Tire pressure - the cheapest setup change you can make

Pressure changes contact patch, carcass stability, and temperature build-up - it is the highest-leverage 2-minute setup change, and the most often neglected one.

Principles

• Lower pressure means a bigger contact patch, more mechanical grip, more sidewall flex; risks: rim strikes, pinch flats, squirm, overheating on tarmac.
• Higher pressure means stability, sidewall/rim protection, less heat on tarmac; costs grip on loose or wet ground.
• Always set pressures cold (before riding) with a quality gauge; LAISA's values are cold-set values, given exclusively in bar; psi is not used.
• On track, pressure rises 0.2-0.4 bar warm - if you measure hot, expect the difference. Wear-step or blueing patterns mean the window is wrong.

Direction by condition (mirrors the live factor table)

Condition	Direction	Why
Wet / slippery / watered (track)	-0.1 bar	Grip via contact patch, less heat is generated anyway
Cold tarmac	-0.1 bar	Compensate slower warm-up
Hot tarmac	+0.1 bar	Cap the hot-pressure rise
MX sand / mud	-0.1 / -0.15 bar	Flotation and drive on loose ground
MX hardpack	+0.05 / +0.1 bar	Carcass stability, square-edge protection
Rocky	+0.05 / +0.1 bar	Rim and pinch protection beats grip
Supermoto dirt section	-0.3 bar	Dirt at road pressures has no grip

Rear runs slightly larger deltas than front (drive wheel, more load) and heavier riders add a little pressure (+0.0025 bar/kg front, +0.005 rear above 75 kg reference).

Floor and ceiling

Never go below the tire/rim manufacturer's minimum (MX with standard tubes: beware pinch flats below ~0.8 bar without mousse; track tires have a stated minimum for carcass integrity). When in doubt, the tire manufacturer's chart for your compound beats every generic rule - including this one.

Safety framing: starting points, never guarantees - check pressures against your tire manufacturer's guidance.