tea elle

I talked to a mechanic at the 76 station at Bundy and San Vicente and he emphatically warned me about running the pilots at 32psi. He says he's done several thousand alignments in his career and he knows a lot about tires. He says running the Pilots at such low psi will wear out the outside portion of the tire long before their time, and the performance of the pilots that come stock on our cars will be greatly enhanced by running at the higher psi.

He invited anyone on this board to contact him if they think they know more about tires. His name is Edgar, and he seemed to really know his sh!t. I've met a lot of mechanics over the years and this guy is intelligent, articulate and passionate about his work. He also works in one of the most prominent, wealthy and demanding neighborhoods on the planet! I don't think he'd last in Brentwood if he weren't good at what he does.

It's interesting to me that I have never read one single post on this board that recommended 40-44 psi. Everyone is always saying to lower it to 32 psi to improve the ride feel. Nobody talks about how that will effect the grip of the pilots, or the tire roll of them.

Would love to hear your comments. Thanks A lot.

nickchop

I have my tires at 32 psi, but they look flat. I haven't changed because this is what the manual and Acura has said to keep them at. On any other car I have owned, I would have put air in them. I'll try at 40 for a few days and check the ride out.

asiankidd

i think we should contact the tire company and ask them im sure then done more r&d for their tire than edgar....i hope edgar is right cus imma go try it right now

Bitium

I don't know about the factory tires. But my 225/40 18" I always keep it between 38-40psi. Any mechanic will inflate the tires to 40psi.

Edward'TLS

Inflating tires to 40psi would make your ride bumppy as hell. Although the response (turn-in feel) is better, the car will be very slippery in the wet.

R Man

Absolutely. I drove almost 1,500 miles at 40 psi before lowering it to 32. The difference is amazing. I'll keep an eye on the tread wear, rotate the tires regularly, and get new ones when the time comes, but I'm not going to shake, rattle and roll at 40 psi.

tea elle

"bumpy as hell" is overstating it. I drove the car last night at 42pi and it felt firmer/bumpier, but the handling was improved and the grip seemed better. If Edgar is right, the tires will last longer and wear more evenly and perform as intended.

coffeefingers

Dude,

Why am I thinking Ford Explorer right now?

NSXNEXT

iTrader: (2)

Here's a great way to tell how much air to put in your tires. Works for all cars and all tires

==============================================
There is a trick you can do to determine precisely how much pressure to keep in your tires for your particular vehicle. It will give you the best tradeoff possible between mileage, tire life, and comfort. Make sure you use an accurate tire guage so that once you learn this pressure you know it is correct.

With a cold vehicle and cold tires, air them up way over pressure. 40 psi would certainly be there. Take a chalk and mark a chalk line sideways across the tread of a front and rear tire. Drive your vehicle several yards (30-60 or so should do it). Now look at the chalk marks.

You should see the inside of the chalk marks worn off but the outsides should still be showing. In other words, the bowed out overinflated tire was wearing the middle of the tread and not touching the outside of the tread.

Release a couple of pounds of pressure from the tires and repeat the experiment. Continue until the complete chalk marks wear evenly. (You might want to lose another pound to make sure the entire tire is bearing down across the tread once the entire chalk mark disappears at the same time). You have now determined the tire pressure at which you are keeping the entire tread on the road.

Under this pressure you are wasting available fuel economy, generating excess heat, and prematurely wearing the tread. Over this pressure you will get better mileage at the cost of comfort and decreased tread life. Keeping at this pressure will wear the tire evenly and thus extend its life to its greatest extent and offer the best compromise possible between gas mileage, comfort, and safety (you'll have your whole tread on the road). The pressures may be a couple of pounds different between front and back for your particular vehicle application.

TL4Mo

Talked to Michelin and they suggested to stick with what is on the Acura manual. Only different suggestion was to always check tires when they are cold (when car hasn't been driven for about 4 hours). Other than that, Michelin's stand is to check the tread wear and as long as it's not outside of 1/32nd change of wear from tire to tire.

