I always thought you were supposed to go by the max. press. listed on the tire. But I just noticed that on the tires themselves, it says to "follow owner's manual or tire placard in vehicle." Plus, I checked a Consumer Reports article on tires and it also says to go by the owner's manual or the placard in the vehicle.
The vehicle placard says to use 30 psi, but on the tires themselves the max. press. is 44. I've been using 44 since I bought the car (a month ago), but I did notice that Hertz (who I bought it from) was running around 30.
The tires are P195/65R15, Goodyear on the front and Firestone on the rear.
What pressure should I be using? There's a big difference between 30 and 44.
Guest djwolford
44 is probably the max that you can use without exploding, Keep them at about 30-32. Keeping your tires inflated that much will cause your tires to wear out quickly and unevenly.
Thanks. I just went to both the Goodyear and Firestone Web sites and both said to follow the vehicle manufacturer's recommendations.
I've always heard that underinflation can cause tires to overheat and maybe come apart. But I guess 30 psi isn't considered too low even on a tire with a 44 max. press. rating. And I guess it makes sense that the tire manufacturer defers to the vehicle manufacturer since the tire manufacturer doesn't know the weight or other characteristics of the vehicle.
Depends on the type of driving that you do. Generally - you want to run as high a tire pressure as you can. This will reduce the amout of heat generated in the tire and improve overall fuel economy, while retaining a decent ride quality and handling.
The placard in the car should only be used as a guide - not as the tire pressure to run.
Also - be a good idea to run the same brand/type of tire all around - even though they may be similar in function, handling in an emergency situation can be remarkably different from manufacturer to manufacturer.
Personally - I run mine at 44PSI all the time. That is max cold PSI - there is no danger in blowing the tire up, unless you try to do it on purpose. You'd be suprised in how much air pressure a passenger car tire can take before failure.
Guest xcel
Hi All:
___I run my 03 Corolla LE w/ Auto’s GoodYear Integrity’s at 50 #’s. MAX pressure is also a guide. Blowout occurs somewhere around 125 - 150 #’s although there is a risk at any pressure above spec. Currently I have 65,000 miles on them so far and are just now in need of a replacement. With higher pressures comes less wear, not more. Cornering turn in will improve slightly but your braking distances will probably increase somewhat. Road harshness increases with higher pressures. Your fuel economy will improve tremendously which is why I run mine where I do. Best range and fuel economy to date to date: 751 miles at 51.8 mpg. That is in US gallons.
The dealership had my Goodyear Integrity's at 37psi. I reduced it to 30psi and the ride really improved. I might set it back up to 37psi tho, if it does decrease rolling resistance.
Doesn't it slightly overexpand the tire, decreasing contact with the road and increasing wear in the center of the tread?
G
Hello All,
Tires should always be inflated to the VEHICLE manufacturer's specified rating, unless you are doing something unusual such as towing a trailer. This information can be found on a placard in the car (glove box, door-jam, trunk lid, hood lid, etc.) or in the vehicle manual.
Running underinflated causes tires to swell at the side and can create internal friction on the inner surface that can shread tires from the inside where you cannot see the damage. It also causes a reduction in tread contact as the tire rises up on the rolling centerline so that only the inside and outside edges are in contact with the road. This condition dramatically increases the chance of overheating and blowouts.
Running over pressure results in a swell on the centerline of the tire so that only the center of the tire is in effective contact with the road. The result of this is a reduced contact patch between the tire and the road. In ideal circumstances, that patch is really only about six to eight inches long and as wide as the tire. If you overinflate, you cause the tire edges to rise and cause that small patch to get even smaller. That patch is the only thing keeping you on the road. Yes, you may get slightly better gas mileage by overinflating, but that doesn't really matter when you're replacing your prematurely worn tires or, worse, driving your car through a barricade on a rainy highway off-ramp.
Cheers,
Regular Joe
Guest xcel
Hi Regular Joe:
___Coming from the Insight forums, many run their 44 # MAX spec’ed Bridgestone RE92’s rated for ~ 30,000 miles at 50 - 60 #’s. I run 60 #’s myself w/ a loss of 3/32nd’s of tread over the last 32,000 miles. Some are still on the originals at 100,000 + miles! Those that run a std. 35 - 38 #’s are replacing them at around 30,000 miles w/ wear showing at the edges. On the Corolla’s Integrity’s, I was showing more wear on the edges after just 15,000 miles at std. pressure of 32 #’s all around. After a rotation and increased pressures, the wear has been even all the way to today’s 65,000 miles. I wish I would have known about this trick from day 1! Ride is harsher, steering response has improved, and fuel economy has improved immensely. Braking distances have probably increased slightly however. I do run the Corolla year round in and amongst Chicago’s finest highways and byways with the snow, sleet, and rain. If many were interested in the absolute best traction, they wouldn’t still be using the OEM GY’s or Firestone’s as they don’t have the traction capabilities of a Michelin Hydro-edge as just one example. With the Integrity’s, I don’t feel the loss of traction at the higher pressures although they are still pretty lousy traction capable tires overall. Especially in the snow …
___Real world experiences and real world results. Less tread wear and what tread wear is seen is even across the tire when using higher pressures in the Integrity’s.
