| macphanatic |
| I'm thinking of inflating my tires a few more psi for handling/fuel economy purposes. Anyone else doing this? |
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| ptsmh73 |
| I believe most are running higher PSI than on the door label. I run mine at 35 PSI. |
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| Nathan_P |
| I run my tires @ 38psi |
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| mmmmark |
I run mine 34 or 35 cold.
I'd be concerned about running 38, unless that is "road pressure".
If 38 is cold pressure, that could be well over 40 (just a SWAG) hot. That is potentially dangerous and more prone to hydroplaning or slippage in marginal conditions.
Radials perform best when they have just a bit of give in them. |
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| Roger |
| These numbers don't mean anything unless you know what the tire manufacturer's max sidewall pressure is. |
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| macphanatic |
| Have any of you noticed improved mpg after upping tire pressure? |
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| CMasten |
Im in So Cal, this summer I tracked my mileage with my new CTs and saw almost exactly 1pmg more at 36 than at 32. Average of 8 fillups
I just put new Michelins on my wifes Ody and have seen about the same with the same driving conditions on hers as well. Average of 6 fill ups |
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| N_Jay |
quote:
Originally posted by mmmmark
I run mine 34 or 35 cold.
I'd be concerned about running 38, unless that is "road pressure".
If 38 is cold pressure, that could be well over 40 (just a SWAG) hot. That is potentially dangerous and more prone to hydroplaning or slippage in marginal conditions.
Radials perform best when they have just a bit of give in them.
The safe pressure is listed on the sidewall, and is often over 40 (typ 44).
Either way it is measured as a "cold" pressure and already accounts for the increase from heating.
Also, under many conditions, higher pressures handle better, including reducing hydroplaning. |
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| larryziegler |
| I increased my pressure from 35-38 psi and have seen a 1 mpg increase in highway mileage (from 22 mpg - 23 mpg). |
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| mmmmark |
quote:
Originally posted by N_Jay
Also, under many conditions, higher pressures handle better, including reducing hydroplaning.
Why do I find wording like this in many places on the net?
OVER INFLATION: An over-inflated tire will balloon on the road surface. The center of the tire will appear more worn than the edges. It will not corner as well and is more prone to hydroplane. This is because the tread meant to channel the water is not completely in contact with the road surface.
Also:
If your tires are over inflated by 6 psi, they could be damaged more easily when running over pot holes or debris in the road. Higher inflated tires cannot isolate road irregularities well causing them to ride harsher.
Upping the pressure is only good....to a point. |
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| N_Jay |
quote:
Originally posted by mmmmark
Why do I find wording like this in many places on the net?
OVER INFLATION: An over-inflated tire will balloon on the road surface. The center of the tire will appear more worn than the edges. It will not corner as well and is more prone to hydroplane. This is because the tread meant to channel the water is not completely in contact with the road surface.
Also:
If your tires are over inflated by 6 psi, they could be damaged more easily when running over pot holes or debris in the road. Higher inflated tires cannot isolate road irregularities well causing them to ride harsher.
Upping the pressure is only good....to a point.
I guess it is all in the definition of "over-inflation".
I have rarely seen radial tires where even at max pressure do not still have a little sidewall bulge.
While significantly narrowing the tread by over inflation (like would happen with bias-ply tires) would definitely decrease handling, the higher pressures also mean higher contact pressures and will therefore (as it has been explained to me) be less likely to hydroplane. (higher contact pressure will displace water faster as ling as there are tread channels for it to displace through.
think of it as the opposite of what happens when you air-down for sand.
When I used to autocross, everyone ran their tires right up to the limit. |
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| macphanatic |
| More pressure means a smaller contact patch. Therefore, you should get better gas mileage. You also get better traction in snow and rain as the force applied per square inch is greater (same weight exerted over a smaller area). Airing down works for sand because you don't want to dig in, you want to float (for lack of a better term). |
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| N_Jay |
quote:
Originally posted by macphanatic
More pressure means a smaller contact patch. Therefore, you should get better gas mileage. You also get better traction in snow and rain as the force applied per square inch is greater (same weight exerted over a smaller area). Airing down works for sand because you don't want to dig in, you want to float (for lack of a better term).
Well put.
And I don't think there is a better tire.
Maybe that is why sand tires are called "Flotation Tires"? |
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| krygny |
quote:
Originally posted by Roger
These numbers don't mean anything unless you know what the tire manufacturer's max sidewall pressure is.
