Newbie Tire Questions

96740,

Without knowing brand of tire, tread depth, wear pattern, etc.,
I would just fill it at 35 psi, and ask a car- person his opinion on the tires you
currently have. If car doesn't pull/drift to one side, you should be o.k., for now.

Enjoy the ride & mpg!


96734

 

As I recall My gen 2 had 35 as the fronts and 33 as the rears. This is ideal for comfort.
44 is the maximum you can safely put in the tire.

I found that 38f and 36r was best for me for tire life. (you always want the rears slightly more resistant than the fronts as you prefer the rear to stay behind the front of the car)

 

Different tires , you might need the TPMS reset to see the tires you have on ,, many tire stores will do this for free ,,, Toyota dealer however , bring ur credit card

 

There is nothing magical about this.

Set them at the pressure on the door plate. As Jimbo said, 35 and 33.

Then reset the the tire monitoring system. When you do that, the car is told you want the tires at 35 and 33. If the pressure drops by a few pounds in one or more tires, you will get the low pressure warning.

Looks like you are on the West Coast, you will probably not have to worry about any pressure drops that tend to occur in other more frigid climates.

 

You are WISE to ask this question. The fact is, the ONLY tires the OEM inflation applies to are those that were factory installed. I am sure to get disagreement, if not arguments on this but true it remains.

The minimum SAFE tire pressure for any "automotive" (car, pickup, semi etc) tire is 75% of the "MAX COLD" pressure embossed on the tire. Therefore, in your example of 44 PSI, that would be 33 PSI in round figures.

The TMPS sensors are part of the valve stem on each rim/wheel and they are not "forever" parts, it seems like one of more is giving trouble and that is often due to a dead battery, which I think requires a new TPMS sensor on the affected rim/wheel.

 

I assume by "tires state 44 psi max" you mean what's embossed on the tire's side wall. This is the tire manufacturer's statement regarding the recommended maximum pressure for the tire, under maximum load. It by no means supersedes the values given by the car manufacturer.

If you've got a tpms light chances are one or more of your tires are low, by quite a bit, below the pressure value(s) in the door jamb decal. Have you checked the pressures?

This is a 2007 Prius?

 

Wait, you have a low tire light on and you haven't checked the air pressure?

The sidewall max pressure is half the bursting pressure, 40-38 is a good place, great traction, not to bad a ride, tires tend to lose a pound a month, so regulate.

 

If I get a tire pressure warning light, I check the pressure with tire gage ASAP. Driving with a low pressure is dangerous.
In my experience, tire light does NOT come on if your tire pressure is higher than recommended or higher than pre-set normal value.

Alex

 

A regular Prius uses 185/65R15. PSI of 35 front, 33 rear. This is printed on the door placard.
A Touring Prius uses 196/55R16. Same PSI as a regular Prius above.

Most here, seem to go a little higher than the door placard, but maintain the 2 PSI difference. 40/38, 38/36, seem to be popular inflation pressures.

The low tire light comes on if there is an issue with the TPMS components, or the system sees a 25% difference from the last reset learning. When you properly perform a reset, the TPMS learns the pressures of each wheel at this reset time. It is important to perform a reset when you adjust air in any tire, so TPMS learns the new air pressuress; minimum four times a year due to the seasons. When a 25% difference in pressure (realistically a loss), is detected in any wheel, the warning light triggers. Pull over QUICKLY! Check each tire to see which one is loosing air, causing the TPMS to trigger. A screw/nail will be a likely culprit. Pulling over quickly is for safery and can mean the difference between a repairable tire or non-repairable tire, assuimng a puncture occured in the tread, and not the sidewall.

Before TPMS, I unknowingly picked-up a nail that bleed out slowly. I only realized something was wrong because the rear of the car was acting wierd. Pulled over and realized a rear tire was completely flat, and now destroyed. Had TPMS been around then, I would have been notified early enough, pulled over quickly, saving that rear tire.

You should read this since you lack tire knowledge, for now.
How To Check Your Car's Tire Pressure and Inflate Tires | Edmunds.com

 

Not to be argumentative, but 100% false there.

If the OEM tires were "standard load" 35 PSI "P-metric" tires on your small pickup and you installed better (for your purposes) 51 PSI "extra load" tires as replacements, it would be COMPLETELY UNSAFE to inflate them to the door sticker of 28F and 30R PSI, as the MINIMUM safe pressure for a 51 PSI tire is 38 PSI cold.

This is due not because of any defect in the tire design, but the amount of SIDEWALL FLEX the tire is designed to accept under normal loads. you can make the argument that the "XL" tire will not be loaded as much - relatively and that is true, but the capacity difference is only ~100 to 200 lbs/tire between standard and XL tires in typical P-metric (passenger) sizes. This does not hold true for "LT" or "Trailer" tires, there is a MUCH larger load gain with XL with these.

Automotive OEMs set suggested inflation pressure for one or two PRIMARY criteria ONLY:
1) Ride Comfort
2) Road noise (drive-by noise testing)

Sure, they ensure that the vehicle is "safe" to drive at those pressures - stability, steering and braking all meet FMVSS requirements, but tire pressures are not set BECAUSE of ANY of those three criteria.

Doubt me? Just ask Firestone! Ford set the suggested inflation pressures BELOW the minimum set by Firestone on the Explorers; they flipped when tires blew out from overheating and people died and were injured. Had Ford stuck to the Tire Industry "rule" of not less than 75% of the "COLD MAX" pressure, that would not have happened.

Obviously you cannot PREVENT all tire blow-outs, because that relies on the operator/owner to actually check tire pressure and they simply don't.

 

googling, I do not find any of your assertions in any google search. Both Firestone and Car Talk say to go with the car manufacturer's recommendation. The only in depth discussion of minimum tire pressure was for racing bicycle tires.

Tire Pressure | Firestone Complete Auto Care
Service Your Car | Car Talk
Technical FAQ: Minimum tire pressure and more | VeloNews.com

Do I think Manufacturers are never wrong? No. Do I wait any website you can find with the claim that 35 is unsafe, sure. Could I find them? No.

 

The WEB is not the repository for all facts known to humanity.

What you really needed to find was the TIRE manufacturer's "Load-Inflation Table" and they are both Tire BRAND and Tire MODEL specific.

Good luck finding one, they are commonly available for LT and HD tires, but VERY rarely available (although every tire OEM produces them) for passenger tires. My tire guy (Michelin/Bridgestone DEALER) was told in a training course this is because they contradict the Vehicle OEMs suggestions and while I cannot testify to that being factual, Ford's battle with Firestone leads more credence to it than not.

Edit: I stated in my first post on this topic, I would get arguments

 

So you can't in fact document any of your claims? I did not and do not wish to argue with you, I wish to see your facts.

Hard cover, paperback, web, periodicals,, I am not afraid to search in libraries, or online, I have Amazon prime if it is unavailable in libraries.

Title, and Author is fine
Title and year and month for periodicals.
URLs are fine.

 

It's not? In that case millennials are screwed lol.


iPad ?

 

ROFLMAO!!!!!

Sooooo TRUE!!!!!

 

Toyota would disagree with you.
My 2017 Prius Two tires say 44 psi maximum. Toyota specifies 36 psi from & 35 psi rear for those exact tires.

 

If someone weighs in, says "you know what you'll never hear/learn/glean from the Internet", then proceeds to explain it...

 

Um, apparently they DO NOT disagree, at some level.

44*0.75 = 33 PSI would be "minimum safe"

In any event, I have two words regarding OEMs and minimum safe tire pressure....FORD & FIRESTONE.

 

Sorry about that.
For some reason, my mind read that as maximum not minimum.