Insurers cannot deny claims if tires are within the tire manufacturer's (not the auto manufacturer's) specs. This is practically unheard of, except in extreme cases where driver negligence was the real factor. Most tires are rated to 44psi or 50psi (it says right on the tire) when COLD, so that could mean 60psi hot pressure for certain climates.
Remember that tire companies, like car companies, sell their product to the stupidest and most sue-happy market in the world (Americans) so they build their products to huge safety factors.
oh, and to add... make sure you check/fill your tires at different times of the year... if it's consistently 80 degrees outside, and you lock your tire pressure in then... when it's consistently -10, your cold tire pressure will be off.
No, I meant what I said about lowering pressures, and specifically for cold weather issues when having trouble getting unstuck. When you do that, you actually increase the amount of contact of the tire to the ground/road, thus increasing the friction, hence more traction. More pressure means less tire on the surface, which means less traction. Your thinking backwards here. I wasn't talking about making the pressure so low the tire starts to cup inward, just so that it puts more tread on the ground. It seriously helps, I have done it before, and it is a known working tip. You just have to be smart about it and be sure to correct the pressures once you are going again on down the road later.
Personally I stick to what either the car maker or the tyre manufacturer specifies.
The manufacturer has done many thousands of miles testing the cars and working out the best pressures for it so why mess with it?
Also, have any of you considered the pressure that you're putting that smaller contact patch under?
I went on a roadtrip through France this summer during some fairly warm weather (35 degrees celsius) and when pulling off the motorways for a rest the tyres were VERY grippy and when I got out they were almost too hot to touch. So would you really want all that heat going through a smaller contact patch? I think not!
DTMAce your reasoning for lowering tyre pressures is wrong. Sure on ice a bit more friction will help but what about in snow and slush where you want the tyre to cut through to the road base? It'll actually make things worse. Personally I run winter tyres anyway
Tire overinflation is dangerous.... If there is a defect the increased air pressure will cause this defect to become pronounced by separating bands and plies causing a blowout at highway speed.... The maximum pressure is on there for a reason... If you overinflate and have a blowout you will hurt yourself and others..... Bad idea