Tire pressure

If you haven't done so ... create an account on owners.toyota.com and register your vehicle by VIN.
Also update your "Servicing Dealer".
Once that is set you can view your Service History as is known to Toyota.
In my case this also includes the Pre Delivery Inspection record.
If you see a PDI and tire pressure is off or undercarriage plugs not installed the dealer committed fraud.
See attached:

 

You know it doesn't matter what vehicle you own, the debate over optimal PSI exists for every vehicle.

I experimented a little with the Prius, when I first got it but I guess I'm boring, I ended up just inflating to Toyota's recommendation in the door jamb.
I figure that's Toyota, the builder, the manufacturers recommendation and it seemed a pretty good inflation. Good gas mileage, good ride.

With the Prius, and regenerative brakes, and aggressive traction control, I also felt I just wanted to stay at recommendation.

I do the same now with my Honda Fit.

People will take offense, but I think a lot of the inflation above the recommendation is just some part of human nature that likes to think that they can discover "better". I'm convinced whatever number Toyota or Honda printed on their door jamb, you'd get a large contingent of owners, simply NOT using that recommendation.

But in my experience? There's nothing wrong with just going with what the Owners Manual recommends, and also...I think it's a good recommendation.

 

Any opinions on tire pressure for this car? It says in the door 36 front 35 rear. I just checked for the first time since buying a month ago and the dealer had them at 51! I reduced to 40 and 39 for the moment.

 

I see the 'best' inflation pressure as a trade-off, a compromise between conflicting goals, competing factors. The car makers weight those factors according to some perceived 'standardized' customer or market. But different customers give different weights to those various elements, thus will find their own 'personal best' comprise at different pressures. So you are right, whatever the maker puts on the label, a large contingent will choose something else.

Those of us putting more personal weight on MPG, and less on ride NVH (noise, vibration, harshness), will air up. But many drivers simply don't want to put up with that extra NVH, so I see no shame whatsoever in sticking to that door jamb recommendation.

 

I don't really know.
This debate reoccurs continually. And the only thing I've learned? Is if someone thinks it's better to run their PSI 10 PSI higher than the recommendation? Nothing I say is going to convince them otherwise.

But I don't necessarily buy the defense that the manufacturer is using some standardized compromise. As the designers? As the sellers? I think they are pretty well equipped and motivated to provide the best PSI. They have to sell the vehicle, which means they want the best EPA numbers, and they want the best ride. There is no advantage I can see for them to NOT know, discover and recommend the best PSI for their own vehicles.

I especially felt with the Prius, and regenerative braking, and hybrid tuned traction control, that I wanted the recommended connection between the road, wheels and suspension.
I also felt, I was getting perfectly descent MPG and a good ride.

Maybe I'm just gettting old...but now? My answer to what is the best PSI? Is always...what does it say in your door jamb or owners manual.- I don't feign to know better. I also don't believe I can convince the experimenters or those that think they know better, that maybe it is not.

 

I must include 'marketeers', much more than simply sellers. They must appeal to buyers on many different aspects of the product.

Ford very clearly botched this on their 1990s Explorers, where for ride comfort reasons, they 'recommended' a pressure too low for safety. This was one of at least a half dozen contributing factors identified in the huge string of Ford Explorer / Firestone Tire blowouts & rollover fatalities. Firestone's manufacturing defect was by no means the only cause.

My household had an Accord and Integra pre-dating those Explorers a bit, with the same low 'comfort' inflation recommendation. Both were surprisingly susceptible to hydroplaning at that pressure, a very serious problem in Seattle's rainy climate. That pattern was cured by converting to some older style higher tire pressures. Subsequent discussions here revealed that the aviation industry already knew of this link between inflation pressure and hydroplaning, even producing a formula for their relationship.

As a result of these revelations, I have never since taken a vehicle makers 'recommended pressure' as gospel.

 

I like to keep them around 40/39 for the ride. A bit less floating feeling at highway speeds from my point of view. I keep the same pressure for winter and summer tires.

 

I like to keep my LRR tires (Toyo Nanoenergy A29) near the halfway point:

In the scales below,
the R marks the number for how much PSI for my rear tires, and
the F marks the number for how much PSI for my front tires.

LRR: ( MIN door jam says 36/35 ---RF-- 44 sidewall MAX )
F: 41
R: 40

This gives an excellent balance between low rolling resistance and even tread wear.

However, I do something different with my winter tires, given the Nokian Hakka 9's max sidewall of 51 psi:

Hakka 9: ( MIN door jam says 36/35 --------RF---- 51 sidewall MAX )
F: 46
R: 45

 

OK, it's getting cold at least in the morning here in North. I have had my tire pressure (cold) set at 38/38psi all summer long but started seeing the numbers down to 34-35psi in the morning, just from the cold ambient temperature. I adjusted the cold pressure reading to 38psi at 50F (=10C). This morning ambient temp down to low 30F (2-4C), I see this.


Then the car was parked at work for 8 hours. Ambient temp this afternoon reached 80F (27C), and I see this. This is cold tire pressure differences day and night in our region this time of year.