:confused:
The max pressure on the sidewall is just that - the maximum pressure the tire is designed to handle. It has nothing to do with anything else.
Most tire manufacturers will not suggest a pressure. They suggest following the recommendation of the vehicle manufacturer. Honda recommends 32 psi. I run at 34-36. |
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| Roger |
quote:
Originally posted by krygny
:confused:
The max pressure on the sidewall is just that - the maximum pressure the tire is designed to handle. It has nothing to do with anything else.
Most tire manufacturers will not suggest a pressure. They suggest following the recommendation of the vehicle manufacturer. Honda recommends 32 psi. I run at 34-36.
What I was trying to say is that if you run the Honda rec 32 in a tire that had a max press of 34 you would be close to the max rec pressure (and what I would run). If you ran 32 in a tire rated for 44 you would be underinflated (IMO).
To just say you run "x" pressure and not know what the max pressure of the tire is to me is not a valid comparison.
I always run mine close to the max sidewall pressure (cold). Doesn't give the best ride but for me it gives the best tread life, handling and fuel mileagae. Remember this is what I do, not saying everyone else should, just my opinion. |
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| Roger |
I'll also throw this out there. In the grand scheme of things it probably really doesn't matter much what pressure you run as long as you check it frequently and never run under inflated.
How many stories have you heard where someone suffered a blowout from an overinflated tire? I'd wager that most are due to underinflation which means heat therefore blowout time.
Set them to where you're comfortable (I like to be near the max sidewall pressure when cold) and check them (while cold) often. This will ensure long life (the tires and you own) as well as maintain the best fuel economy. |
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| krygny |
quote:
Originally posted by Roger
What I was trying to say is that if you run the Honda rec 32 in a tire that had a max press of 34 you would be close to the max rec pressure (and what I would run). If you ran 32 in a tire rated for 44 you would be underinflated (IMO).
To just say you run "x" pressure and not know what the max pressure of the tire is to me is not a valid comparison.
I always run mine close to the max sidewall pressure (cold). Doesn't give the best ride but for me it gives the best tread life, handling and fuel mileagae. Remember this is what I do, not saying everyone else should, just my opinion.
You're entitled to your opinion and they're your tires so you can do whatever you want, but the maximum recommended pressure of a tire has nothing to do with its intended application. In fact, they're intended to be used well below the maximum, not at or near it. |
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| krygny |
quote:
Originally posted by Roger
I'll also throw this out there. In the grand scheme of things it probably really doesn't matter much what pressure you run as long as you check it frequently and never run under inflated.
How many stories have you heard where someone suffered a blowout from an overinflated tire? I'd wager that most are due to underinflation which means heat therefore blowout time.
Set them to where you're comfortable (I like to be near the max sidewall pressure when cold) and check them (while cold) often. This will ensure long life (the tires and you own) as well as maintain the best fuel economy.
Radial tires are designed to maintain even pressure across the tread. If you over-inflate them (and approaching the max is over-inflating), the sidewalls become too firm and the inside of the tread will tend to lift up around turns (like the old bias-ply tires). I doubt that inflating them to the max pressure significantly improves tread life (and may actually reduce it). Also, at those pressures, the performance of the tire in all conditions (dry, wet, snow) will be adversely affected.
But, as I said, they're your tires. |
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| netman88 |
My '06 said to have it at 32psi so I'm running at that.
Not sure why shall we run it higher?
It will warm up to be higher for sure. |
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| N_Jay |
quote:
Originally posted by Roger
What I was trying to say is that if you run the Honda rec 32 in a tire that had a max press of 34 you would be close to the max rec pressure (and what I would run). If you ran 32 in a tire rated for 44 you would be underinflated (IMO).
It may be your opinion, but it is factually incorrect.
The recommended pressure has to do with the weight on the tire and the contact area. (all else being the same)
The contact area is closely related to the tire size, so with a given size the recommended pressure stays the same no matter what the maximum pressure rating is.
quote:
Originally posted by Roger
To just say you run "x" pressure and not know what the max pressure of the tire is to me is not a valid comparison.
Yes it is, as stated above.
quote:
Originally posted by Roger
I always run mine close to the max sidewall pressure (cold). Doesn't give the best ride but for me it gives the best tread life, handling and fuel mileagae.
Yes, almost all attributes, (handling, wear, gas mileage, etc.) improve with added pressure up to the safety limit of the tire.
The one attribute that suffers in ride comfort.
