10/06/2026
Another good reminder about the importance of correct tyre pressures
Robert Pepper - automotive journalist
Shear strength is resistance to tearing. Sand has a poor shear strength relative to most other surfaces and this affects how we drive on it.
Think of it this way - if on bitumen you spun your tyres then you'd hurt the tyre far more than the bitumen. On sand, you'd 'hurt' the sand by digging in, and your tyre tread wouldn't be affected. That's shear strength, or lack thereof in sand.
When you have a surface with a low shear strength then you need a large contact patch to avoid surface tear. If the surface is hard, then a larger contact patch is less useful - you don't need to air your roadcar down to accelerate hard.
But what if you did air your roadcar down, you'd have more tyre in contact with the road? Yes, and then you would have less pressure per inch which may in itself reduce traction unless the tyre is very grippy and soft, such as in drag racing. Think of Blu-Tack being pressed into a rough surface, or just resting lightly on top.
Anyway, the summary is - lower tyre pressures work in sand! Other setup tips; lock centre diff if you have one, engage 4WD if part-time 4WD, and disable ESC. If unsure how to do that then use low range which sets up the electronics well for sand driving.
[ Also: you glad I didn't make this one of those oversaturated AI infographics everyone is posting now? Bring back actual graphic design! ]