Also, Michelin said to check the pressure at least once a month, aside from visually checking the tires.

TL4Mo

Mr Hyde

Even with Pirelli P-zeros on my last car I kept the PSI at 35.
40 PSI was simply too harsh for me and while the response felt only a tiny bit better on smooth roads, on imperfect roads especially on turns the ride felt skittish and unsafe to me. Also my tires wore out symmetrically, not ahint of more wear on the edges which would happen on an underinflated tire.

ucla107

=*(

I just got a flat last night .... read my post @ http://www.acura-tl.com/forum/showth...threadid=20556

see.... I've had my tires at around 40psi (when warm) ever since i have the car, but then i went and got an oil change a couple weeks ago... so they probably changed the pressure back to 32psi (?? i haven't checked)...... i wonder if that has to do with me getting a flat?? uughhh

cuz in my old accord i always put 40 psi in those 18" tires... the maximum is raterd at 44psi... and the tire place says that i should always put 4-5psi lower than the maximum rated psi (for performance tires.....)

according to the Michelin website.... heres the specs for our tires (in PDF):

http://www.michelin-us.com/us/eng/ti..._pilotmxm4.pdf

it says the maximum load @35psi is 1433lb ... well our car is 3558lb/3574lb(with navi) so i technically i35psi is well enough to handle the car's weight and 5 pssangers and luggages.... but it says for speed over 124mph, increase the psi by 1.5 ... well i'm not sure how many of u guys out there drive that fast, but i think by over inflating it a little it wouldn't really hurt... sure the ride is a LITTLE bumpier.. but you get more life outta your tires... juts my $.02

yee

coffeefingers - dude...don't worry about having tire's like the Explorer...I had them!
tires are designed to much higher pressure than that...
what happed with Firestone is that their worker got pissed and started using old material to make the tire for a certain period of time. These rubber do not stick too well and will seperate in high heat.
As for the New Explorer, it's just dumba$$ Ford used the old plateform in the assembly line which rubs the inside of the tire.

thephantom

Bottomline, 40 or 32 or 35?

vandy786

That's right, someone please sum it all up. What should the tire pressure be on a TL-S with no mods (pure stock and no added weight)?

tea elle

DITTO! What should the pressure be with no mods. I'm thinking 40 PSI, although as much as I love cars, and have driven dozens of different ones over the years, I'M NO MECHANIC!

I drove about 200 miles today on wide open freeways near Lake Elsinore and on I-5 with my tires at about 42 PSI and the car felt wonderful. I want to keep the pressure where it is now because the car is cornering much better than it was at 32 PSI, and I think the bumpiness of the ride is no biggie, but I want to be sure I'm doing the right thing.

So which is it all you mechanical experts?? 32, 35, 40, 42?.....what PSI is the best for performance, ride, longevity and still safe.

thephantom

OK, I started this and I shall end this.

I have bone stock as well and I upped mine today from 30 to 35 and you know what, I love it. The ride is awesome. I don't peel out as much and the cornering has improved. I may try this for a few more days and up it again to 40, just to compare.

For those of you who are still running at 30, UP IT ALREADY!!

EricL

I looked at a CLS member's car with a good deal of wear on the stock MXM4s -- he was running 32 PSI and the wear looked perfect.

Are you talking about Michelin Pilot Sports (as in the expensive $240 each tires) ??

The reason I ask is as follows:

I am running 235/45ZR17-97W* Toyo Proxies on 17x8" +48 offset wheels (forget the wheels for now). I am running 40 psi (the tire takes a max of 50 psi -- XL rated).

I have perfect wear with this "different" tire. One of the other members on the CLS forum running the same setup only ran 32 lbs, then 35 on the Toyos and they showed the worst under pressure that I've seen in a very long time. The inner area was great and both outside edges where gone.


IF YOU HAVE THE STOCK tires, you can bump the pressure up a bit to 35 if the conditions merit (you have a lot of weight in the car) or if you are going to run at high speeds. The tires are XL rated...

