LE Plus 17" Tire PSI?

[dieselscout80]

What PSI do you run your stock 17" tires at?

Mine were at 32psi and at the first service the dealer said they set them to 36psi.

I noticed the tires say 51psi is max, but I think that's way to high.

I'm thinking of trying 40psi.

My MPG monitor says the lifetime avg is 39 MPG for almost 14k miles.

Will a higher tire psi raise my MPG any?

 

[Scott O'Kashan]

You can't go wrong by following the recommended tire air pressures listed on the Tire Placard located on the end of one of the doors near the latch. The owners manual will list the same recommended tire air pressures.

The inflation pressures listed on the sidewall of a tire are the maximum safe recommended inflation pressures, not the recommended inflation pressures.

Over-inflating tires can cause the center of the tread to bulge out, causing premature tire wear in the center of the tire. Sometimes a mild fuel economy increase can be had with over-inflating tires, however when we consider the high cost of a new set of tires because of the tread in the center of the tire wearing out prematurely, it might not work out economically to over-inflate tires.

-- B.F. Goodrich T/A Certified Tire Specialist

 

[TigerHeli]

I disagree and think you can go wrong following the recommended tire pressure.

As we said in another thread - some tires like fairly high pressure and some don't.

I would run the tires at 32 (per the placard I think) and get a tread depth gauge and check the treads after about a month. If the outside and inside treads are lower than the center, raise the tire pressure. If the outside and inside treads are higher than the center (unlikely at 32 psi), lower it.

 

[Donabed Kopoian]

I had a set of Fuzion ZRis (worst ... tire ... ever ... thanks Firestone!) that had to be set at 42 psi or I would wear more on the outside of the tires. Sidewall was ridiculously soft.

 

[little rebel]

I have been reading another forum and im looking at what other people are saying they do to save fuel and im seing some stupid stuff being done. like turning your car off while moving, one guy said he runs 50 psi in his tires, another says use the max psi on the sidewall, THIS STUFF IS CRAZY!! Im not even going to comment on turning your car off while moving. but putting 50 psi in your tires is dangerous for you and everything around you, it seems to me that if you over inflate your tires a few pounds can get you better mileage and yes i have done this on every car ive had, but it hasen't done a thing for my mileage, i do this for comfort and handling. this is only a theory but it seems to me if you under inflate them you will get a more comfortable ride, this is what ford did in the past and look what it got them, so if you over inflate them you get less rolling resistance that's a fact but only by a few pounds but you loose some of your grip to the road, so if you put 50 psi in your tires then you should loose a lot of grip because you have even less tire on the road. does anyone remember when you rode your big wheel as a kid and could slide them wheels so easy? well its the same thing. once i bought a set of tires for a truck and as i drove home i noticed the truck was very ill handling so i stopped to check the tires and found that they had put 45 psi in them and they were only supposed to have 32 or so, i was pissed so i waited 30 minutes and changed the pressure myself, sorry to be so long but i just think it is so irresponsible that grown adults will promote this crap to others who may or may not know better. READ THE LABEL ON THE DOOR JAM AND NEVER GO MORE THAN 2-3 POUNDS EITHER WAY.

 

[jolly]

What PSI do you run your stock 17" tires at?
Mine were at 32psi and at the first service the dealer said they set them to 36psi.
I noticed the tires say 51psi is max, but I think that's way to high.
I'm thinking of trying 40psi.
My MPG monitor says the lifetime avg is 39 MPG for almost 14k miles.
Will a higher tire psi raise my MPG any?

I personally would'nt play with tire PSI (unless, as TigerHeli said, there is obvious signs of uneven wear), and would certainly never ever go to the max PSI of the tire.
The one in the owner manual or on the door edge has been determined by the professional engineers who conceived the car and choose the tires. Nobody is perfect, but I tend to trust them on this subject...
Your gas millage is already very good for 17'' tires (assuming it is 39 mpg US). That's my lifetime average with LE Eco at around 11K (39 mpg US = 46 mpg Imp).
As far as overinflating for mpg, Popular Mechanics has this test which show a marginal gain of about 0,1% vs a lot of annoyance
http://www.popularmechanics.com/cars/news/4199963

 

[Scott O'Kashan]

little rebel - You are 100% correct! :thumbsup: Thank you for sharing that. You might have saved a life.

Also, over-inflating tires makes the ride much harder and since the tire is much stiffer, it is less able to absorb road impacts because there is less, "give". The result can be a catastrophic tire failure and possibly a serious crash that causes personal injury, or worse.

An overly stiff ride from over-inflating the tires can also cause expensive wheel damage and will also wear out the MacPherson struts faster. Tires are expensive to replace, so are wheels and struts. All in the quest to save pennies on fuel costs? It just doesn't economically add up.

AMSOIL synthetic motor oils have been documented to save much more fuel than over-inflating tires. If anyone wants to save money on fuel without knocking your teeth out from over-inflated tires, private message me and I will take care of you.

