Can anyone tell me what my tyre pressure should be?

Question

I Have a nissan 200sx (s14) and have kingcross 225/40r18 's on the front and need to know what pressure they should be. And i have 225/35r18 's on the rear wheels and also need to know the correct pressure

Answer 1

All of the above answers are totally and completely wrong. I should know since I work in the tire industry.

Every size of tire will have a different load carrying capacity depending upon how much inflation pressure it carries. The original equipment size and factory recommended inflation pressure (found on the drivers side door jamb) are a starting point. You'll then need to use a Load and Inflation Table to calculate how much air your oversized tires should use. You'll probably need to visit a tire store to find one of these tables though - and hopefully someone there will understand plus sizing and how to use it. A lot of tire guys don't, which is sad.

Since I don't know what you OE tire size or inflation pressure or even the year of the car and I don't have a complete Load and Inflation Table with me I'm going to have give a random example. Lets just say for argument that your car originally had a P195/60R15 87H tire with a factory recommended pressure of 32 psi. That equals a load capacity for that tire of 1,146 pounds. A P225/40R18 83W tire at 32 psi has a capacity of only 1,025 pounds. Even at its max pressure of 35 psi you only get 1,074 pounds. Not a horrible difference, but not great. A Euro-metric sized tire (no "P" at the beginning and a higher service rating than 83) should be fine, but again, I don't have all my stuff with me.

So go see your local tire dealer and hope they have the right information and know how to use it.

Answer 2

Go by the tire, the car manufacturer has BS numbers listed on the door jamb, but all tires have different max pressures, so you have to go by what the tire manufacturer says, not the car manufacturer, they didnt make the tires....If the max is 40psi then fill to within 5 pounds under the max.... so 35psi.

Answer 3

Easy...get on your hands and knees and look real close on the sidewall...ya might need a magnafying glass...it should be marked if the tires are from a reputable manufacturer........then adjust them to your personal preference...remember an underinflated tire will cause more gas consumption

Answer 4

u can also look in the door jam if the r stock tires if there not then look on the side of the tire but the easiest place to see is in the door jam or on the door where it latches it is easier to see then on the tire goood luck

Answer 5

the correct tire pressure will be listed on the side of each tire

Answer 6

if they are the same size tires that comes from the factory,then it should be written down on the door jam.