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2006 gmc envoy_sle_xl
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Discussion Starter #1
I found that trying to go up a hill, I had to spin forward a short way, back up just a little, and then forward again. Kind of like rocking it forward and back. This was on dirt with about 3" of snow.

What I found was that when I would step on the brake just as I was stopping forward movement, the anti lock would kick in, and I would start rolling backwards and not be able to stop! It got to be real pain in backside! It was slippery, and I know it would slide a little, but I also know from my off road experience in older vehicles, it would have stopped much quicker without the anti lock.

I had another time I was going down a really steep hill that was grass and weeds in an open field. Just after going over the top there was a bump that caused the front end to lighten up. (imagine one of those large speed bumps on residential streets, about 10" high and about 4-5' across) Well, as steep as the hill was, once some weight cme off the front wheels, they wanted to skid a little. Anti lock kicked in, which had the effect ofletting off the brakes, so we sped up, making the back end hit the bump faster, making it want to give even more anti lock! The end result was the pedal going almost to the floor, and practicaly free wheeling all the way down the hill! It was a little disconcerting, especially since at the bottom I had to make a sharp right hand turn onto the road, or else go over a very sharp drop off! I was just barely able to keep it on the road. Now, with no anti lock system, I could have locked up all the wheels, and it would have slid about 6-8' and stopped. Again, I know from other vehicles.

Is there a way to disable the anti lock system while off road?
 

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2004 chevy trailblazer_lt
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I ran into the same thing Saturday when I was up playing in the snow. I was coming down a icy hill, and wanted to slow down, apply brake pressure and nothing happens, I can hear the anti-lock system doing its thing, and the pedal pushing back at me, but there was no actual stopping going on, So I just threw it into 1st, let the engine brake me.

On a older rig, I know when the tire will break lose, and I know how do gain traction after that happens, but the Anti-lock doesn't want to give break power to a tire that starts to slip, so on ice it seems to hardly apply the brakes at all....
 

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2005 chevy trailblazer_lt
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As long as you stay in control, its no biggie. If I'm going down a grade, engine braking and low gear really helps. Meaty tires also help greatly because it allows your tires to actually grip when braking.

But yes, once in a while it seems like its taken me longer than I expected to stop due to loose dirt/rocks. ABS is still better because you retain steering control. If your tires lock up, you have zero steering control. If in a tight spot, I'd rather steer away from a tree and stop a little further down the hill, than stop because of the tree.

Just a thought.
 

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2004 gmc
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I haven't gone so far as to pull the fuse to disable the ABS, but that was going to be something to consider. One slippery uphill in the Sierras this year, I failed to carry enough momentum at the end of a 20-25 degree hill to get over the lip to the flat part on top. I slid backwards, ABS on dusty gravel gave me zero braking power, and Teebes was coming up fast in the rear view mirror assuming I was going to make the lip. I turned just a little so I wouldn't trigger a roll-over, and went just off the trail and stopped before I hit him. We could have both been disabled at 11,000 ft. elevation. :x

Downhill, if it's steep, I'm almost always in 4LO, and engine braking in 1st gear is so effective I almost never need to touch the brakes even with 25-30 degree downslope. Sand, rocks, doesn't much matter. Then all 4 tires are pretty well doing equal jobs, assuming traction is equal among them. On a rutty downhill (see recent video on Youtube), compression braking works even when you have one or two wheels in the air. An intelligent traction control system could deal with that, but not our dumb stock ABS.
 

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2006 gmc envoy_sle_xl
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Discussion Starter #5
Yes, I do use 4LO normaly. This time I was in HI because it had all been flat ground. This was the only down hill, and it was about 100' long. It is a field where I have gone shooting for years, and have never had a problem on this hill. Of course, I was always in my '78 GMC truck or my '84 S10. Both with no ABS. Both of them would have gone down that hill just fine that day. I did put the Envoy in 1st, but it does not hold back much in HI.

ABS is still better because you retain steering control. If your tires lock up, you have zero steering control. If in a tight spot, I'd rather steer away from a tree and stop a little further down the hill, than stop because of the tree.
I agree, under most conditions. However, in this situation, my point is that without ABS I guarantee I could have stopped in just a few feet. But with it, it was almost like no brakes at all. I was going faster and faster all the way down.


