2017 fuel economy

[dblgoat]

From the Kumho website: "Air Pressure
What should I inflate my new tires to?

Air pressure for your new Kumho tire should be set in accordance with the vehicle manufacturer's specification if it's the same as the size originally equipped on your vehicle. The vehicle manufacturer's recommendation can usually be found in the owner's manual, on the door jamb or in the glove compartment."

From the Michelin website:

"Where can I find the recommended pressure for my tires?

In the vehicle owner's manual.
On a sticker on the driver's door or the gas tank door.
Do not use the number on your tire’s sidewall, as this does not indicate the pressure needed in your tire."

Bridgestone: "Always keep the vehicle manufacturer’s recommended inflation pressure in your tires, including the spare."

Continental: "The correct tire pressure can be found in the following places:

in the car's owner manual
gas tank lid
driver's side door's edge
door post

The air pressure listed on the side of your tire is NOT the correct air pressure for your vehicle. That number is the maximum air pressure for the tire"

 

[ALafya]

http://blog.tirerack.com/blog/coope...bout-the-best-tire-pressure-for-their-vehicle

Most, if not all, modern vehicles come equipped with a placard located on the door jamb showing the vehicle's weight and the proper tire inflation, as well as other useful information. As long as the tire size you are running on your vehicle is compatible with the original equipment tire size, you should always obey the recommended tire pressure -- even if you are increasing or decreasing tire size. Finally, when checking and adjusting tire inflation pressures, the "right" inflation pressures are those provided by the vehicle manufacturer, not the maximum inflation pressure branded on the tire's sidewall. The vehicle manufacturer's pressure recommendation can be found on the vehicle's tire information placard label, as well as in the vehicle owner's manual.

 

[yrwei52]

I run 36psi cold and my tires look beautiful with 22k miles on them so far. 17" rims.

So you're running 2 psi above factory recommended tire pressure and getting the best handling and even tread wear! That proves again running 2~3 psi higher tire pressure than factory spec is a good practice in most cases like many people in this community have found out!

Had I use the factory recommended tire pressure at 26 psi on my 1998 Honda CR-V, it would feel severe under-inflated on these new-generation tires with 51 psi maximum inflation pressure! After many trial errors, the best tire pressure is 36 psi which is way higher than factory spec which was set during P-Metric era with maximum inflation pressure merely at 35 psi.

The maximum load for a tire is rated at the maximum inflation pressure. Unfortunately we still have many tires carry lower maximum inflation pressure at 44 psi instead of 51 psi. So we have to adjust the tire pressure accordingly for best performance and even wear based on maximum inflation pressure for different tires even if they're the same size wither the same load index.

 

[yrwei52]

Everywhere I read about this on the web, it says to use the recommended pressure on the driver side door ...
Do you know something different? Why second guess the recommendation made by Mazda (unless you really put more load on the vehicle)?

So tell me how do I follow those different tire pressure recommendations on my 2001.5 VW Passat? I'd have to constantly adjust tire pressure for different speed and load conditions that would be really bothersome! BTW the tire pressure recommendation placard is on the fuel filler door.

I have to make adjustment and add much more tire pressure than Honda recommended tire pressure on my 1998 CR-V from 26 psi to 36 psi not by second guess, but by my common sense, my feeling of how it drives and the fact of how the tires wear!

 

[Unobtanium]

Where is that "correct recommended tire pressure" documentation found?

IF you answer (door jamb), you are incorrect.

Since that only applies to the OEM factory tire. Once you change that tire, everything changes, even if you keep the same size tire. Each manufacturer has its own specs and recommendations. Many people fail to understand that the door jamb tag only applies to the original factory installed tires.

It can vary some due to tire construction, yes, perhaps, but not enough to warrant trying to second-guess it...who's to say you're not going the WRONG direction? And if it DOES vary, I bet it's VERY little. The way I always found it was by laying 2 strips of rubber on the pavement and then adjusting tire pressure until the contact patch was even. In a CX-5, that's not going to happen, but I did find that the happy zone was usually within a couple psi of the door-jamb recommendation, and probably within the range of error of my pressure gauge.

http://www.wheels.ca/news/over-inflated-tires-are-a-bad-idea/

I have canvassed all the major tire companies and not one was willing to recommend deviating from what the vehicle manufacturer’s placard recommends.

Michelin, in particular, noted, “Michelin’s recommendation is, and always has been, that the correct and only inflation pressure for your vehicle is that which is specified by the OE vehicle manufacturer, either on the placard (inside the driver’s door jamb) or owner’s manual.”

Jon Bellissimo, Goodyear’s director of consumer tire technology, states, “On wet surfaces, lower inflation pressure generally produces slightly higher braking traction €“ until the onset of hydroplaning.”

