I‘ve heard different things regarding tire pressure for best fuel economy. Do I do what it says on the inside of my door(35 psi) or what it says on my tires (50psi)? My tires and wheels are not stock so I am curious as to what to do. thanks
For the best answers, search on this site shorturl.im/aw6XX Go with what is inside the door, at least to start with. The max tire pressure on the side of the tire is just that, the maximum safe pressure for that tire. Your car manufacture would know what pressure works best for your car. However, this pressure is also based on the tire that came with your car when it was new. So start with the pressure listed inside your door, then watch the tread wear. If your tires are wearing in the middle decrease by a pound, if wearing on the outside then add a pound.
Not a single person got this right. Time for the professionals. To begin, there is no RECOMMENDED inflation pressure listed on the sidewall of the tire, only an informational listing of the tires maximum load carrying capacity at the tires maximum inflation pressure. That is not a recommendation. In fact if you really look at the sidewall there is a notice there to refer to the tire load and inflation tag inside the door for the recommended pressure for your vehicle - but nobody EVER looks at that bit. If you contact the tire manufacturer they will tell you the same thing. Go by what the car says. The vehicle tag will be accurate for any tire from any manufacturer so long as it is the same size as originally installed on the vehicle. Inflation pressure, contrary to popular myth frequently perpetuated around here, is determined by tire size, not brand or model. If you have changed tire sizes then different inflation pressures may be required. There is a simple way to calculate this but I would need to know your vehicles original tire size and recommended inflation pressure (or at least year/make/model) as well as the tire size you are currently using - including the load index. Its the most important part but nobody knows what it is so they always leave it out.
OMG! Where do some of these answers come from? Look, as you have already guessed the door sticker applies to the factory installed / stock tires sizes ONLY. Aftermarket performance and / or upsized tires should be inflated in accordance with the recommendations on the tire itself. Inflate to the max psi listed on the sidewall. Now a liittle experimentation is in order to determine the optimum inflation pressure in regards to ride, handling and wear. Start out at say 47 psi on a 50psi max rated tire and see how it performs over a month or so, then go from there. Edit: Well, here we go again.On my 1969 Pontiac Firebird which came equiped with E78 X 14 tires (remember those?), the recommended inflation pressure in the Owner's Manual and the door sticker is 26 psi front and rear. However, this inflation pressure just doesn't seem to work for the Goodyear Eagle F1 GS-D3 245/45ZR17 tires that are currently installed, Hmmmm, wonder why? (maybe because they require 48 psi to 51 psi to handle and ride as designed - you know. fully inflated rather than almost flat at 26 psi). Not being a tire professional, I am so confused, whatever shall I do?
