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TIA for any responce on this matter. I looked through all the messege boards and wasn't quite sure where to post this question.
The Sandman :-)
The Sandman :-)
Regarding usage, according to my Owner's Manual (which pretty much lines up with every Owner's Manual I've ever had) you should use it wherever and whenever needed. Specifically it says:
Vehicles with manual transmission:
Always engage the parking brake when parking on hills and inclined surfaces, as first gear or reverse may not provide adequate resistance to rolling.
...
You can help prevent corrosion and avoid uneven braking response by gently engaging the parking brake from time to time when coasting to a stop at traffic lights (ensure that you will not pose a hazard to other road users).
I hope this helps.
Best Regards,
Shipo
So unless you are doing that then it is just normal wear and tear. Keep using your parking emergency brakes, it is truly scary how many folks do not use their parking/emergency brakes when they park.
In commercial vehicles, it is the law.
regards,
kyfdx
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That's what I truly love about Edmunds.com...we all don't know each other, but our passion for cars and trucks makes it seem like 1 big family here.
Edmunds rocks!!!!!
The Sandman :-)
My 4 cyl 94 Toyota camry came with H rated tires - amazing but true.
So Costco will only put back on an H. They will not put on a T even.
Most other tire places tell you what came on it originally , but will put on whatever you want.
What's Costco's policy based on?
The first is that the speed rating is based on a lab test. Operating conditions may alter the actual speed capablity of a tire.
For example, using lower inflation pressures lowers the speed capability. Another is driving on a surface that is less than glass smooth.
One way to look at this is what percent of the tire's capability are you using. With an H rated tire, you are using less, and therefore safer, than using an S or a T.
As a general rule, vehicle manufacturers have been caught up the pursuit of handling - trying to make their vehicles responsive to steering inputs - kind of a safety / PR issue. That usually means a higher speed rating.
Hope this helps.
My cousin is also a slow driver he had the same Costco problem with his 4 year old Infiniti Q 45, it had a v rated tire or some other real high rating.
we both bought other places than costco.
To reiterate - yes, you may never approach the upper speed limit of an H rated tire, but that is NOT the issue. H-rated tires are constructed to have better high-speed stability, and possibly more grip (varies with manufacturer, but true when comparing different ratings in the same line of tires from ONE manuf.).
So you WILL benefit from having a higher speed rated tire even when cruising at 60mph and turning sharply at 40mph. Like you may have to do to avoid a potential collision. Buy a lower speed rated tire at your own risk - only if saving approx. $5-10 a tire is worth it
FYI - I upgraded from S rated tires to Z rated tires on my last car. On my current car, I'm on the verge of a move from H rated tires to W rated tires. But that's just me! If you shop around, and follow the reviews, you will not ecessarily pay much more.
-mike
Cars with more agressive spring and strut rates tend to load the tires more and rely on more aggressive tires to make the car handle correctly -
If you use cheaper S or T rated tires, they will wash out and scrub, giving more understeer.
To use a radical example, think of a Corvette's aggressive suspension - the engineers coupled that suspension with 40-45 series, stiff sidewall tires to minimize tire deflection so the car's strong springs and struts could "plant" the tire harder. If you COULD get an S rated 275/40-18 tire (you can't for this very reason, because some cheapskate would put them on his Vette) and put it on instead of a Z or W rated tire, the winpmy sidewall would fold hard under cornering, and you'd lose control. Manke that comparison a little less dramatic, and you have the difference in putting S rated tires on a car that needs H rated tires...
buyer beware
However, it sounds like you are desiring something more - better tread wear, better fuel economy. So to improve those properties, it is advantageous to use a higher inflation pressure. What you sacrifice is ride harshness.
FYI, Ford has for years used just enough inflation pressure to carry the maximum load of the vehicle, and nothing more. They do this in order to get a soft ride. IMHO, this is not good engineering.
3 to 5 psi over the placard is what I recommend as a general rule.
Hope this helps.
-mike
Actually what you wrote just made me cringe. When the Explorer tire blow out situation happened I followed this closely, for my 87 Toyota Landcruiser had the EXACT SAME tire size! So for 18 years I had been running 32-35 psi in my tires while others with the same tire size and I am sure same tire specs run 26 psi ? or 6-9 psi less? or from 19-26% UNDER INFLATED???
