225/40/18 PSI max

[sosmooth]

Hello, does anyone know the max psi for 225/40/18 size tires? They are by Nankang. I noticed my TPSM coming on and off. The pressure in each tire was at 30. I noticed that 30 is the psi for size 16 tires (stated on manufactured sticker near driver door). I would think that since they are bigger tires the psi would be different. Since the light was on, I decided to put air in all tires up to 35, then TPMS light went out. Whats the max psi for these size tires?

[gdanaher]

The maximum tire pressure is required to be listed on the side of any tire. Get out there on yur knees and start reading the sidewall.

[workerant]

Pump up you tires to 33psi and you should be good.

Most car tires I think max at 40psi. Like gdanaher said, should be written on the tire.

[darksparkz]

Yeah, they usually do go up to 40 or 44 psi for a max. For the 40 profile, I'd actually put the psi at around 37-39 psi, it actually might make the TPMS go off, but that's what happens for aftermarket tires and wheels.

[workerant]

Originally Posted by darksparkz

Yeah, they usually do go up to 40 or 44 psi for a max. For the 40 profile, I'd actually put the psi at around 37-39 psi, it actually might make the TPMS go off, but that's what happens for aftermarket tires and wheels.

Why not put in 60psi and lets see what else go off.

Max mean you are not suppose to exceed that. When your car sits, the PSI for most tires should be around 32psi. This is a tiny bit low for the tire but when you are driving the PSI increase and on a hot day it increase much much more. But ideally even with the increase pressure due to heat, it still shouldn't exceed the max.

My tire was measured at 36psi and after driving on a hot day it jumped up to 46psi. It wasn't good so I decreased it. Anyway, I will replace those tires soon.

Any low or high pressure will create an uneven wear on the tire. Some put in high psi to save gas but with 4 tires priced at $700+, it will take a lot of saving to equal the amount it takes to replacement of those tires.

[darksparkz]

"most tires" are OEM tires, so you should follow the door sticker recommendations only if you have the stock tires and wheels on.

As far as the stiffer and shorter sidewall due to his 40 profile tires, the structure of the tire bears its weight on the sidewall more, so a higher tire pressure is required to be able to help the sidewall withstand a bit of the weight of the car.

[workerant]

Originally Posted by darksparkz

"most tires" are OEM tires, so you should follow the door sticker recommendations only if you have the stock tires and wheels on.

As far as the stiffer and shorter sidewall due to his 40 profile tires, the structure of the tire bears its weight on the sidewall more, so a higher tire pressure is required to be able to help the sidewall withstand a bit of the weight of the car.

No, if the pressure is too high than the tire will puff up more. So the contact surface suppose to be flat, it's now curve out causing the middle to rub more and wear more. When the middle go thin, than you need new tire.

When tire pressure is low (low psi), than the side wall will put more pressure on the tire causing the outside to wear out faster. And when the outside treads getting thin, new tire just the same.

The recommended pressure should be around 32psi. This is more likely to have the contact surface more flat and so both the inside and outside treads will wear evenly. This last the longest and of cause eventually will wear and new tire is needed.