-- B.F.Goodrich T/A Certified Tire Specialist

 

[TigerHeli]

Generally, I agree with Little Rebel, but ...

Turning off the engine is a hypermiling technique - there are a few cars that do this automatically (they don't shut down the engine, but they turn off fuel to the injectors). Not worth it to me to save at most 1-2 MPG. (It's generally done while coasting or braking on a highway, so moderately safe, but you never know when someone will be in your lane oncoming ahead (drunk) or similar and you need to accelerate and maneuver, and you don't want to have to worry with - shift to neutral, start engine, shift back to D, etc. at that time.

There are people on other forums running 60 psi in regular street tires - not a good idea IMHO, and I said so in the thread, but they claim they have done it for several years with no issues. Again - I don't recommend it and don't want to be driving next to them.

Underinflating the tires generally helps ride and dry handling, over-inflating makes the tire less likely to hydroplane and helps load carrying capacity - all other things being equal.

The door jamb is designed for the tires that were delivered on the car. There are some tires that will need more or less than 3 PSI difference from the door jamb - although the door jamb should be a safe number for the majority of tire designs.

 

[Scott O'Kashan]

The tire placard shows the Toyota engineer recommended tire inflation pressures for a given size and speed rating. That's it.

--B.F.Goodrich T/A Certified Tire Specialist

 

[dieselscout80]

Well I guess asking what PSI others are running is to much to ask.

At both 32 (factory recommended) and at 36 psi the tires showed even wear.

The factory recommendation is just that a recommendation. On my 97 GMC K3500 I run the sidewall max of 80 psi since I ask the truck to haul heavy loads including a Lance camper. I have obtained great mileage out of my truck tires over the course of +265,000 on that truck.

I'll just figure out what works best for my corolla.

 

[little rebel]

Well I guess asking what PSI others are running is to much to ask.

At both 32 (factory recommended) and at 36 psi the tires showed even wear.

The factory recommendation is just that a recommendation. On my 97 GMC K3500 I run the sidewall max of 80 psi since I ask the truck to haul heavy loads including a Lance camper. I have obtained great mileage out of my truck tires over the course of +265,000 on that truck.

I'll just figure out what works best for my corolla.

Sorry I couldnt give a quicker answer, my 14 corolla s which I no longer own, (I couldnt get by without a truck) I put a total of 7500 miles on it and got a total average of 38.8 mpg (with non ethanol gas). If your getting 39 on ethanol blend I wouldnt change a thing, that's great mileage. I tried ethanol blend for about 600 miles or so and my mpg took a dive to 35 mpg. my tires were set at 40 psi from the dealer so I changed it to 33 and kept it there the whole time i had it. that's where I got the best ride quality. it was a 6 speed manual and I always over the years used neutral when aproaching stops and generally using low rpm as much as possible. the tacoma that I currently have is getting about 21 mpg but thats on off road tires at 33 psi as well and im going to change them to michelin LTX M/S as soon as I can im gambling on the michelin's getting me some better mpg's but im not expecting miracles.

 

[Donabed Kopoian]

Sucks you had to say goodbye so early to the Corolla, but some people use trucks so much that two car payments isn't worth the gas savings in the off event the truck isn't required.

 

[TigerHeli]

Running 80 psi to match the sidewall max on a K3500 is acceptable. Running 60 psi on 41 psi max tires to save a few MPG is not. (Not the issue on this forum, but ...)

 

[dieselscout80]

Running 80 psi to match the sidewall max on a K3500 is acceptable. Running 60 psi on 41 psi max tires to save a few MPG is not. (Not the issue on this forum, but ...)

I completely agree it would never be safe to run tires above the max PSI stated on the sidewall.

 

[Scott O'Kashan]

It's not even a few mpg, it's a few tenths, which is not worth all the negatives of a too-stiff riding tire, to me anyway.

 

[dieselscout80]

Well after a few a couple tanks of running my tires at 38 psi our Corolla showing an average MPG of 40.2 per the display.

This is a one MPG increase, but I doubt I will increase the pressure any higher though since 38 psi seemed to be noticeable in the ride quality and road noise on rough pavement.

On smooth pavement or concrete it did not manifest any changes and the tires are still wearing even all the way across the tread surface.

I may even try going down to 37 psi.

 

[dieselscout80]

Well I took a longer road trip and I'm very happy with the MPG.

The trip was around 340 miles one way.

On the way up I made 40.75 MPG, but that included 3 days of in town commuting in some what bad traffic. I should have filled up as soon as I got there.

On the return trip I made 42.5 MPG, but I did refuel as soon as I got back.

My display AVG MPG gotr as high as 40.6 MPG on the return trip, but shortly after getting back it dropped back to 40.5 MPG.

Note I have a LE Plus NOT a Eco version.