What tyre pressure should one use when negotiating mud?  This has been a long standing debate with every school of thought standing their ground.

There are two main theories:

 a) very firm tyres (above regular pressure).  The thinking is that will cut through the sloppy stuff on top to get to the bottom where there is more grip to drive your way forward. It is also believed that deflated tyres close the tread pattern that prevents the cleaning action – hence the firmer pressure.  Further, firm tyres give you more ground clearance that prevent your differentials from dragging through the mud that would cause more resistance and thus hurdle progress.

b) deflated tyres (as for sand) The thinking here is that it gives you a larger footprint to give you more grip and floatation over the slippery surface.  Even with less ground clearance than firm tyres, clearance would not mean much without grip.

There is logic in each of the above scenarios, but my experience has tough me that the latter still works better – especially if you are riding on all terrain tyres.  Deflated tyres combined with an aggressive tread pattern that mud terrain tyres like Goodyear Wrangler MTR provide has taken me through many mud ruts at idle speed where another with General Super All Grip (lloks like tractor tyre) at 3 BAR slid all over the place and picked up wheel spin regularly.  The most important element in the mud driving equation is the type of tyre – all terrain and road bias tyres are great for sand, but useless for mud.  The tread pattern clogs up and leaves them looking like slicks that lack grip and directional stability.