 

Anyone know where the tpms trigger is? I'm estimating it at 28 psi but all my gauges suck eggs so I have only a general idea what the psi is when the idiot light turns on.

I really couldn't care what anyone else runs their tires at. 38-40 all around. Like I said above, not one of my gauges agrees with any of my other gauges, so I don't put to much emphasis on what pressure the tires are running at at any given point.

 

I've read 20 to 25% off from reset baseline as a trigger point in some threads. If you have never reset the TPMS, default is 35/36 psi. That means around 26.25-28.8 psi would be when the light should come on. But I have not seen TPMS warning come on mine yet, so I don't know for sure. I will try checking it when I switch to a snow tire.

By the way, how old are your tire gauges? I have checked 5 different gauges to compare the value to each other, and result value to the external TPMS and internal OEM TPMS sensor value. The only one that did not agree with the rest was the over 10 years old tube type gauge made by Tru-Flate. All the rest purchased within the last 2 years, both digital and analog ones, were in good agreement. The manual gauge value matched external TPMS value perfectly and within 1-1.5 psi from internal TPMS sensor reading (higher than external readings). One pressure gauge I never trust is the one that is attached to the air compressor. That never reads the accurate pressure even with the pump turned off, but read much higher than actual with the pump on.

 

Like I said above, I really don't pay that close attention to them, but YES my compressor gauge is 4 or 5 lbs high too. So I fill to above 40 around 42 and usually have around 38 - depending....
I got a flat while on vacation before my 5k service. I was rescued by a local with an air tank and tire repair kit who helped me fix the tire while on the car. Coincidentally, I was just about to begrudgingly hook up the OEM tire repair kit before he arrived with the right tools for the job, thankfully.
Plenty more to this story regarding OEM repair kit, service intervals, tpms warning light, tire, wheel, tire pressure used, etc, that I'll eventually get around to posting when appropriate.

 

It seems like most who use the OEM compressor kit end up getting a new tire, probably new tpms sensor (and incurring the calibration cost for that), the labour cost for cleaning the #*#@ slime out of the rim, and on and on.

Side of the road plug repair and air up, you could be good for years.

I did two outside-only plug repairs, they both held up fine. One was an OEM tire, plugged at least 6 years back, just replace that set this spring. The other was a snow tire, maybe 5 years back, still using it.

The first instance, the OEM, was a slow leak, a finishing nail embedded in the tread. I did it indoors, while the snow tires were on the cars.

The second, the snow tire, it had a small bolt embedded, and went flat very fast, and I just noticed when we were in a parking lot. I put on the spare, drove home, and again did the repair indoors.

I use a Blackjack plug-repair kit. Besides my own two repairs I've done 3 or 4 for other family members. For airing up I use a simple floor-standing bicycle pump, very simple but it works.

 

Were they just a regular string plug? I have never done DIY tire repair yet, but that's what I bought for my PRIME. But even if I successfully repair the tire on the roadside, I may still take the tire for a professional repair later.

This is a lawyer talking, so it may be exaggerated somewhat for consumer protection and liability lawsuit against shop malpractices. But still a concern. If you know what I mean.
Unsafe Tire Repair Methods Persist Despite Strong Evidence of Dangers

 

My compressor is a hand held Ryobi 18 volt with pressure gauge. For me, having 4 other ryobi 18 v tools it was an obvious buy at $18
My next project, I hope to get around to one day is 2 Ryobi 18 volt 9 Ah batteries and a 36 volt 1000watt electric bicycle hub motor kit.

 

There are many types of tire repairs, some safer than others with some being down right criminal.
Yet they are still performed and used. Poorly retreaded tires that leave crocodiles on the hwy are close to if not by the book criminal. Yet are still preformed by so called Professionals on a regular basis.
If you ever get a chance to talk on the CB radio to a long haul trucker I'm fairly sure you'll hear a reference to the location of an obstructing crocodile on the hwy.
There are other professionals that will perform sidewall repairs on a used tire. Please look up the laws in your jurisdiction regarding those types of tire repairs.

 

Early on my Gen 3 ownership, I had a slow leak on one of my rear tires. Took to a local tire shop, they found a screw in the tread, but said was too close to the sidewall to repair. Don't remember how close, but it was not on the sidewall if you know what I mean. Ended up purchasing two new tires. I don't know if that was due to genuine safety protocol, or just simply marketing of new tires.

 

Yes they were. In both cases slightly less than an inch from edge of tread, deemed the unrepairable zone by professionals. I can see that, with an inside/outside plug, with a disc on the interior, that will start to ride up the curvature. And yeah, maybe it's more prone to water incursion.

Still, for small punctures, the plugs seem very tightly sealed. I can appreciate your reservations though.

Yeah, I'm still using one of the plug repaired tires, the snow tire. It's at 7/32", so at least one more season. It basically looks like there's a wad of chewing gum stock in there, very solid.

 

Of course, I don't see the logic why the "combination repair' in which both plug and patch are applied will prevent the air and moisture penetration into the body of the tire. I can see patch only will be inferior in that respect. But both plug only and the combination will have the same outside plug element.

 

A outside-only plug repair also flairs out on the inside, at least a loop, maybe even a bow-tie, when you think about how the needle pulls off the string on the inside.