During the winter months at the 5,000 mile maintenance the service department raised the tire pressure to 39 pounds in the front and 38 pounds in the rear. They did not give me a satisfactory answer when questioned why. What should the proper pressure be for the front and rear for a 2023 Prius XLE? Winter and Spring. Should the tire pressure reading take place first thing prior to starting the engine or when the tires are warmed up?
Look at the driver’s door jam for the proper cold pressures. After the tire is driven pressures will rise 2 or 3 psi and return to spec after the tire cools to ambient.
Tire pressures are always taken cold. Dealers often are lax in properly adjusting pressure. I always use a quality tire gauge and measure pressures after the dealer has messed with them, but only after getting home and allowing tire temps to stabilize. No reason not to use recommended pressures year round, 55 front, 33 rear.
^ Just editorial. If you're at a dealership for service, and get in promptly, what are they supposed to do? Best they can do is leave tire pressure check to the last, and maybe set it a pound high. Having your own pressure gauges and a method to air up the tires, you're able to check cold temp pressure, say first thing in the morning. I manage with a pencil style gauge (one of a collection), and a floor-standing bicycle pump.
In a place like where I live, the temperature can drop by more than a few degrees when a winter storm moves in. This causes a lot of low tire pressure alarms that weren't there the day before. When a storm moves in, I'm concentrating on digging my car out and defrosting the windshield, navigating potholes, the clumps of ice falling off other vehicles, where they've plowed the roads, where there's ice, and so many other things. The last thing I need is a dash warning that a tire is low when it doesn't have a leak, because then I've gotta find a place to pull over and do a walk around to not find a flat tire, just 4 imperceptibly low ones. Many tire shops in areas like mine (and apparently dealers like yours) compensate by giving the tires a couple more PSI in the winter, just to avoid the issue. I wouldn't go more than about 2 PSI above the normal value though.
It's speculated here, and likely true, that it takes about a 25% (aka 1/4) drop in tire pressure, from the pressure set on the TPMS system, to trigger the light. For example, if your tires are at 36 psi (4x9) cold, and the system's set to that value, it'd theoretically require a drop to 27 (3x9) psi to trigger an alert.
How regularly does the average car owner check their tire pressure? Set it back during the dog days of summer to 36psi, and forget it until the light comes on in winter, may not be the norm, but it likely enough for shops to get hassled by the ignorant. Many likely still go be how low the tire looks, and 27psi can still look full in many tires.
On my 2021 Prius Prime Limited with the nice Dunlop Enasave 01 A/S tires, I put 43 psi front/42 psi rear cold. It is OK to use a high tire pressure as long as you avoid road hazard and don't drive across bumps fast. It makes sense to use a higher pressure at winter because the pressure could drop a lot if it approaches freezing, as the humid air in the tire acts less and less like an ideal gas. Some places fill with nitrogen for that reason.
Had my second flat in six months a couple days ago. The first flat necessitated a tire replacement, which took a couple of weeks to obtain (19" tires). I've since purchased and installed an OEM spare setup, and bought a plug kit and air compressor from Walmart. All good purchases. The latest flat I was able to repair myself with the plug kit, my first such self-repair. I'm age 66 with a bad back and admittedly a bit sore from it all. Anyway, I had already scheduled a state inspection with my local dealer service which I did yesterday, asking them to do an extra safety check on my repair and mounting. Not sure how closely they looked, but said it was fine. On my way I go. While driving back I checked the driver console for TPM pressures and saw they had put 43 psi in three of tires and 45 in another. I usually put 35-36 front and 33-34 in rear. Anyway, adjusted these back down to previous levels when I got home . Debating whether I should say high something about the 43 psi they put in. I live in NC and do city driving and highway. Seem excessive to mention?
Yes, repaired off. Ballpoint pen size puncture in the middle between treads. No nail or screw there, and deflated quick enough. Do some of you ride above 40psi?
I regularly use 43 psi front and 42 psi back—much better fuel economy, much less tire wear, and much better handling. The only reason to use the Toyota-recommended pressure is if you prefer a soft ride, but it comes at the expense of much worse fuel economy, many times faster tire wear, and much worse handling.
Did you unmount the tire and do a combined patch and plug? If not, are you going to take it to a tire shop and have them do it? A plug alone is not allowed by any tire manufacturer.
It involves removing the tire from the rim to put a patch behind the puncture. It should be a better repair, but I have had repairs with the temporary plugs last years. Only had one develop slow leak then, and just replugged it.