Oh well! Lesson learned! Beware of the ABS offroad! :cool:
 

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2004 chevy trailblazer_ls
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Happened to me yesterday!

I was up in the Mountains( on the road) and needed to turn around so i pulled over onto a Muddy Turnout, but when i pushed the brakes the ABS kicked in and i could barely stop.

Also happened a bit when i was playing in the snow and Mud.
Its really Irritating.

Would it be possible to hook up a switch to the ABS, so that when you go off-roading you can turn it off. Could that have any Damaging effects on the vehicle(not including when you lock up and crash):D
 

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2003 chevy trailblazer_lt
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Would it be possible to hook up a switch to the ABS, so that when you go off-roading you can turn it off. Could that have any Damaging effects on the vehicle(not including when you lock up and crash):D
i have thought bout this myself... could be done.. simpliest way is to rig up the fuse with a switch... switch is on.. the fuse is connected and abs works.. switch is off the fuse is disconnected and abs is off...
 

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i have thought bout this myself... could be done.. simpliest way is to rig up the fuse with a switch... switch is on.. the fuse is connected and abs works.. switch is off the fuse is disconnected and abs is off...
I think im going to have to look into that.:undecided
 

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I think im going to have to look into that.:undecided
yea.. easiest and fastest way if u insist on it... i need u to sign a wavier before u do this tho.. lol and let me know how it works out cause it would be useful...

cause i havent tried this yet... havnt had to... but since i have no locker.. if u hold the brake and hit the gas to try and equalize the wheel movement.. wouldn't the ABS kick on also..
 

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2006 gmc envoy_sle_xl
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Discussion Starter #10
cause i havent tried this yet... havnt had to... but since i have no locker.. if u hold the brake and hit the gas to try and equalize the wheel movement.. wouldn't the ABS kick on also..
I think it may depend. If you are not moving very fast, or most likely, not at all, then I don't think it will. I am pretty sure the ABS reads info from all 4 wheels as well as knowing what you are doing with the throttle and brake pedal, and how fast you are going. So if you only have one or two spinning, then the traction control should actually kick in, and try to stop the spinning wheel/s. This actually doesn't work too bad. I have the rear locker in mine, but I have had a few times where I had one front wheel off the ground, and the rears started slipping, and I could tell that the traction control kicked in and tried to stop the front one from spinning, giving the one on the ground some power. It is not as effective as a locker, but it does help.

I guess maybe a good explanation of the situation you describe would be power braking. In 2X4, once the back wheels start to spin, the traction control starts putting brakes to the rears to stop them from spinning. This is what I think you would have happen. I don't think the ABS would factor in.

Am I understanding you correctly? :undecided
 

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yea.. but traction control is one of those fancy things in the newer vehicles.. lol

i gotta get a G80.. woudl make things so much better..
 

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2002 chevy trailblazer_ls
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in this situation, my point is that without ABS I guarantee I could have stopped in just a few feet. But with it, it was almost like no brakes at all. I was going faster and faster all the way down.
Would it be possible to hook up a switch to the ABS, so that when you go off-roading you can turn it off. Could that have any Damaging effects on the vehicle(not including when you lock up and crash):D
i have thought bout this myself... could be done.. simpliest way is to rig up the fuse with a switch... switch is on.. the fuse is connected and abs works.. switch is off the fuse is disconnected and abs is off...
I have a very simple control on '02 LS (w/ G80 locker w/o traction control) that disables the ABS on the rear wheel only. It is a black lever between the transmission tunnel and the front passenger seat. Pull up to lock the rear wheels and push the button to re-engage the rear wheels' ABS.
It works going up hill or down hill, but only if you are not feeling any gas. The weak link with this set up is I am not always calm enough, quick enough, and/or thinking ahead enough to use it to its maximum advantage.

I am pretty sure most Trailvoys came equiped with this from the factory. Check the owners manual and the codes on your glove box door.
 

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2007 chevy trailblazer_ls
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If you're in 4WD, some of it will transfer to at least one front wheel, though...

Mike
 
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