If you have the NON-OEM Michelin tires – check with the TireRack, Michelin, and/or one of the better Discount tire dealers – that would be a different issue, and they may want higher pressure (don’t know)…

Xorg

This is a silly thread - when it comes to tire pressure the ONE and ONLY correct pressure to use is the one listed on the door jab or in the glove compartment.

Running a car tire at 40psi when the spec says 32psi is inane, and will do nothing but give you a harsh ride and car that doesn't grip corners like its supposed to.

Try 32psi, where its supposed to be.

EricL

For 90% of the people, I would agree... However, there are always exceptions to the rule. Although, the OEMs that I saw running at 32 looked like they had perfect wear and they were almost down to the wear markers.

As a note, the doorjamb DOES NOT apply to "different" tires -- so be careful if you ever go to a different tire. I've actually called Acura Care and the engineers at Toyo (for my tires)...

daverman

I've always wondered if there was a way to determine the optimal tire pressure for any particular tire, be it to maximize tread life, comfort or grip...

Davidas

After reading all these posts, I think the ideal PSI is 35-36 PSI.

It is a little bit more than the recommended PSI (32) and it gives a more solid and stable ride without sacrificing the comfort.

35 PSI.

tlsshopper

I don't know about your TLSs, but my TL-S stock tires (Pilot HX MXM4) are stamped 41psi maximum pressure for a max load of 1433lbs. 40-45psi would be outside that range, however ~35psi seems like it would probably be OK.

yee

when I took my car to the dealer (Acura of Pleasanton) for routine service...they recalibrated my tires to 34 psi each.

AKRY

Now you guys mentioned it.... when I was at our Vancouver Meet weeks ago, Kuan pointed out that my tires are wearing out more on the outside... and especially noticeable on the front tires...

Manaul said 32psi, but I have been running 33-35psi all around since day one......

Hm....any ideas??

Andy Kuo

EricL

The MXM4s are XL tires and the 1433 lbs load is available at 35psi. The XL rating and P designation (in front -- see link below) give the tire additional load "reserve" at the max pressure of 41 PSI. (Tire rack has a note about the SL vs. XL if you dig around...)

Michelin Tech page for the MXM4 -- P215/50R17 XL (93V)
(There are some notes about pressure vs. speed -- if and only if the manufacturer [ACURA] doesn't make specific recommendations...)


http://www.michelin-us.com/us/eng/ti..._pilotmxm4.pdf

(You will need a pdf reader...)


http://www.tirerack.com/tires/tirete...y.html#maxload


(In case anyone is confused, look and see that the max load for this "P-metric" tire is given at 35PSI -- not the max pressure!!!)

(For interest sake, the reason I can run the Toyos at 40 PSI is they are XL rated tires with a max pressure of 50 PSI.)

Please be careful -- it is just info. Not any recommendation of what pressure to use with your stock tires...

EricL

Just suggestions and some questions...

1. If you drove like a mad-man around turns, the outside of the tire would tend to wear a bit more. (Inflation could be related...)

2. Have you had the dealer or an good alignment/tire shop check the tires out.

3. (Minor suggestion) -- Are you rotating your tires -- This will help, not cure your problem.

I've seen toe-in (alignment problems) cause terrible wear on the inside of the front tires.

If you have lowering springs with radical negative camber, you would see the wear on the inside of the tires (if not corrected for).

Tire problem/help excerpt and link:

"Shoulder wear, which can be caused by under-inflation or hard cornering. Many shredded rubber tires seen along highways are the result of either under inflated tires, running too long and too hot, or from severe misalignment."

http://www.autoshop-online.com/cchtml/tire.wr.prob.html

EricL

Outside of calling and triple checking for info, I'm not sure...

I have a dumbo method... Once the tires have about 1000 miles on them (or a bit more), I will take a penny and use it like a depth gauge (I've have one too). The idea is just to take a "common" object that you can stick in the groove of the center of the tire and compare the depth at the outside(s); if the difference shows the inner part of the tire wearing MORE than the outside, its time to drop some air pressure. If the car is aligned and the opposite is true, bump the pressure up (within reason). If you have calipers handy, most have a depth gauge that can be used...