On the lateral-grip (how well the car holds in the corner) aspect of overinflation, Bellissimo concludes,

“If pressures are increased without the corresponding increase in load (adding weight), lateral grip will generally decrease. For vehicles in the market place, the placard inflation generally provides optimum handling.”

Here we have multiple people who do this for a living. I do not know as much as they do about their own products, and do not feel qualified to deviate from their recommendation except in cases like the aforementioned 26psi CRV and Explorer, which are aberrations, which the CX-5, is not.

If you want to lend weight to your arguments at this point, I feel you are going to have to post concrete data of statistical significance, or reveal yourself as a professional member of the tire/automotive industry in some capacity or something of the sort.

Because your recommendations, if followed, could cause others to be put at serious risk:

The Michelin engineering team ran a computer simulation on a family car with pressures increased to 44 psi from the proper 35 psi.

They report, “Increasing inflation pressure can negatively affect performances such as handling, wear life, worn appearance and braking traction. For instance, our modeling simulations predict, with an increase from 35 to 44 psi, up to 6-per-cent degradation in stopping distance can occur on wet/dry surfaces.”

 

[Unobtanium]

So you're running 2 psi above factory recommended tire pressure and getting the best handling and even tread wear! That proves again running 2~3 psi higher tire pressure than factory spec is a good practice in most cases like many people in this community have found out!
Honestly, I do it because when it gets cold, I'll only be 1-3psi below recommended, rather than 3+. It's not THAT sensitive an issue, but 3+ begins to matter I'm guessing. In my Z06, things changed radically when I got over 5psi above recommended. The car got very twitchy. They delivered it with something like 37-38psi in the tires, and it handled poorly compared to when I deflated them to the correct pressure.

Had I use the factory recommended tire pressure at 26 psi on my 1998 Honda CR-V, it would feel severe under-inflated on these new-generation tires with 51 psi maximum inflation pressure! After many trial errors, the best tire pressure is 36 psi which is way higher than factory spec which was set during P-Metric era with maximum inflation pressure merely at 35 psi. That is absolutely absurd. I think Honda had a "Ford Exploder" moment, and would not use this absurdity as a "norm". I am surprised Honda escaped Ford's fate.

The maximum load for a tire is rated at the maximum inflation pressure. Unfortunately we still have many tires carry lower maximum inflation pressure at 44 psi instead of 51 psi. So we have to adjust the tire pressure accordingly for best performance and even wear based on maximum inflation pressure for different tires even if they're the same size wither the same load index.

Maximum load, yes. Not maximum performance in every-day situations.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=1&

As to people who drive at high speeds...the CX-5 typically will NEVER need adjustment for this...it's maximum speed is warranting a 3psi increase, supposedly, lol
http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=72

 

[yrwei52]

Maximum load, yes. Not maximum performance in every-day situations.

We don't pump up our tires to maximum inflation pressur for maximum load the tires can carry on our cars. Each tire of our CX-5 needs to carry about 900 lbs of load or more. Mazda recommends 34 psi on OEM Yokohama Geolandar G91A 17" tires with 44 psi maximum inflation pressure and 1764 lbs maximum load with 100 load index, and 36 psi for OEM Toyo A23 19" tire with 51 psi maximum inflation pressure and 1709 lbs maximum load with 99 load index. So finding the optimal tire pressure is really a guess work and requires many trials to verify as each tires is different on specs. From many people's experience, adding a couple of more pounds of air above recommended pressure can make CX-5 performs better and the tires can wear more evenly too, not to mention it can have a tiny bit better fuel economy. This can also prevent too much off on tire pressure when there's a sudden temperature drop.

Honda is not the only auto maker who specified 20 something recommended tire pressure in 90's. Everyone had it due to the maximum inflation pressure on most tires at that time could only be at 32 or 35 psi (P-Metric standard).

 

[Lbear]

From the Michelin website:

"Where can I find the recommended pressure for my tires?

In the vehicle owner's manual.
On a sticker on the driver's door or the gas tank door.
Do not use the number on your tire’s sidewall, as this does not indicate the pressure needed in your tire."

Bridgestone: "Always keep the vehicle manufacturer’s recommended inflation pressure in your tires, including the spare."

The air pressure listed on the side of your tire is NOT the correct air pressure for your vehicle. That number is the maximum air pressure for the tire"

I never said that the tire pressure is listed on the side of the tire.

This isn't rocket science. You can quote all the "legal speak" you found online. All tire manufacturers will say "refer to the sticker on the vehicle..." blah, blah, blah

The sticker ONLY applies to the OEM tires and if you REPLACE the OEM tires with different tires, then the sticker on the side of the door or gas tank is WORTHLESS. Take it off and stick it under your birdcage.

