Sunday, April 10, 2016

Footprint, traction and getting bogged.

The modern vehicles we use to get around are designed to achieve a balance between pressure to gain resistance and low pressure to avoid compaction ( on soft surfaces )

Most of these machines are designed to be flexible in use .
Not sure you can say the same about all those people who buy 4WD's . They buy the thing  expecting it to work without thinking .
We  country folks have to wear the fears of those who know zilch about the environment . Many are plain lethal with their wide tyres even on a good road
 Paradoxically many have  a 4WD and  yet don't know how to avoid getting bogged.

Typically human beings who get bogged blame the technology  rather than their own ignorance . This error also leads to poor advice , fear and irrational comments.
-- You can avoid high compaction by lowering tyre pressures which on conventional tyres ( not so much  wide tyred bikes which have very low pressures ) rapidly  decrease ground pressure and the risk of sinking on the surface .
- you need to avoid breaking the surface of the soil by wheel spinning as the roots in the surface soil provide a reinforcing effect . ( many Australian soils have sodic subsoil horizons which have very little cohesion when wet ) They" turn to soup " as we say .
-- if you can't traverse the above soils in a 2WD it is sound advice to suggest you shouldn't even use a 4WD.

Because Lake Colac has dried out several times in the last decade and not had much water in it , the still unstable organic clays are a little more stable than they were in 2009 . They are still  like driving on jelly but the cohesion forces  while weak  are strong enough to prevent you drowning if you break through .the dried  crust on top . You can always, sit or lie down and wait for help .



At April 24, 2016 , Blogger Johnniem said...

Nearly crashed into a 4WD parked on the road the other day. Everyone had jumped out to take photos of a koala .
City folks have so little idea of real risk. They buy a 4WD and still don't know when they can get off road 'It was quite safe on the roadside for a 2WD to park .
Pull over drivers!


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