So to get you in the ball park if you run 85% of the max side wall tire pressure it will be a good departure point and you can adjust for being too hard or too soft from there. So for example I have been running Michelin LTX's (275-70-16)for over 660k miles. It has a max sidewall rating of 44 psi. So 85% =37/38. I find this too hard so I run it at 35 psi and look to air it up when it hits 32 psi.If I let it go to 26 psi, it would make my heart sink! As another data point the Toyota Dealer that I have been going to for the last 16 years says 32/35 is just fine.
They should stick to reviewing knitting needles and refrigerators.
Consumer Reports' Believer Beware, especially if said Believer is a car enthusiast.
As an auto enthusiast, I do read other magazines such as Road and Track and Car and Driver and appreciate their objective test data and subjective comments about autos. These magazines do not test tires as frequently as does Consumer Reports.
This of course does not prevent something that tests well new to not live up to reliability or durability parameters over time. Truthfully despite a so call black eye, Consumer Reports does report when that happens. They just dont run around practicing self flagellation or are seen in sack cloth and ashen bodied.
An example. I bought a 1985 Toyota Camry based on very favorable testing. I also had had an earlier year Honda Accord stick shift and knew that the automatic Toyota would eat brakes and probably struts in comparison. Again I bought the Honda Accord based on favorable CR tests. For a time owning the Camry was very nice but then it started to become a maintenance nightmare. 1. Gas mileage started to drop, they could fine nothing wrong 2. struts needed changing 3.premature brake pad wear 4 rotor warping
One day I saw some smoke in the headlights while driving at night. I thought it was the car ahead. I stopped when it looked like it might be my smoke. Sure enough as I opened the hood engine oil was firing out of a hole where the metal had failed. So I powered it down and checked the oil an sure enough it was about a quart low so I added and then drove all of 1/2 mile to the Toyota dealership. The next day they said I needed a new manifold, the head gasket was gone, the valves were warped etc etc they estimated 2200. They called back hours later and said well it looks more like 2500. Then when the service advisor called the third time I was almost beside myself. He said you need to tell me you have been having brakes and suspension problems. (Seems there was a secret warranty.) So I said hmmmmmmm and he said, we will take care of it, so he changed the rotors, brake pads, struts, axles. So what should have been close to 3100 in repairs was capped at 2500 and all this under 75,000 miles.
CR later reports that this model year had more than its share of brake rotor suspension problems.
How many times has consumer report tested tires???
2014 Malibu 2LT, 2015 Cruze 2LT,
First, it does not take into account the actual load on the vehicle. This is the MOST important thing to be considered about inflation pressure.
Second, the methodology can lead to a situation where the tire is underinflated. Example: some vehicles require 35 psi to carry the load, and the tires might be marked 35 psi, or they might be marked 44 psi, or even 51 psi. Yet all these tires would have the same maximum load capacity.
The placard, as flawed as it may be, ALWAYS takes the vehicle loading into consideration.
Regarding auto testing, Consumer Reports states that they drive each vehicle for several months and 6000 to 8000 miles. Another factor regarding the things they test is that they “buy” all of their products. This assures that a manufacturer does not get a chance to have a “ringer” put in their test loop. There are no such assurances for car magazines that accept vehicles for testing from manufacturers.
First, it does not take into account the actual load on the vehicle. This is the MOST important thing to be considered about inflation pressure.
Second, the methodology can lead to a situation where the tire is underinflated. Example: some vehicles require 35 psi to carry the load, and the tires might be marked 35 psi, or they might be marked 44 psi, or even 51 psi. Yet all these tires would have the same maximum load capacity.
The placard, as flawed as it may be, ALWAYS takes the vehicle loading into consideration."
First of all I have no problems with your disagreement. I have run 32/35 psi for over 660k miles and basically other than taking in 9-12 nails one year on one set of tires have had no problems and in fact have had 55-90k of treadwear. So clearly if I was running a less than optimum condition, one would not expect those kinds of even wear patterns. While I do not have any direct experience with Ford Explorer tire blow outs (thank God) most of the indications were the tires were so called "under inflated" So for example, all one needs to do is look at the specs for the particular tire it is easy to figure given max tire pressure and max load. Again 85% of that should yield X max load.
