Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Tire Pressure

I have a 2006 Lexus SUV. The label on the door says tire pressure should be 31. When I got new tires, the mechanic had the pressure at 35. When I asked him he said the correct pressure depended on the type of tire.

between 31 and 35 psi will be fine…how accurate do you think tire gauges really are???

The mechanic is incorrect. Use the pressure specified on the door label.

I always check and adjust my air pressure after getting new tires (I just got some Saturday) and they’re always high and always differ by a few pounds per tire.

I agree with mountainbike, but there is a missing detail in the OP’s question.

Hdstein–You failed to tell us the original tire size (listed on the same placard that lists tire pressure) and you failed to tell us the size of the new tires. If the size is the same, then the recommended pressure is the same. If the size is different (which is not that unusual since tire shops like to sell what they have in stock, rather than ordering new tires), then the mechanic could be correct. Different tire sizes may well call for different inflation pressures.

In any event, many car owners opt for slightly higher tire pressures than specified by the vehicle manufacturer. As long as you don’t mind a slightly firmer ride quality, a few more pounds of air in the tires will actually yield better tread wear, better handling, and slightly better gas mileage.

However, I do believe that there is a limit. Personally, I would not increase tire pressure more than 4 lbs over the vehicle mfr’s recommendation. Luckily, you are currently within that range.

If I am correctly informed, increasing the tire pressure does not improve handling in winter conditions. I’m sure someone will correct me if I’m wrong.

Otherwise, a small increase in tire pressure will slightly improve gas mileage and tread life, at the expense of a slightly rougher or firmer ride.

35 psi seems to be the standard tire shop inflation pressure these days. Every tire I’ve had installed or checked by a tire shop in the last several years has been inflated to 35 psi. I’ve stood there and watched them do it.

I normally keep the tires on my cars inflated slightly above the recommendation on the door label. Just a few psi. I see no harm in it, and I think there may be some minor benefits. As long as you don’t mind the slightly stiffer ride.

31 psi seems kind of low for an SUV. No wonder everyone loves the ride.

The mechanic is incorrect. The recommended pressure is the pressure recommended by the car manufacturer for that car. The pressure on the side of the tyre is MAXIMUM for that specific size, and type of tyre. It is not a recommended pressure. If the recommended pressure is greater than what is on the side of the tyre, it means you need a different tyres because the ones they are trying to sell you are not designed to handle the weight of your car.

Note if you are using a non-standard size tyre, you need to do some guessing as there is no recommended pressure.  

The difference in the two pressures you have is small enough that it should not cause a problem, but I would set it at the pressure recommended by the car manufacturer.

The manufacturer psi is right.

to hdstein. I am now 80 years old & still very interested in cars. I have a small tool that measures as fine as 1/64 of an inch. I have kept track of my tire pressures for many years & found that I must keep at least 5 lbs above what is posted on the door for tires to wear evenly across the tread . I even check my tread depth at least twice a year & record the readings in a book ,also record it on my computer. Some say more air might be a bit harder on the under-carriage of the vehicle, but I am not so sure on that.

Outstanding. I too monitor wear patterns, and I find that my fronts do a bit better with 2 extra pounds. My rears do well with the recommended pressure.

But, then, perhaps it’s my driving. We used to say “if the edges aren’t wearing out first, you’re cornering too slowly”.