Geting through Mud....

[Jonny Boaterboy]

So to get through Mud are you better to use High or Low range? In the past I have used low locked into 2nd (Auto box) but would you be better using high locked in 1st to get faster turning wheels? I have Traction control as well does this work better with faster turning wheels?

What do you think?

[Range Rover Blues]

If they are too fast you'll burn out the brake relying on TC, though it switches off to prevent this.  With an auto I'd suggest low box then you keep engine braking.  It'l do 30 in low box anyway.

[Skibum346]

I've always been told low 3rd for mud. This helps prevent the torque spinning the wheels and breaking traction.

Course... how you manage that in an auto... is anyones guess!

Skibum

[muddyjames]

no mud is the same so my guess is what ever suits the conditions at the time.

a bit of mud greenlaning, 2nd high would do it but on a pay and break site it would be best to be in low ratio the whole way round.

[Boddle]

no mud is the same so my guess is what ever suits the conditions at the time.

 I agree, Generally low box but using higher gears  3rd and 4th are not unusaul for my TD5 defender.

[clbarclay]

I would stick to low box. Selecting 2 on the auto box limits to 1st and 2nd gear so you are still starting off in 1st, so if you are having difficulty starting of because due to a lack of traction then hi box may help. I find the torque converted much better whan a clutch on a manual for controlling torque when starting off.

I've always been told low 3rd for mud. This helps prevent the torque spinning the wheels and breaking traction.

Are saying then as wheel spinning increases traction is reduced?


The graph below is one from some of my 2nd year coursework where the tractive performance against wheel slip of a tractor on soil was measured. The X axis is wheel slip (times by 100 to give percentage) and the y axis is drawbar pull measured in kilo newtons. The green dash, blue pots and purple dash/dot lines are 3 predictions using established traction prediction equations based on wheel slip and the black crosses are expereimental measurements.

Note how at 0% wheel slip the tractor deson't generate any traction and as wheel slip increases so does the traction. Wheel slip below 20% is not obvious at a glance which is why you don't tend to notice it untill you have reach the vehicles traction limit and is sat their with its wheels spinning and not moving.
In order for a vehicle to move it must generate enough traction to ovecome resistance, typically due to rolling resistance and resistance due to gravity for off road vehciles. Therfore before a vehicle will move on soil the tyres will have to slip to some extent. As an example tractors are typically run at around 12% for maximum efficency when cultivating.

[Jonny Boaterboy]

No way Boddle! what awesome detail on the traction...... so if I understand it correctly your telling me that a certain amount of wheel spin is needed to get through..... this is where I have been going with this thread. If you go into mud at lets say 5mph ( take momentum out of the equation for now) as soon as you hit the mud you will stop. If you approach it at 15mph you are more likely to get through with the wheels spinning. The general rule of thumb is as soon as you spin the wheels you lose traction, which is what I have been trying do when encountering mud, i.e. engaging low range and locking it into  1st or 2nd thus not allowing the wheels to spin too fast.... and then getting stuck!

Then last new year when I had ventured off the track in some woodlands to camp over new year some guys came down the track in fully kitted out Disco's. They were a little worried that I would not be able to get out (my Range Rover been standard with AT's on..... what do they know!) as we were at the bottom of a track which was wet muddy and had ruts that were 3 foot deep and Cris crossing it. They turned around and made they way back up. (which took them a couple of attempts) I was surprised to see them using alot of.... grunt! Up until now I had always been very gentle off road mainly for fear of breaking half shafts. These guy used alot of speed and alot of spinning of wheels which I had thought would damage the running gear. When a couple of days later it was my turn I tried my normal approach, nice and steady and gently...... and could not get up the track! Locking it in low 2nd I floored it it and shot off up the track! it was about 200 meters to get past the worst of the track and the whole time the wheels were spinning with the traction control kicking in and out. If I had tried to creep up it I would still be there now but with a bit of wheel spin in the mud I made it. And that where this line of thought came from and so the question low or high range. In low range if you are going through mud locked in second and you blip the accelerator to blast through a bit of mud the wheel spin is only slightly increased, if hi high range and you blip it (locked in 1st) you get alot faster spin..... which seems to be what you need to get through mud?

So does that make sense!

I'm also not sure how much better MT's are over AT's as with the right amount of speed momentum and wheel spin I think I could give the MT's a run for there money.......... It's just a thought!

[Skibum346]

I've always been told low 3rd for mud. This helps prevent the torque spinning the wheels and breaking traction.

Are saying then as wheel spinning increases traction is reduced?

No mate... if they are spinning traction has already been lost... but a wheel will spin more easily in a low gear as the torque going to it is greater. Conversley, a higher gear has less torque at the wheel so less chance of breaking traction.

Obviously this has limits... even in low box it might be difficult pulling off in fifth!  ;) :lol:

Skibum

[Skibum346]

Johhny,

Tackling a hill like you describe needs a different technique to just "getting through mud". Some has to do with momentum, some with wheels momentarily getting traction and the various other gadgets & gizmos dependant upon vehicle.

Try it in a bog standard series with no centre diff lock or traction control, you'll need a different technique.

Try it in a 90 with front, centre & rear diff locks... again... different technique.

If you are on private land and damage isn't an issue, then sure... hit the loud pedal... a greenlane... tread lightly comes in and you find a way round using other lanes... or go home!

There are too many variables to get a single answer to this question. The long and the shrt of it is use different techniques as necessary and discover what works best for your set up.

As to the difference between muds & A/T... until I had some Muds... I didn't think it was great... I stand corrected!

Skibum

[Jonny Boaterboy]

Thanks Skibum, it does seem to be the case that all setups require different skills for different situations. I am beginning to understand this to the point that I have come to the conclusion that you don't actually need a 3 inch lift, winch massive wheels etc. to get every where you want to..... you just need a bit more skill than the fully kitted out Disco, or you need to read the ground a bit more than the jacked up defender. While I was off roading at the Bala 4x4 sight one of the marshals said to me that it was nice to see a standard vehicle getting round every thing that the fully kitted out vehicle were. Ok I didn't go every where they were going but the places I avoided were the places where they were winching them self's out.

I  have decided that I'm not going for the out and out offroader now, I'm just going to improve the parts that get me stuck. at the moment this is getting a removable tow hitch and waterproofing the dizzy as these are the 2 things that have resulted in me getting stuck. Even when I do get MT's (I know skibum, your right about the AT vs MT I was just trying to convince myself that I don't need to spend £500!) I won't be going for massive tyres just the biggest I can get under with no mods or altering the on road performance (Copper STT 245 75 R16) I will only be losing out on an inch or two compared to someone with massive tyres and that can be over come by a bit more ground reading or momentum. 

So thanks for that Skibum I think that kind of concludes this thread, getting through mud:

Consider the type of mud, where you are, and the set up of your vehicle, and use the technique best for your vehicle, which will be different from vehicle to vehicle

Easy!

[Skibum346]

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