(For those that want to argue, yes handling can be slightly decreased if your tires are overinflated to the point they lose some sidewall compliance, but that is hard to do and stay under the max pressure rating.)
quote:
Originally posted by Roger
Remember this is what I do, not saying everyone else should, just my opinion.
It is amazing when the wrong reason gets you to the right answer (Well, maybe it is not so amazing considering this is how Myths and superstitions are usually born) |
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| N_Jay |
quote:
Originally posted by krygny
In fact, they're intended to be used well below the maximum, not at or near it.
IN FACT!!!
They are intended to be used ANYWHERE UP TO, but never over the maximum inflation rating. |
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| krygny |
quote:
Originally posted by N_Jay
IN FACT!!!
They are intended to be used ANYWHERE UP TO, but never over the maximum inflation rating.
If that were true, the performance of the tire under all conditions would be exactly the same at 44 psi as it would be at 32 psi. |
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| larryziegler |
quote:
Originally posted by krygny
If that were true, the performance of the tire under all conditions would be exactly the same at 44 psi as it would be at 32 psi.
Not quite true. Add 1500 lbs of cargo/people/hitch weight and a 3500 lb trailer, and 32 psi is IMO, a woefully underinflated tire, as additional heat will build up on that tire, which could cause tire failure. A reason Honda uses its 32 psi recommendation is to best balance economy and riding comfort of the vehicle. Change the load dynamics and you change the necessary air pressure requirement. On the flipside, as was earlier said, take the vehicle out on the sand and 32 psi or greater will try to dig thru the sand, whereby deflating the tire to 15 pounds will create a much softer footprint whereby the tire will attempt to float on top of the sand. Inflate the tire to the max 44 psi for road use, and what you will get is best possible fuel economy and the harshest/stiffest possible ride due to the hardness of the tire. In the end, depending on how you are using your vehicle, your tire pressures should be adjusted to reflect the usage. |
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| N_Jay |
quote:
Originally posted by krygny
If that were true, the performance of the tire under all conditions would be exactly the same at 44 psi as it would be at 32 psi.
How do you figure?
The tires are designed to be used over a wide variety of applications and conditions, such as, load weight, road speed, inflation pressure, running temperature, etc.
As any of these (and many other variables) are changed, the performance will be affected.
Inflation is just one parameter, and yes changes in inflation will effect changes in overall performance, HOWEVER, with that being said, the tire is designed to be used over a wide range of pressures UP TO, BUT NOT OVER the specified maximum.
Is that so hard to understand? |
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| mmmmark |
Recommended pressure takes into account, comfort, which can be sacrificed for higher mileage.
BUT, keep in mind that the recommended pressure also is what the suspension is tuned to handle. Putting too much pressure in could possibly remove some of the "give" that makes the vehicle safe. Keep in mind I'm talking about the average driver here.
I think that gauging your pressure off of the MAX is starting at the wrong end of the spectrum. Start with the recommended and work up to a happy medium for comfort, performance and safety. (IMHO) |
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| N_Jay |
quote:
Originally posted by mmmmark
Recommended pressure takes into account, comfort, which can be sacrificed for higher mileage.
BUT, keep in mind that the recommended pressure also is what the suspension is tuned to handle. Putting too much pressure in could possibly remove some of the "give" that makes the vehicle safe. Keep in mind I'm talking about the average driver here.
I think that gauging your pressure off of the MAX is starting at the wrong end of the spectrum. Start with the recommended and work up to a happy medium for comfort, performance and safety. (IMHO)
Well my rule of thumb is made up of a few "Sub-rules".
1) The manufacturers recommendation is the safe minimum.
2) The sidewall rating is the safe maximum.
3) Higher pressures are preferred over lower pressures (except for ride comfort.
4) Most drivers can not tell a 2 PSI change at all.
5) Never trust a consumer gauge to be better than +/- 2 PSI.
All this comes to my "Rule of thumb" of;
Never go below 2 PSI above the manufacturer's recommendation, and never go above 2 PSI below the sidewall rating.
IM(not so)HO, I like 2/3 to 3/4 the way between these two limits, and don't bother futzing with changes of less than 2 PSI.
So book 32 PSI and door 44 PSI, means a range of 34 PSI to 42 PSI, with midpoint of 38 PSI, and 3/4s of 40 PSI.