Some tires have a max PSI of 35PSI and others have a max PSI of 51PSI. What matters is vehicle load, tire type, usage, etc.

So PLEASE stop quoting me the stupid OEM speak and the legal lingo that all tire manufacturers state. This ONLY applies to OEM tires. Once you change the OEM tire to a different brand/make/model, etc,. then everything changes.

 

[Unobtanium]

I never said that the tire pressure is listed on the side of the tire.

This isn't rocket science. You can quote all the "legal speak" you found online. All tire manufacturers will say "refer to the sticker on the vehicle..." blah, blah, blah

The sticker ONLY applies to the OEM tires and if you REPLACE the OEM tires with different tires, then the sticker on the side of the door or gas tank is WORTHLESS. Take it off and stick it under your birdcage.

Some tires have a max PSI of 35PSI and others have a max PSI of 51PSI. What matters is vehicle load, tire type, usage, etc.

So PLEASE stop quoting me the stupid OEM speak and the legal lingo that all tire manufacturers state. This ONLY applies to OEM tires. Once you change the OEM tire to a different brand/make/model, etc,. then everything changes.

Please consider that there is only a 2psi difference between 17" Yokohama's, and 19" Toyo's, regarding OEM. Different rim sizes, different tire sizes, different brands...and only 2psi difference. Coincidence? I doubt it. I think that the window is rather much more narrow than you are trying to claim, regarding optimal pressures, unless you feel that the tires you are using are VASTLY different from the OEM tire, moreso than if you'd swapped rim sizes and all that. I just don't see how you've found such an outlier of a tire.

 

[dblgoat]

I
The sticker ONLY applies to the OEM tires and if you REPLACE the OEM tires with different tires, then the sticker on the side of the door or gas tank is WORTHLESS. Take it off and stick it under your birdcage.

So PLEASE stop quoting me the stupid OEM speak and the legal lingo that all tire manufacturers state. This ONLY applies to OEM tires. Once you change the OEM tire to a different brand/make/model, etc,. then everything changes.

Please provide a link or information that verifies your statements. Only trying to get the correct information.

 

[madar]

It can vary some due to tire construction, yes, perhaps, but not enough to warrant trying to second-guess it...who's to say you're not going the WRONG direction? And if it DOES vary, I bet it's VERY little. The way I always found it was by laying 2 strips of rubber on the pavement and then adjusting tire pressure until the contact patch was even. In a CX-5, that's not going to happen, but I did find that the happy zone was usually within a couple psi of the door-jamb recommendation, and probably within the range of error of my pressure gauge.

http://www.wheels.ca/news/over-inflated-tires-are-a-bad-idea/




Here we have multiple people who do this for a living. I do not know as much as they do about their own products, and do not feel qualified to deviate from their recommendation except in cases like the aforementioned 26psi CRV and Explorer, which are aberrations, which the CX-5, is not.

If you want to lend weight to your arguments at this point, I feel you are going to have to post concrete data of statistical significance, or reveal yourself as a professional member of the tire/automotive industry in some capacity or something of the sort.

Because your recommendations, if followed, could cause others to be put at serious risk:

Lol, a tire tread depth gauge would be a little more accurate, but whatever works...

 

[ALafya]

Please provide a link or information that verifies your statements. Only trying to get the correct information.

Same thing. Trying to find correct information!

As long as the tire size you are running on your vehicle is compatible with the original equipment tire size, you should always obey the recommended tire pressure -- even if you are increasing or decreasing tire size.

See this post.

 

[mazdadude]

So tell me how do I follow those different tire pressure recommendations on my 2001.5 VW Passat? I'd have to constantly adjust tire pressure for different speed and load conditions that would be really bothersome! BTW the tire pressure recommendation placard is on the fuel filler door.

I have to make adjustment and add much more tire pressure than Honda recommended tire pressure on my 1998 CR-V from 26 psi to 36 psi not by second guess, but by my common sense, my feeling of how it drives and the fact of how the tires wear!

This PIC of the VW Tire Label shows that for 3 different tires and tire sizes the manufacturer is recommending the same pressures.... for the same load rating of tire.

It is a confusing label to say the least, but once you understand it, you can see what is most important...

For the Mazda CX-5, I believe that the difference in recommended tire pressures between the 17, and 19 inch sizes comes from the difference in the Speed / LOAD RATING between the two oem sizes. 100H for the 17", and 99V for the 19".

 

[Unobtanium]

Lol, a tire tread depth gauge would be a little more accurate, but whatever works...