THE ROCK

maybe i don't know enough about cars or whatever, but when I got my TL, it was at 32psi. They looked just too flat to me, so a few days later i inflated it to between 39-40 psi (they still look flat, but i didn't want to really over do it). I noticed no fuel economy improvement whatsoever and not much in terms of a harsh ride. It just all felt the same! I've had them up at 39psi-40psi for about 1800 miles until the first service of the car and now they brought it back down to 32psi. I've driven it for about 1000 miles since, and noticed absolutely no diff in fuel economy (which still sucks bad).

daverman

The fuel economy difference is probably overshadowed by your driving habits. I can't imagine that you didn't notice the ride difference though! I have a Type S and I can definitely tell the difference in ride when the dealer pumped my tires up to 36 PSI during my last oil change.

By the way, you can't tell by looking if a tire is too flat! Use a tire pressure gauge to be sure.

Indyjenks

I agree...35 is where I run mine. But remember...SET YOUR TIRE PRESSURE COLD! When the tires heat up (as in driving for a period of time), you pressure increases by 5-10% depending upon type and design of the tire. Ive had mine set at 35 since I got the car and they are wearing fine. It has reduced the tire "squall" when doing moderate cornering and the ride is fine. The manufacturers recommended pressure is always a compromise between performance/comfort/wear and mileage. You can fiddle with pressure to a certain degree to increase 1 or 2 of the attributes but usually at the expense of the others.

Edward'TLS

I have used XGT-V, S-01, and SP-8000 tires on my previous car, and I particularly enjoy "throwing" my car around corners. All the tires showed excessive outside wear, with the rear two tires being less severe than the front twos.

Road Rage

32 psi for me.

Mfrs. pick these very carefully on a basis of ride, handling, fuel economy, and one thing no one has mentioned - shock load immunity. Too high a pressure can put both the tire at much higher risk for damage from impact as there is less give to the tire carcass.

And a high pressure may help turn in, but actually reduce cornering roadability by increasing susceptibility to mid-turn ruts and bumps.

I say the orginal "expert tire guy" is typical of chat room quotations - untutored hokum.

lonny

I am going to put mine at 36 lbs and see what happens. I don't care if I wear out the tires too soon because these tires suck anyhow.

thephantom

You have a good point there, the tires do suck. But, like I had posted earlier, after I inflated them to around 35, I actually don't mind them as much. I took the same off ramp that I have taken before I jacked up the pressure at around 55-60 today and I noticed a HUGE difference... much better!

tea elle

I've read your comment three times and I'm not sure what you mean. Are you saying its better with 35 or 55? 55? What does that mean? You had your tires at 55? Are you kidding? Are you sure?

Mr Hyde

Im sure he meant 35psi for the tires and that he took the corner at 55-60MPH

thephantom

My Hyde corrected me. thank you. Sorry for the lousy post, was in a hurry. I took the corner at 55-60 MPH with the tires set at 35psi.

tea elle

Don't mention it phantom...that Mr. Hyde's a smart guy.

tlsshopper

[QUOTE]Originally posted by EricL
[B]

The MXM4s are XL tires and the 1433 lbs load is available at 35psi. The XL rating and P designation (in front -- see link below) give the tire additional load "reserve" at the max pressure of 41 PSI.

Michelin Tech page for the MXM4 -- P215/50R17 XL (93V):

http://www.michelin-us.com/us/eng/ti..._pilotmxm4.pdf
_________________________________________________

Thanks EricL for the official word from Michelin on their recommended tire pressure of 35psi (refer to url above)! Based on other postings here, seems like most of us are also comfortable with 35psi instead of Acura's recommended 32psi.

Note: Went to a Jiffy Lube yesterday for a 5W-20 oil/filter change and they wanted to put 40psi in these tires; not sure where they get their specs.