So there you go. (Please note, I like a taught ride.) |
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| Roger |
| And 42 is exactly what I run in my CT's, 44 sidewall max. Works for me. |
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| krygny |
quote:
Originally posted by N_Jay
...
Is that so hard to understand?
Look again at the name of the thread. Nobody was talking about heavy loading, tongue weight, or running at the max GVWR. We were talking about general all-the-time running pressure. And we're talking about the Honda Pilot, not every conceivable use of a particular tire. There are no [safe] conditions that would require inflating the tires to 44 psi. And there are no conditions where the tires would perform better at 44 psi than at some pressure closer to 32. |
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| Nathan_P |
quote:
Originally posted by krygny
Look again at the name of the thread. Nobody was talking about heavy loading, tongue weight, or running at the max GVWR. We were talking about general all-the-time running pressure. And we're talking about the Honda Pilot, not every conceivable use of a particular tire. There are no [safe] conditions that would require inflating the tires to 44 psi. And there are no conditions where the tires would perform better at 44 psi than at some pressure closer to 32.
It is all up to the driver's preferences.
The fact is that the "maximum recommended pressure" in the stock Goodyear Integrities is 44psi. I don't understand how everyone is saying that even everything up to that pressure isn't safe or it would lead to uneven tire wear :8: It is within the recommendations of the tire manufacturer and I trust that they have done enough testing on their product to know what is safe on wet roads, etc.
I understand that Honda suggests 32psi but agree with most here that say that Honda's recommendation is more based on ride comfort than anything else. For everyone saying that they will only run @ 32psi because that is what Honda suggests...good for you. I personally agree with larryziegler that with a few people in the back and carrying cargo...32psi would make me nervous because of underinflation. I also agree w/ N_Jay's "rules of thumb" and was taught nearly the same thing by my father.
I ran 32psi when I first got my Pilot & didn't like it because I prefer a stiffer ride so I upped it to 35psi & felt virtually no difference between the two pressures. So now I stick with 38psi and have the ride that I prefer and also benefit w/ a few MPG better fuel economy as a bonus. |
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| N_Jay |
quote:
Originally posted by krygny
Look again at the name of the thread. Nobody was talking about heavy loading, tongue weight, or running at the max GVWR. We were talking about general all-the-time running pressure. And we're talking about the Honda Pilot, not every conceivable use of a particular tire. There are no [safe] conditions that would require inflating the tires to 44 psi. And there are no conditions where the tires would perform better at 44 psi than at some pressure closer to 32.
This is the quote I was addressing
(You can figure this out by noting that it was the quote I included in my post.)
quote:
Originally posted by krygny
If that were true, the performance of the tire under all conditions would be exactly the same at 44 psi as it would be at 32 psi.
So now, can you explain how it makes any sense?:confused: :rolleyes:
There are many conditions where the tires will perform better at 44 than at 32.
Unless you believe that 32 is a magic number where all factors mysteriously peak at the same point, rather then the fact that it is nothing more than a compromise point where Honda believes that overall the attributes are good enough and safe. |
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| mmmmark |
HIGH pressures like 38+ will save you maybe 1 mpg or so, and will increase the life of your tires.
It will NOT provide safety benefits and will NOT be safer on wet or snowy roads. Read the web people, all the experts can't be wrong!
If you are driving by yourself, do whatever you want, but if you are driving with a wife and/or kids who don't have a say-so in this, do the safe/sane thing and don't run with such high pressures. You put them and the rest of us at risk.
peace out--put a fork in it, i'm done |
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| N_Jay |
quote:
Originally posted by mmmmark
HIGH pressures like 38+ will save you maybe 1 mpg or so, and will increase the life of your tires.
It will NOT provide safety benefits and will NOT be safer on wet or snowy roads. Read the web people, all the experts can't be wrong!
If you are driving by yourself, do whatever you want, but if you are driving with a wife and/or kids who don't have a say-so in this, do the safe/sane thing and don't run with such high pressures. You put them and the rest of us at risk.
peace out--put a fork in it, i'm done
Glad you are done.
Now others can do some reading and "put a fork" into a few myths.
Check out this chart for aircraft.
http://www.mountainflying.com/hydroplane.htm |
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| Nathan_P |
quote:
Originally posted by mmmmark
HIGH pressures like 38+ will save you maybe 1 mpg or so, and will increase the life of your tires.
It will NOT provide safety benefits and will NOT be safer on wet or snowy roads. Read the web people, all the experts can't be wrong!