Can you explain how?

 

[yrwei52]

This PIC of the VW Tire Label shows that for 3 different tires and tire sizes the manufacturer is recommending the same pressures.... for the same load rating of tire.

It is a confusing label to say the least, but once you understand it, you can see what is most important...

For the Mazda CX-5, I believe that the difference in recommended tire pressures between the 17, and 19 inch sizes comes from the difference in the Speed / LOAD RATING between the two oem sizes. 100H for the 17", and 99V for the 19".

"For the Mazda CX-5, I believe that the difference in recommended tire pressures between the 17, and 19 inch sizes comes from the difference in the Speed / LOAD RATING between the two oem sizes. 100H for the 17", and 99V for the 19"."
Not much for speed rating, but has everything to do with the difference between maximum inflation pressure, 44 psi on 17", 51 psi on 19"; as their load indexes are very close, 100 on 17" and 99 on 19".

For these two OEM tires, using the same tire pressure at 34 psi to carry the same load will result under-inflated 19" tires. 19" OEM Toyo tire needs more air pressure than 17" OEM Yoko tire to carry the same load for the similar ground patch contact, the best tire performance, and even wear. Because maximum load on a tire is always at its maximum inflation pressure, and its load carrying capacity at lower inflation pressures is proportional to how much inflation pressure is used.

from TireRack:

"Additionally, while a tire's maximum load is the most weight the tire is designed to carry, its load carrying capacity at lower inflation pressures is proportional to how much inflation pressure is used. For example, P235/75R15 P-metric sized, standard load (SL) and extra load (XL) tires used on cars would be rated to carry the following loads at the inflation pressures indicated:"

Air Pressure (psi)	20	23	26	29	32	35	38	41
P235/75R15 SL	1543	1635	1753	1852	1940	2028
P235/75R15 XL	1543	1635	1753	1852	1940	2028	2105	2183

its load carrying capacity at lower inflation pressures is proportional to how much inflation pressure is used.
information

Notice that these two old "P-Metric" tires would carry different load index in specification on newer tire standard. This table merely demonstrates why our 19" Toyo tire with 51 psi MIP needs more inflation pressure than our 17" Yoko tire with 44 psi MIP to carry the same load.

 

[Lbear]

"Additionally, while a tire's maximum load is the most weight the tire is designed to carry, its load carrying capacity at lower inflation pressures is proportional to how much inflation pressure is used. For example, P235/75R15 P-metric sized, standard load (SL) and extra load (XL) tires used on cars would be rated to carry the following loads at the inflation pressures indicated:"

Air Pressure (psi)	20	23	26	29	32	35	38	41
P235/75R15 SL	1543	1635	1753	1852	1940	2028
P235/75R15 XL	1543	1635	1753	1852	1940	2028	2105	2183

its load carrying capacity at lower inflation pressures is proportional to how much inflation pressure is used.
information

Notice that these two old "P-Metric" tires would carry different load index in specification on newer tire standard. This table merely demonstrates why our 19" Toyo tire with 51 psi MIP needs more inflation pressure than our 17" Yoko tire with 44 psi MIP to carry the same load.

Exactly, thank you.

 

[CSI007]

We went on our first long road trip with the CX-5. Outstanding performance and MPG. 4 hours in 95f heat we got just under 34mpg and that was being stuck in traffic for about 30 minutes. On the way back we averaged just over 34 mpg. I am SUPER impressed with this vehicle's gas mileage! This is with two adults and 1 teenager in the car. Mostly highway.

 

[Unobtanium]

We went on our first long road trip with the CX-5. Outstanding performance and MPG. 4 hours in 95f heat we got just under 34mpg and that was being stuck in traffic for about 30 minutes. On the way back we averaged just over 34 mpg. I am SUPER impressed with this vehicle's gas mileage! This is with two adults and 1 teenager in the car. Mostly highway.

Typical speed?

 

[CSI007]

Top speeds ranged from 55 to 70mph. I set the cruise at 68 during a few sections of travel. Most of the trip was 60 to 65. During the last 3 hours of driving I challenged my wife to beat my MPG on the remaining drive and she did! I took a couple of pictures of the monitor but I can't seem to figure out a way to upload pictures here. Looks like I will have to host them off-site.

 

[Unobtanium]

Top speeds ranged from 55 to 70mph. I set the cruise at 68 during a few sections of travel. Most of the trip was 60 to 65. During the last 3 hours of driving I challenged my wife to beat my MPG on the remaining drive and she did! I took a couple of pictures of the monitor but I can't seem to figure out a way to upload pictures here. Looks like I will have to host them off-site.

I'll have to do a slow trip for a bit sometime and see how it does.