RL09

I don't understand tire pressure.

They put on my winter tires, and simply put in 245 kpa, or about 34 psi.

My tires say Max 50psi on them.

So.... How come they don't fill 40 or so in them.

Would 34 be low?

projektvertx

iTrader: (2)

Tire specs are based on manufacturer testing, not max loads the tire can take. A light bump at 50PSI would probably burst the tire...

01acls

34 PSI is high or about right in anticipation of lower temperatures to come. Spec calls for 32/30 PSI FRT/RR.

High speed driving at 112 MPH and higher calls for 36/35 PSI FRT/RR or risk of a blowout due to heat build up.

The maximum 50 PSI is for the tire technician when seating the tire bead to the rim when mounting the tire. PSI higher than 50 will risk the life and limb of the technician due to the tire possibly blowing out.

RL09

Gotcha. So I suppose I need to reduce them a bit.

Coz they got nitrogen inside and tech said they won't decrease in pressure with the cold weather?

01acls

I would leave them alone because you can expect the tire to loose around 2 PSI per year with nitrogen gas fill tires.

RL09

I live in the great white north. These are winter tires i'll be replacing in April back to all season tires.

horseshoez

iTrader: (2)

Sorry, whoever told you nitrogen won't decrease in pressure is an idiot; two points:

• Good old fashioned air is 78% nitrogen; at best, tires filled with nitrogen end up only about 92% pure.
• Nitrogen is just as susceptible to the Ideal Gas Law (PV = nRT) as any other gas, change the temperature and the pressure WILL change.