If you are driving by yourself, do whatever you want, but if you are driving with a wife and/or kids who don't have a say-so in this, do the safe/sane thing and don't run with such high pressures. You put them and the rest of us at risk.
peace out--put a fork in it, i'm done
So are you telling me that ALL the experts say that 38psi is dangerous? Please show me.
I don't think anyone here has said that 38psi is any safer than 32psi. I don't believe, however, that it is any less safe.
What are you talking about by saying "such high pressures"? The maximum recommended pressure for the Goodyear Integrities is 44psi. 38psi is 6 less than what Goodyear has rated the tire for. That is hardly dangerous. |
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| macphanatic |
You can't believe everything that you read on the web. There are a lot of self proclaimed experts out there that don't know what their talking about.
I learned about this 20 years ago in a Prime Movers class during my Mechanical Engineering curriculum. The smaller the tire contact area, the better traction in wet and snowy conditions. This assumes that there is enough tread to force water or snow out. For icy conditions (only ice with no rain/snow accumulations), you actually want to have no tread for best traction, assuming no studs are being used.
Tire manufacturers provide a maximum pressure to warn users as to the strength of the tire structure. Realize that the tire will actually take a much higher pressure than listed. Engineers tend to like a safety factor of 2+, this would mean that a tire with a rated max pressure of 44 psi should be able to handle 88 psi. However, not being in the tire manufacturing business, I don't know what the industry norm for safety factors is. Please note that I am talking about cold inflation pressures here, as the rated numbers for hot pressures would be higher. For a container that doesn't change volume, the pressure change due to temperature change is simple. However, a tire's volume changes a bit, so it is not really straight forward. Think about it, putting the actual max pressure on a tire in the US would be suicidal from a legal perspective. |
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| colorider |
quote:
Originally posted by macphanatic
You can't believe everything that you read on the web. There are a lot of self proclaimed experts out there that don't know what their talking about.
+1
:7: |
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| N_Jay |
quote:
Originally posted by colorider
+1
:7:
Someone call? :D :eek:
:2: :2: :2: :2: |
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| colorider |
quote:
Originally posted by N_Jay
Someone call? :D :eek:
:2: :2: :2: :2:
HaHa!!! But you know how much I enjoy tire pressure and oil threads!!!
:D |
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| N_Jay |
quote:
Originally posted by colorider
HaHa!!! But you know how much I enjoy tire pressure and oil threads!!!
:D
Don't forget air filters, Fuel economy, and most performance accessories.
I love shooting myths! |
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| StarBlazer |
| When I picked up my Pilot in March, the tire pressure was set to 40. Who knows if it was purposely done this way or not however they were all consistently set at 40. I run them at 34 now according to my gauge. This will allow me the +- 2 factor. |
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| N_Jay |
quote:
Originally posted by StarBlazer
When I picked up my Pilot in March, the tire pressure was set to 40. Who knows if it was purposely done this way or not however they were all consistently set at 40. I run them at 34 now according to my gauge. This will allow me the +- 2 factor.
They are shipped at 40+ PSI to prevent flat spotting of the tires and to withstand the load of being tied down during shipping.
The dealer is supposed to adjust them down.
It is specifically called out in the Pre Delivery Instructions, and I would give the dealer hell (nicely) and ask for a free first oil change since they did not do some work that they were PAID to do (Part of delivery charge on your invoice). |
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| NJGuy |
ah, another thread on tire pressure.
Before jumping into the "best tire pressure" debate, I'll answer the question of the original poster. I'm happiest keeping my Goodyear Integrities at around 36 PSI cold. The ride is firm but not excessively harsh. I also try not to let them fall below 34 PSI.
I don't check my tire pressures monthly like I should, but if I feel like the handling gets too squishy or the vehicle is a bit more bouncy I check and adjust the pressures. At the pressure I like, I feel like I get the best mix of ride, handling, fuel economy, and tire wear. Everybody has their own tire inflation "sweet spot".
quote:
BUT, keep in mind that the recommended pressure also is what the suspension is tuned to handle. Putting too much pressure in could possibly remove some of the "give" that makes the vehicle safe. Keep in mind I'm talking about the average driver here.
