Recommended tire pressure

Hi all! Another thread got me thinking more about my tire pressure. I have two questions.

1. Do you folks run the tires per recommended levels in the door jam? Mine recommends 29 psi, but I have always run 35 in my other vehicles.. idk 29 just seems too low (and potentially bad if the tires get 1 or 2 psi lower than that due to cold weather etc)

2. Have any of you noticed an difference in TPS reading compared to actual PSI? Mine had held mostly steady at 29psi on the dash. However I went to check them with my tire gauge this am and noticed that the guage was actually reading 26 psi cold, which makes me concerned that it isn't accurate.

Intrested to hear your thoughts!

 

29 felt not right to me also. Mine came with the Toyo A30 tires. 35 feels right and wear seems to agree with how I drive it. I do need to try the chalk test at some point.

Inflated to 35 cold, the dash seems to agree. I believe the rule of thumb is that 10F flucuations will change tire pressures by 1psi? So unless you are checking the dash with a gauge at the same time, you will see day to day variations.

Also when I was hooked up to TechStream, I saw that the pressures reporting to the ECU were active down to the hundredths, i.e. 31.35psi. How accurate those numbers are between each sensor and between real life is something that I haven't bothered with. Compared to our Forester that just tells us if any tire hits a threshold, I like that the Taco reports individual pressures. Having a fifth sensor for the spare would be nice.

Finally, I am considering spooning my own tires when it comes time. I've been doing my bikes for over a decade. I am wondering what, if anything, needs to be done with the sensors? Is it a replaceable or permanent battery?

 

Interesting about the tire pressure readings, thanks for that bit of info!

I bumped it up to 30 psi but I might go slightly higher. I dont think I trust the accuracy of the TPS anymore but I do think it's still a valuable tell tale while driving. Mine came with the Firestone destinations, I'm also wondering if the lower psi is due in part to the tighter suspension of the sport and/or the marginally lower profile tires compared to the other versions

 

I put 1 or 2 pounds more than recommended in colder weather to make up for what it will lose due to temps.

 

I run 35 psi. I gauged them last night. This morning they were 34, 35, 33 and 35. After driving, they were 38, 36, 35 and 35.

 

1. No, I do not have an OEM spec tire. I do use a psi based off the tire placard requirement.

2. My TPMS and pressure gauges(digital Slime) read within +/- 1 psi.

 

You're welcome!

I haven't compared door stickers, but I think I remember hearing that the ORs are the same?

I know the dealer mentioned 'bumping my pressures up a bit.' I found them at the 35psi that I had them at when I went in. Better than the 45psi that the Subaru dealer puts in the wife's tires.

 

The TPMs is accurate per my nice pressure gauge but it seems to check in increments of time. It’ll show the pressure going up or down by 1 psi if it raises slow enough, if you inflate quickly from 10 to 35 psi you’ll see that jump.

Fun fact- if a tire shop recalibrates your TPMS positions and they show as - for each tire, the psi will show up after a couple miles. No need to worry.

 

There is a rule of thumb on the street bike side that says an optimal pressure change is 10% for your normal riding. You're sort of in that range except for that last one? I believe my rears lag behind when commuting with an empty bed.

 

My TPMS readings are 3-4 lbs lower than I see with gauges at the same time. I have 3 different gauges that all read pretty similar, while TPMS consistently reads lower.

I plan on bringing this up at my 10k mile checkup. Does anyone know the expected precision for those? Being off by 10+% seems like a pretty loose tolerance.

 

The same with airing down offroad. The system reacted quickly.

The fun apart was airing up after a couple miles of pavement. 20psi felt like trash and worked a lot if heat into the tires. They dropped 5psi after fully cooling.

 

The sun was on that side.

 

Your TPMS is much more accurate than a gauge. It is a pressure transducer with no human element. Trust it.

 

from my experience I recommend 32psi all around

 

32 seems about right. I used to work at a shop and we filled most pickups up to 35 psi and cars were almost always 32. That being said there is a reason they recommend 29 on the door.. wonder if they test mpg at this inflation? In any case 32 would make me feel better and is still somewhat close to OEM recommendations, might go with that. I also dont want to have to re-air everytime I load something in the bed

 

I was running 35psi for quite some time, but the ride was harsh and the centers of the tires wore rapidly. also I think over inflation of the tires will lose contact patch with the road during slippery conditions. 32psi is a perfect combination for wear and mpgs my tires are the OEM P245/75/16

 

TPMS may be more accurate, but I think the current calibration is off, if calibrating them is a thing.
I'm finding it hard to believe that 3 gauges, from 3 different manufacturers, purchased years apart, all match, and are off by the same amount when compared to what TPMS is reporting.

 

The perfect combo would probably be what is recommended on the placard if running stock sized tires.

 

what psi do you run your tires at?

 

what size tire are u running?