Driving an under inflated tire on the highway does not pump it up to the proper pressure. The heat builds up in the sidewalls because they are flexing so much. Enough heat to separate the tread from the carcass (see: Firestone)

Tire manufacturers know that pressure increases with driving. That's why they set the COLD tire pressure maximum on the sidewall. This takes into account any increase in temperature and pressure up to the maximum speed rating. Assuming the tires are within their load range. And they under-rate things slightly so they don't get sued when people blow their tires up.

There is the under-inflated range where tires fail, which is kind of scary close to most manufacturer recommended pressures (for comfort), then a very large range of pressures where the tire is fine. It's not until you get to extremely high pressures and/or large impacts where the tire could explode.

 

So, Try the lower tire pressure again to verify that you didn't improve your driving habits.

 

Hypermilers usually suggest no more than 10% overinflation (110% of max sidewall pressure) to start with.

 

The competitive ones use 50 to 60 psig. SS racers and autocrossers routinely inflate to 45 psig cold and at the end of a race the measured psi can exceed 55 psig. Floppy sidewalls on a race trace do not inspire confidence.
And Firestone's underinflation problems were the result of overloading. You pack an SUV with 2000 lb of stuff and don't add pressure you're asking for a blowout. The load limits on tires are real.

 

roads in nyc are to bumpy for higher psi I replaced like 4 tires due to bubbles caused by potholes I cant afford it lol

 

higher PSI will hurt your ball joints and your butt! i use 31psi for smooth driving

 

OP in his first post noted he puts "...Oil 10W30 (1/2 quart low on purpose)". What is the reason to put 1/2 less quarts?
Pardon me if this was answered in the thread, but its a very long thread.... Thanks

 

Less windage. Which means less parasitic drag loss from the crack slapping through oil in the pan.

 

thanks, Is there any risk at all putting in a half quart less?

 

No, you are still running plenty of oil, there's just less tolerance to drop below the recommended minimum level if your engine consumes or leaks oil. Just check the dipstick more often.

 

Interesting read OP, I never knew that people actually did this! Guess you learn something new every day.

Personally, I'd never run a tyre any higher than I felt comfortable with as traction is far more important to me than fuel economy. That and I live in an earthquake damaged city and the average open road here involves many hairpin turns, not great for higher PSI!

My only experience in experimenting with tyre pressure's comes from the race track with motorbikes, we "read" a tyre after a race and adjust the pressure depending on the wear shown and feeling you got from the bike, if it's sliding a lot then the pressure could be too high or too low.


Apologies if this has already been asked but did your tyres get as much life as if you had ran them at the recommended PSI? If not then it would be interesting to calculate the fuel savings cost vs the early replacement cost of the tyres. Considering the cheap fuel prices in the US I'd imagine it would be pretty close.

 

I usually split the difference at 38psi and have no real complaints about ride or handling. If anything overinflation will cause the center of the tread to wear faster than the outer sections, which isn't too big of a deal I think.

 

There are a lot of people - myself included -who have run tires their entire useful lives with high inflation pressures and have not seen uneven tread wear. Modern tire construction pretty much put this old saw to bed a long time ago. As long as you stay within in the max pressure molded into the sidewall, you should not see unusual wear patterns due to high pressure.

 

Same here. Been doing it for years and never had a problem.

 

I also run my tires close to sidewall max and haven't had uneven wear so far. No blow-outs, no bulges, no center wear, only better handling & fuel efficiency.

The stock Dunlop all season tires lasted me until 61,000 km (38,000 miles), and 3 of them still had plenty of thread. I decided to change them all because winter was approaching and 1 of them was at the marker bars on the outer thread. Likely the 1st owner of the car rode it at low pressure for a while.
Since tires for the Fit are so cheap, it was worth while changing all 4 at once and getting winter & all-season sets. I keep the winter ones close to max sidewall pressure pumped on a milder day, so that when it's really cold they can drop 10-15% lower or whatever. No issues with traction.

I convinced my dad to try it on his '08 Camry with low profile 18" rims and he complained of premature center wear (almost bald) with lots of thread left on the sides. He had some 2 year old Michelin all seasons that he kept at 40 to 42 psi.
I didn't believe it until I saw them. If I find the photo, I will post it later.

Would low profile wide tires wear in the center from running close to max pressure?

 

I inflate my tires to the recommendation in the drivers door, which is the MANUFACTURER of the vehicles recommendation...FOR the vehicle. NOT the MAX the tire manufacturer sets for the tire itself.

To me the tire recommendation is like a extension ladder. The MAX for the tire is like a extension ladder that has a sticker that says it can be extended to a MAX of 20 ft.

If you only need to go 12 ft high, do you extend the ladder to 20 ft? No. Because it's not needed or even safe for the situation. You don't do it just because the ladder say's it can do it.

I feel the same about Tire Inflation. The manufacturer of the vehicle, familiar with the design of the vehicle offers a recommendation FOR the vehicle. That' the PSI I go with.

The Tire sidewall...is just like the sticker on the extension ladder. It's the MAX the tire manufacturer says the tire can be inflated. But it's NOT a recommendation for vehicle you are driving.

 

yep, plus cars drive like crap anyways at those extreme psi’s.

i just use 35-37psi on the Fit.

 

 

Manufacturer recommended pressures take more than just one thing into account. They are safe but not necessarily ideal for all needs. Driving on sand? Better air down! Want lower rolling resistance on paved roads? Raise the pressure! Want to optimize handling? Somewhere in between. And so on.

 

Sure, you can look to very specific situation where arguably changing PSI has benefit.
But that's not what we are talking about here. We are talking about daily driving, in most common situations.
And that is where a daily driving recommendation comes in.
Most of us don't have time or the predictive possibility of forecasting exactly what conditions we might be encountering. And I think most of us don't want to be adjusting our PSI on that reactive of a basis.
It's hard enough to get most people to even check their PSI, let alone trust most people are going to make the right decision about their PSI given a whole lot of changing speculative driving environments.
Therefore, if you open the door and look in the door well...you'll see a PSI recommendation the manufacturer recommends. And...that's good enough for me.
If I find myself with miles to go in a desert or a beach, or trying to cross the Arctic Highway? I'll revisit the PSI debate.