I haven't thought much about this topic as much as the long term effects of running higher tire pressures. Would running higher pressures cause premature wear on certain parts of the vehicle, particularly the suspension components? I figure that if a tire has an elevated tire pressure, it has less of an ability to flex, displace bumps, and absorb some shock, allowing a higher amount of those impulses to be transmitted into the suspension system. This is a question that I've really never seen come up turing tire pressure threads in any forum I've read. I know alot of you are car guys, so I'd be interested to hear what some of you would say. |
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| mikesrc |
28 PSI I like a nice ride. Thats just above what sets off the tire gauge deal. HAVE not seen any increase or decrease in MPG that would cause me any heartburn. 2 long trips this summer one did 21.9, the other 22.3. Good enough for me!!
Mike in OKC |
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| N_Jay |
quote:
Originally posted by mikesrc
28 PSI I like a nice ride. Thats just above what sets off the tire gauge deal. HAVE not seen any increase or decrease in MPG that would cause me any heartburn. 2 long trips this summer one did 21.9, the other 22.3. Good enough for me!!
Mike in OKC
I would NEVER go under the recommendation, especially on long trips and with any load.
Welcome to Ford Explorer roll-over territory! |
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| xGS |
quote:
Originally posted by macphanatic
You can't believe everything that you read on the web. There are a lot of self proclaimed experts out there that don't know what their talking about.
For icy conditions (only ice with no rain/snow accumulations), you actually want to have no tread for best traction, assuming no studs are being used.
This individual clearly knows far more about tire design than the team of engineers at Bridgestone who created the Blizzak winter tires. |
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| macphanatic |
| xGS, I meant for driving on ice that a small contact patch with no tread would work best. The problem is that if you were then to drive in snow, rain or water puddles, your traction would be horrible. In most cases, the theoretical best solution can't be used because of limited application. That is why goal of tire design is often to balance to best of many parameters. If you want the best snow/ice tire try a set of Nokian tires. The compounds that make the tires so good in these conditions also tend to reduce the mileage that you can get out of them. |
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| mmmmark |
quote:
Originally posted by macphanatic
In most cases, the theoretical best solution can't be used because of limited application.
Tell that to N_Jay who is using airplane information as a useful comparison. ;)
Sorry, I couldn't resist. |
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| xGS |
quote:
Originally posted by macphanatic
xGS, I meant for driving on ice that a small contact patch with no tread would work best. The problem is that if you were then to drive in snow, rain or water puddles, your traction would be horrible. In most cases, the theoretical best solution can't be used because of limited application. That is why goal of tire design is often to balance to best of many parameters. If you want the best snow/ice tire try a set of Nokian tires. The compounds that make the tires so good in these conditions also tend to reduce the mileage that you can get out of them.
What Bridgestone determined is that the surface of the ice under the tire melts slightly creating a thin film of water which must be dispersed in order for the tread to grip - which is unlikely to occur using a tire with no tread (pattern).
The major shortcoming of Nokian tires is their second-rate uniformity. |
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| N_Jay |
quote:
Originally posted by xGS
This individual clearly knows far more about tire design than the team of engineers at Bridgestone who created the Blizzak winter tires.
Hu?
What does one statement have to do with the other? |
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| N_Jay |
quote:
Originally posted by mmmmark
Tell that to N_Jay who is using airplane information as a useful comparison. ;)
Sorry, I couldn't resist.
LOL; You work hard to twist things till you think you are right. Don't you. :rolleyes:
1) Please explain in any sensible manner how the theory and practice is different in this case.:4:
2) Please note the reference in the the referenced page that it DOES apply to car tires.:4: |
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| klinger |
Will i really get better mileage going from 32 psi to 35. In turn will i damage the tires. I rotate every 6000 miles.
Thanks for any info |
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| mmmmark |
quote:
Originally posted by N_Jay
LOL; You work hard to twist things till you think you are right. Don't you. :rolleyes:
1) Please explain in any sensible manner how the theory and practice is different in this case.:4:
2) Please note the reference in the the referenced page that it DOES apply to car tires.:4:
I'm not twisting at all. Sure, we're both stubborn, but it takes one to know one. :D
1) I'm no physicist and don't play one on TV. However, airplane tires are not that similar to car tires. They are quite rounded and very heavy plied to handle the weight of primarily impact--which is the time at which the possibility of hydroplaning could be catastrophic. Significantly lower pressure in this situation would result in MUCH more surface area than higher pressures due to the large weight at landing time.
Since runways are smooth, dynamic hydroplaning would not be as likely as on a bumpy road with dips and bumps. Bumps or rises are one area where even a surefooted car can dynamically hydroplane easier due to decreased weight (more upward momentum).