So for example mine are 275 70-16 Michelin LTX with max tp of 44 and max load of 2601 .85= 37 psi and max load of 2211 #'s at that pressure. My door also says 32 psi F/R. If I tow a trailer they recommend 35 psi in the rear. As I have stated 37 is too bouncy and rough and I adjusted down to 35 psi and let it sink if I am lazy to 32. Again I would be horrified to run it at 26 psi. Keep in mind that is 32-26= 19% under inflation. So that cuts to the issue of what is considered "under inflation"
What is at issue with Ford (explorer) which is being settled in the courts is whether or not the recommended TP 26 psi was set lower than what the tire manufacturers recommends. I think we will not get a definitive answer from FORD or the sued oem tire vendors for usually part of any settlement is a clause of non disclosure of terms, including technical data such as tp recommendations and procedures and whether or not the prevailing party followed those instructions or not.
Any inflation pressure recommendation has to be directly linked to the actual weight of the vehicle.
Let me point out a couple of flaws:
"275 70-16 Michelin LTX with max tp of 44 and max load of 2601 .85= 37 psi and max load of 2211 #'s at that pressure"
I'm afraid that isn't correct. The maximum load capacity for a P275/70R16 is indeed 2601 #, but it occurs at 35 psi. Increasing the inflation pressure beyond 35 psi is for special circumstances, like high speed driving, which is why the sidewall says 44 psi is the maximum.
Besides, the capacity needs to be derated 10% because it is being used on an SUV.
Not to discount one's experiences, but the experience with one set of tires on one vehicle is not enough to justify a generalization covering all vehicles. Let me site an example:
I obtained access to the actual curb weights, load carrying capacity, and the dimensions of a Ford Super Duty pickup, which had LT235/85R16 load range E tires specified at 80 psi. Regardless of the manufacturer, the maximum load carrying capacity of an LT235/85R16 LR E is 3042 # at 80 psi (single). It turned out that at the worst case, the rear tires needed ALL 80 psi to carry the payload as specified by Ford.
I agree that Ford's spec of 26 psi is horrifyingly low, but my rationale is that the load carrying capacity of a tire at 26 psi is "X" and there ought to be some reserve capacity, and there isn't. This is exactly Firestone's argument.
IMHO, it is generally accepted practice that if you specify a component, it ought to be specified with a larger capacity than is needed. This reduces the probability of overload types of failures. Given that inflation pressures are not well maintained, it just makes sense.
NHTSA did a study shortly after the Ford / Firestone thing. Their survey indicated that 1/3 of all pickups SUV's and vans were 8 psi or more below the placard. I think what people are talking about when they discuss "Underinflation" is this aspect, not what is spec'ed by the vehicle manufacturer.
I guess what I am trying to say is that the vehicle manufacturer goes through some rationale in determining what inflation pressure they put on the placard and they always include the actual weights involved in their calculation. Any pressure recommendation should take this into account, since the source data (the actual axle loading) is not available.
Hope this helps clarify things.
And so do you really expect the typical driver to even attempt to go through the calculations you have just outlined or is what is really missing in the market place a computer program to which you can run thes very "complex" calculations? I know that Ford and Firestone and whoever is on the wrong end of the liability suit would love to get the monkey off their backs BUT....
"NHTSA did a study shortly after the Ford / Firestone thing. Their survey indicated that 1/3 of all pickups SUV's and vans were 8 psi or more below the placard. I think what people are talking about when they discuss "Underinflation" is this aspect, not what is spec'ed by the vehicle manufacturer."
Again if what the NHTSA studies are true then the results totally backs up what I am saying. Keep in mind I mention 19% underinflated. You are mentioning "31%" I know what underinflation I can/want to tolerate and I have stated as such, but again what is really under inflation??? How much is too much. So what did the other 2/3rds run their psi at ? And also as you have indicated 18 psi is do able if I am running on sand!?? Or even on rocks? So I understand what you are saying, but your formula does not answer the fellows question.
So for example the Fords and the OEM tire folks probably dont want to come out with a tire inflation program, again because if someone says they followed the program and here is the print out and it popped anyway again, case closed????
