Discount Tire Direct vs. Tirerack
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bottgers,
By expressing that sort fo blind faith in OE door sticker I would assume that you also ALLWAYS use exact OE tires as replacements when buying replacements ? What could possibly be as good as what the manufacturer chooses?
Although I'm one of those fairly stupid knuckle dragging tire installers, after 30 years of puttin em on and takin em off seems I've noticed better tire life for folks who run high. Nothin scientific just barely can count past fingers and toes.
Bob
quote:Must be hard to count on your fingers with those knuckle callouses from dragging them on the ground.
Originally posted by alreadygone: Although I'm one of those fairly stupid knuckle dragging tire installers, after 30 years of puttin em on and takin em off seems I've noticed better tire life for folks who run high. Nothin scientific just barely can count past fingers and toes. Bob
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Have you noticed any differences in wear patterns on slightly under or over inflated tires on cars with good wheel alignment?Seem to see most edge wear on underinflated. Almost never see tires run overinflated enough to cause abnormal wear unless on too narrow rims (wich causes abnormal wear no matter what pressure).
Really, under or over must be pretty excessive before any real problems show up.
Bob
quote:Good point. It's been my experience that OEM tires have been the WORST tires I've had. I inflated my tires to 35 psi last night, and you guys were right. They do feel a lot better at this pressure. Not much difference in ride smoothness, but a NOTICEABLE difference in rolling resistance. There seems to be a bit less road noise too. I will check my fuel milage during my next tank of gas. I can definitely foresee a reduction in wear just from the reduced rolling resistance. Sorry about the statement I made about the tire guys. No pun intended. You guys definitely know what you're talking about. Thanks for the info.
Originally posted by alreadygone: bottgers, By expressing that sort fo blind faith in OE door sticker I would assume that you also ALLWAYS use exact OE tires as replacements when buying replacements ? What could possibly be as good as what the manufacturer chooses? Although I'm one of those fairly stupid knuckle dragging tire installers, after 30 years of puttin em on and takin em off seems I've noticed better tire life for folks who run high. Nothin scientific just barely can count past fingers and toes. Bob
quote:Allright you guys converted him! I'm sure you will notice a noticeable increase in fuel economy. My OE recommendation is 32/30, I ran 35 all around on my last set of tires, got great MPG, and they lasted longer than the treadlife warranty. My new tires are rated up to 44psi and I run them at 40, wear is even and mileage is good. The only downside I can find is that sharp bumps in the road are more harsh, but I can live with that.
Originally posted by bottgers: I inflated my tires to 35 psi last night, and you guys were right. They do feel a lot better at this pressure. Not much difference in ride smoothness, but a NOTICEABLE difference in rolling resistance. There seems to be a bit less road noise too. I will check my fuel milage during my next tank of gas. I can definitely foresee a reduction in wear just from the reduced rolling resistance.
Someone said: "I don't see any possible benefit by running with higher than normal pressures."
You'll get more mpg with higher inflation.
I run 3 psi higher than doorsticker and adjust from there. Improves many things
I have been playing around with various different pressures and I seem to like 33 the best. 35 seems a bit too harsh of a ride, but 33 seems to be high enough to still reduce the rolling resistance, while maintaining a fairly decent ride.
At the winery where I work as Associate Winemaker, there's a Nitrogen tank in the lab with long hose and pressure regulator. Hose.. as in normal air line hose with chuck connector. I use it to test the membrane filters after a bottling run and after they have cleaned the filter in a mixture of sodium hydroxide in water, and flushed.
I have heard that Nitrogen is excellent for tires, holds the pressure steadier and doen't leak like regular air (nitrogen is larger molecule). Would it be advantageous to put in Nitrogen? We also have CO2, but I REALLY doubt that would have any great benefit, unless you needed to spritz up a soda out in the boonies somewhere..
You've identified one of the 2 advantages of using nitrogen inflation - less leakage - and the second is that it slows down oxygen degradation - which may or may be be a problem in your area as this is pretty much temperature related.
The other things that have been attributed to nitrogen - fuel economy, wear, and durability - are related to the inflation pressure - and, yes, if you don't check your inflation pressure but once every 2 years, nitrogen will be better. But if you check like you are supposedto - every month - then you won't experience any advantage at all!
So if it is difficult to arrange for a nitrogen filling station, don't bother.
BTW, CO2 is not as inert as nitrogen, so it doesn't offer the advantages. Plus, it does have oxygen as part of it's formula, so there will be free radicals of oxygen, so you kind of lose that benefit.
Small-Mart just put on 2 new tires in front for me, the Goodyear Viva 2. The tread design looks very good with lots of lugs and slices for grabbing slicker road surfaces. However, I checked the air in the tires at noon. They say on the sidewall, max pressure of 44 PSI, and they had 26. So I upped it to around 33-35 PSI. Back had 34 so I dropped them (BG Goodrich) down to 28. My logic is this: one of the reasons rear tires develop such problems with cupping is the rear end is obviously a lot lighter, unless you are hauling a lot of 100 # feed sacks in there.