2) the formula does apply to car tires, but only in a theoretical sense. they admit, that the theory is not realistic on that page.
Basically, the message they try to impart has mostly to do with driving as slow as possible in poor coniditions. |
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| N_Jay |
quote:
Originally posted by klinger
Will i really get better mileage going from 32 psi to 35. In turn will i damage the tires. I rotate every 6000 miles.
Thanks for any info
Yes you will get better mileage, and no you won't damage your tires (unless you bought really cheap ones with a sidewall rating less than 35 PSI.) |
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| N_Jay |
quote:
Originally posted by mmmmark
I'm not twisting at all. Sure, we're both stubborn, but it takes one to know one. :D
1) I'm no physicist and don't play one on TV. However, airplane tires are not that similar to car tires. They are quite rounded and very heavy plied to handle the weight of primarily impact--which is the time at which the possibility of hydroplaning could be catastrophic. Significantly lower pressure in this situation would result in MUCH more surface area than higher pressures due to the large weight at landing time.
Since runways are smooth, dynamic hydroplaning would not be as likely as on a bumpy road with dips and bumps. Bumps or rises are one area where even a surefooted car can dynamically hydroplane easier due to decreased weight (more upward momentum).
2) the formula does apply to car tires, but only in a theoretical sense. they admit, that the theory is not realistic on that page.
Basically, the message they try to impart has mostly to do with driving as slow as possible in poor coniditions.
Nothing your wrote even starts to explain how a tire with higher pressure could hydroplane worse then one with lower pressure. |
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| macphanatic |
Runways are typically grooved to provide better traction.
I can't follow any logic that tires that have higher inflation pressures are more prone to hydroplane. The higher the inflation pressure, the smaller the contact patch. Assuming that the weight transferred from the vehicle remains constant, the weight applied to the contact patch remains the same. Therefore, the force in pounds per square inch goes up (same weight over a smaller area). This would reduce the likelihood of hydroplaning.
The higher pressures could result in reduced braking (longer braking distances). Same coefficient of friction between the tire and road and smaller contact area. Therefore reduced braking capacity and longer stopping distance. The actual effect may not be significant if the contact area is not significantly reduced ( a relative term). |
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| mmmmark |
quote:
Originally posted by N_Jay
Nothing your wrote even starts to explain how a tire with higher pressure could hydroplane worse then one with lower pressure.
Read your own link about dynamic hydroplaning. That is much more likely to happen because the tires when over inflated are more prone to "bounce" concussively creating possibility for hydroplaning.
Combined with comfort, these are the two advantages over bias-ply tires and why radials are so widely used. |
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| andyschneider |
06 Pilot LX 4WD - Michelin LTX M/S 107S - 36psi front and rear stone cold - tire wear across the board of 2/32" in 14k miles - still measuring 11/32" inside/middle/outside. On rainy roads like today sticks like glue. No bounce, no cupping - wear smooth as a baby's behind.
I always crank the PSI between 2-4 per tire above Honda's recommendations - ride isn't any harsher, tires wear better, and MPG's are better.
andy |
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| N_Jay |
quote:
Originally posted by mmmmark
Read your own link about dynamic hydroplaning. That is much more likely to happen because the tires when over inflated are more prone to "bounce" concussively creating possibility for hydroplaning.
Combined with comfort, these are the two advantages over bias-ply tires and why radials are so widely used.
Just found this on the tire rack web site.
TIRE PRESSURES IN THE RAIN
For both autocross and road racing, increase tire pressures 6-10 psi from what you would normally run in dry conditions. Hydroplaning occurs when a wedge of water develops between the tire and road surface. This wedge can actually lift the tire off the road and eliminate traction. Increasing the pressure rounds the profile of the tire by decreasing the deflection of the tire. This results in a smaller contact patch - narrower and shorter. It also helps keep the grooves in the tread open so they can channel the water out from under the tire.
http://www.tirerack.com/tires/tiret...e.jsp?techid=58 |
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| klinger |
quote:
Originally posted by macphanatic
I'm thinking of inflating my tires a few more psi for handling/fuel economy purposes. Anyone else doing this?
I see you have a odyssey. I have a 2005 exl pilot as well.Do you reccomend a odyssey, i drive 35000 miles per year. I am compring it to a sienna. The data i have gathered suggest that the sienna gets better mileage. and is 2000 dollars cheaper. I am comparing 2007 odyssey ex to 2008 toyota sienna le . Thanks for any imput. |
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