Summary:
Ryoken: What should I use?
CapriRacer: 3 to 5 psi above the placard.
Ruking: 85% of what is written on the SW and adjust from there.
CapriRacer: I don't like the 85% rule, here's why....
Ruking: Well, it works for my situation.
CapriRacer: But it doesn't work for them all.
Case closed!
3/5 above placard 26 being placard= 29/31 So 3/5 because you say so???
vs 32/35.
Lets move on.
And I ruined my first set of Goodyear 245/70r16 by having uneven wear from underinflation (more on outside area of the tread), plus they were really noisy on every turn. Than truck was needed aliment, I got in "old school"(very good) aliment shop and guy told 26 is to low, you have to run from 35 to 40, it will be a little harsh ride but hay you bought a truck. I am now on my second set, I have Michelin LTX 245/70r16 at 35psi for about 40k mi and I got even wear and no noise at all.
On my another car I run Michelin MXV-4 205/60R15 at 38psi(placard front=32,rear=28) for last 90k mi, I get even wear, better MPG, longer tire life. Well, I am not sure if you can do this with some no-brand tires, but with good brand name, like Michelin, I see no problem run +5/7 psi.
Rollovers: Why do they shoot from behind, and not show how hard the driver is yanking the wheel, etc. Their testing is marginal at best!
As for advertising... Hello Enron Under the Table deals....
Tires and cars: They test them, and then take the lowest common denominator as their car/tire of choice. Never a real good car or real bad one, but an average one that would go well with their toasters and blenders.
-mike
I get the impression that 26 is safe, but is the absolute bottom with no margine of safety, so make sure it never goes under, not even a little bit. I'll run it in the low 30's for a bit and see if the ride comfort is acceptable.
Going above 35 definately makes it a bumpy ride. The only time I do that is for autocross days with the other car.
And you ought to maintain the front / rear pressure split. That way the handling doesn't change significantly.
I concluded I couldn't trust their testing and cancelled my subscription.
I have recently become aware that the folks at CR that do tire testing are former Pirelli - Armstrong engineers. They arrived many years after I cancelled my subscription. Hopefully their knowledge and experience has resulted in meaningful, "apple to apple" tests.
I have tried to research the actual tire testing that CR performs, but have run into road blocks - in particular, a lack of a subscription.
Before I write a check, does anyone know if CR supplies any details about the actual tests they perform?
Thanks in advance.
-and the box store tires wal mart costco etc are unknown names.Whats a goodyear arriva relate to? - you do not know what regular tire they relate to..
I trust CR more than tire rack surveys. cr will test like 20 brands in one category on one car over a number of days and I really think that give you a good stackup of their COMPARITIVE stopping handling etc. It does not tell you if the tires wear well or if they stay round. many complaints about tires like Dunlops are they are great for 10k miles then get noisy.
the tire rack surveys are not useful to me - one person a tire is great and the next says they suck???????
Whats the answer ?I don't know.
the tire people have you where they want you - dependant on advertising. Oh Buy Michelin you say? - most of those I have owned ride hard.
2) Tirerack does test tires, in addition to the survey results. Their tests are skewed towards performance tires, generally. But, that also seems to be their customer base. The performance tires were tested on a BMW 330i. There is a lot of good information from the tests, much more so than the surveys.
regards,
kyfdx
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For other CR auto/tire testing. I do a TSD/scavenger hunt type of road rally 4 times per year. One member shows up with a different brand new car every time (I started noticing this 6 years ago)turns out he works for CR. These are test vehicles and they have to drive them like they would their own car. The rally are LOW SPEED about 30 mph mostly) but go down some REAL bumpy roads at times. I just thought it was awesome to talk to him and often think hmmmmm that would be a great job. I always chuckle some when I read the auto testing and see pictures of the cars they drove and then read the good and bad points.
The survey with the colored dots!??
Those are surveys of CR subscribers which may or may not be a representative sampling of all owners.
tidester, host
I can understand the results you get of of Tire rack and similar surveys. And my past experiences with CR are just that - past!
Since I get asked about these ratings on a regular basis, I think it would be nice if I knew how they get them. The last time I looked, they didn't supply any details - only the results.