wheel controls seemed to make bu99er all difference to the set descent speed.
Overall been chuffed to bits with the car. Not only has it not put a foot wrong whilst navigating treacherous conditions and recovering other cars from surfaces I couldn't even stand up on, but even when I get it stuck on purpose it still finds a way of getting going without me having to open the bag of grit in the back.
LandRover designers and builders - A big thank you. This car delivers way more than advertised Dr. Ian Malcolm:
"Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should."
Transgenic tomato anyone?
14th Jan 2010 12:35 pm
smaskins
Member Since: 16 Jun 2009
Location: SE London/Kent
Posts: 295
Interesting experiment... how about with traction control off?
Up you go again
14th Jan 2010 12:48 pm
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This made me smile as I did a similar test the other day The hill I stopped on was a bit steeper though, at the point I did it (I found the steepest bit ), it was probably a 1:4-5
The rocking motion definately is the way forward to get enough momentum to keep going, but once going, unbeatable!
ISTR I used GGS High 2, but it might even have been just GGS High D.
Coming down the same hill I use HDC as it is soooo much smoother drive down than braking
Oh, I also tried it in Sand mode DSC off just for fun and that was interesting as I just slid backwards Bodsys Brake Bible
HDC? Screw that. GGS Low 2 (Low 1 if really bad but be prepared to knock it into 2 if you start to slide under engine braking as acceleration in Low1 is far from smooth, even with GGS on) and take it down on (or off) the throttle as you see fit. More chance you can maintain steering and use hedge/ditch/bank if it all goes Pete Tong than if you use brakes or HDC.I know it's not considered "kind" to say no these days, but no. Just no, ok? And if it's not ok, still no.
14th Jan 2010 1:37 pm
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14th Jan 2010 1:42 pm
simon
Member Since: 11 Jan 2005
Location: Shropshire
Posts: 18296
Did you try holding the EPB switch up for a few seconds before moving off ?
This sets the EPB to only release when it deems there is enough rev action to pull you up the slope. Hill start mode effectively.
Its far better than it releasing as soon as you squeeze the go peddle.
Seems to help when pulling away on slippery slopes.
I think the main issue was your polishing the road with repeated tries though. Reversing back a bit each time may have helped - assuming you have road space to do so of course.
14th Jan 2010 2:34 pm
Bodsy Site Sponsor
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Not Tried that one Simon, will give it a go when I get the chance Bodsys Brake Bible
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14th Jan 2010 2:45 pm
simon
Member Since: 11 Jan 2005
Location: Shropshire
Posts: 18296
It may on MY2008 onwards though from memory...
14th Jan 2010 2:46 pm
DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
i did a similar experiment. went up a 3 in 1 slope close to home with about 7cm of snow on top of ice
High ratio, auto, normal TR.
pulled away without any problems or wheel spin
but then I had "Proper" tyres on
is it worht doing a night event down wiltshire way, or is it all melting Duncan
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3 in 1 best I ever managed was a 1 in 3 must be hellish tyres Club Pie n Pea
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You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
), it was probably a 1:4-5
best I ever managed was a 1 in 3 must be hellish tyres 