Doesn't it slightly overexpand the tire, decreasing contact with the road and increasing wear in the center of the tread?
My dealer does that as well. Every time I come in - they always bleed down the air pressure. Even when I tell them to leave it alone.
As for tire expansion and increased wear in the center of the tire - that can happen if you over-inflate the tire - but with the advances in modern tire construction - tire deformation is not a problem like it used to be.
Still - one has to tailor the air pressure to the driving conditions at hand. If you drive mostly highway miles with little city driving - then higher tire pressures will probably be beneficial. Drive a little more city or bad roads - maybe a bit less pressure for better traction and shock loading. There is no single tire pressure setting for everyone.
But at the extremes, in most conditions:
- too much pressure = reduced contact patch/traction, susceptibility to hazards
- too little pressure = reduced fuel economy, increased wear, and increased chance of damage with higher tire temperatures.
Thanks for the great info, everyone. Very interesting.
Braking distances have probably increased slightly however. I do run the Corolla year round in and amongst Chicago’s finest highways and byways with the snow, sleet, and rain. If many were interested in the absolute best traction, they wouldn’t still be using the OEM GY’s or Firestone’s as they don’t have the traction capabilities of a Michelin Hydro-edge as just one example. With the Integrity’s, I don’t feel the loss of traction at the higher pressures although they are still pretty lousy traction capable tires overall. Especially in the snow …
___Real world experiences and real world results. Less tread wear and what tread wear is seen is even across the tire when using higher pressures in the Integrity’s.
Hey Wayne,
I don't disagree with your findings, though the uneven wear of the tires will beg the question, "Where are you measuring tread depth from?" Either way, that's not my main reason for running at vehicle spec pressures.
Like you, I once believed that running at higher pressures was the way to go. I used to run at or near the tire max pressure regardless of the vehicle requirements. The car seemed to roll easier and it seemed to steer easier, which was great because had previously driven a car with no power Assist steering. Then, I had the opportunity to spend three days completing a driver training course designed for law enforcement. This was a half classroom, half track course. I decided to bring up this topic and supported the overinflation view. After bantering back and forth about the merits of each, the instructor just took us out to the track, inflated the tires of a Ford Crown Victoria to the max tire pressure and left an identical Crown Vic with the vehicle spec pressures. I ran the "decision maker" a 45mph to 0 emergency braking course with the spec vehicle and was successful on three of three pAsses. Then I ran the overinflated vehicle and I was unsuccessful on three of three pAsses. Even if I could make the turn, I just couldn't stop before the end of the lane. After that, we took the cars over to the slalom portion of the larger course. I ran the spec car as hard as I could and was successful at 2 of 3 runs (one cone hit on third run). When I ran again on the overinflated car and I spun it off the track into a potato field. Of the two more runs, only one was successful and that was at reduced speed.
Overinflation sounds like a good thing, and for uneventful driving it may be, but it reduces the size of the contact patch between the tire and the road and that's the only thing that keeps you on it. Sadly, overinflation will let you down when you need it the most, when you're stopping hard or swerving hard at the engineered limits of the vehicle trying to save your ###### or somebody elses. I just don't think it's worth it.
Cheers,
Regular Joe
ps. I definitely agree with one thing. Toyota stock tires are crap. I would never run on something like that if I had the choice.
Hey,
It blocked out the word a.s.s. I didnt' know it this forum had a filter on it. Learn something new everyday.
Cheers,
Regular Joe
Ahh, I am beginning to actually learn :
Stock pressure is basically the lowest you can run without damaging the tire. Pros are increased traction and braking, softened ride. Cons decreased milage, increased tire wear.
Maximum tire pressure is the highest the tire can run for sustained periods without causing damage to the tire. Pros are increased milage and improved steering response, decreased treadwear. Cons emergency maneuvering is compromised, ride comfort is reduced. Probably, day to day traction and breaking are reduced, but can be adjusted for.
So it isn't a problem to run a couple pounds over stock. If you start going near the tires maximum, you should expect to lose what little traction the stock tires have.
Good summary?
Yup - good summary.
FYI - on average, for every PSI you run under-inflted - you will use up 1/3% more fuel. Some cars are more sensitive to this than others.
Guest davect
I usually run about 4 PSI over stock. That's just enough to noticeably improve steering response.
200 posts
I think running about 35 PSI is ok, IMO.
I usually have my tires at 35 psi and I think that's fine.
Max
I've been at 35 since I got the car. The tires are wearing well, no complaints there, even though they are the crappy Goodyears.