I know that lower pressure makes the tire less "bouncy", so it should stand to reason that the less pressure in the rear will help, (not eliminate) the little bounces. Almost flat tires hardly bounce at all, but get hot from the sidewalls flexing so much.
quote:I thought we established that your problem with "cupping" was due to insufficient rotation, especially on the part of the previous owner. Personally, I disagree that rotation was the problem as I think your "cupping" problem was due to misalignment, and was aggravated by insufficient rotation. But low inflation pressure aggravates the situation, too! So I think your logic is faulty. Here's something to chew on: Increasing inflation pressure stiffens up a tire. Stiffer tires gets better wear. It's been my experience that even though you may experience uneven wear (like wear in the shoulder or shoulders), the net effect is that the tires last longer. Now I'm not sure which vehicle we are talking about, but if it's the Park Avenue, doesn't the placard call for 30 psi?
Originally posted by Nebraskan: Small-Mart just put on 2 new tires in front for me, the Goodyear Viva 2. The tread design looks very good with lots of lugs and slices for grabbing slicker road surfaces. However, I checked the air in the tires at noon. They say on the sidewall, max pressure of 44 PSI, and they had 26. So I upped it to around 33-35 PSI. Back had 34 so I dropped them (BG Goodrich) down to 28. My logic is this: one of the reasons rear tires develop such problems with cupping is the rear end is obviously a lot lighter, unless you are hauling a lot of 100 # feed sacks in there. I know that lower pressure makes the tire less "bouncy", so it should stand to reason that the less pressure in the rear will help, (not eliminate) the little bounces. Almost flat tires hardly bounce at all, but get hot from the sidewalls flexing so much.
Yes, CapriRacer we have come to some general idea that the cupping was due largely to lack of good tire rotation. However, I'm with you on the thought that there may be other circumstances. This is on the 1996 PA and yes it says on the door, 30 PSI. Tires are rated different pressure. Which do you go by, the door or the tire?
I took the Park Avenue into the shop last week for flushing the brake fluid and replacing with Valvoline synthetic. I asked the shop to inspect the tie rod ends and the ball joints to see if they needed replacing soon. Both came back with good reports. I asked about the shocks, but the shocks bounce right back after letting go and there is no fluid or other leakage on the struts.
Perhaps loose bearing? Or it could be out of alignment, but that would produce something a bit different that cupping, like inside or outside wear or feathering. I don't doubt about the stiff tires, that is why I'm running 34 or so in the front. I think they might make better mileage that way and the front is basically where all the weight is on the car.
The back tires are the ones that were cupped from the original. Next set of tires will probably be Yokohama tires.
Nebraskan,
What is written on the sidewall of the tire is subject to a government regulation. The regulation is worded badly and there are different takes on what is supposed to be written there. So you will find some differences.
But there is one constant. And that is that if you use the same tire size as listed on the placard, then the placard inflation pressure is appropriate. Personally, I like to to use 3 to 5 psi above that value, because the only downside is some loss of ride harshness, but I get better furel economy, better steering crispness, better tire wear, better tire durability, better wet traction, better snow traction... and the list goes on.
But you have one misconception that needs to be cleared up.
"Cupping" is technically related to bad shocks or out of balance, but the term "cupping" is generally misused to include some irregular wear patterns like diagonal wear, spot wear, even feathering. Many of these are caused by misalignment.
I can tell you that your Park Avenue is somewhat notorious for generating irregular wear (technically not cupping) on the rear axle and while I don't have the data to back it up, my gut reaction is that this is due to a toe problem.
I checked the toe on the back and it is toed in 3/8" which I would not think is too excessive. 1/4" would be nice as that would be just 1/8" less than the 3/8" is now.
The tread was like this: Hiher on the leading lug and tapering back to the traling end of the lug, then the gap then next lug, high enough to feel, and then the slight taper on the lug... so on and so forth.
quote:I think you just confirmed what I was saying. Those toe in values sound HUGE!!!! to me. But the one thing you didn't tell me was what the target (nominal) value is supposed to be. I have found that toe in has to be within 1/32" PER SIDE or there might be wear problems. That would be a 1/16" total toe, so a quarter sounds 4 times too wide - but again what is most important is what the target value is supposed to be.
Originally posted by Nebraskan: I checked the toe on the back and it is toed in 3/8" which I would not think is too excessive. 1/4" would be nice as that would be just 1/8" less than the 3/8" is now.....
Between 1/16" to 1/8" toe is nominal for the rear Park Avenue.
nitrogen is dry...where as air normally isn't. Dry air is cheaper than a nitrogen system (the brannick system is about $8,000 where an air dryer and cooler is about $3000). most racecars nowadays use dry air (specifically pirelli for ALMS races), as they have found that moisture in the tires makes for one too many of a variable to try and control.
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