45PSI Tires MPG vs. 34PSI Tires MPG
#61
07-19-2008, 09:37 PM
You have some good points - like every thing, technique is key especially in AutoX. A "wider tire" is not going to make one drive better or stick better. A "better" tire will stick better ,meaning a tire made from a better compund.
#62
07-20-2008, 07:37 PM
^^^ I see. I figured you were either running a RSB or had the front disconnected if you were running higher pressure in the fronts rather than the rears.
I don't know that I agree that a FSB is counterproductive. I am running a stiffer FSB in my Fit so I need to loosen off the front end pressures to comphensate. I find it rotates nicely and seems to hold better through the corner than with the stock bar. But you are correct that I am trying to induce some oversteer so I can come in quicker on the corners. I like to leave the rear a bit loose, just preference.
I don't know that I agree that a FSB is counterproductive. I am running a stiffer FSB in my Fit so I need to loosen off the front end pressures to comphensate. I find it rotates nicely and seems to hold better through the corner than with the stock bar. But you are correct that I am trying to induce some oversteer so I can come in quicker on the corners. I like to leave the rear a bit loose, just preference.
The tests run here on our handling pad and track says you are slower with any antisway bar in front and having a rear bar and no front bar was very tricky oversteer. Both FSB and RSB slowest; the Fit tended to lean over just a little bit but the inside tires also lost traction. For maximum cornering speed keep all 4 tires on the ground as long as possible.
#63
07-20-2008, 07:41 PM
Ok, well my fit goes around corners faster with an FSB 
I don't know if your testing takes into consideration spring rates and vehicle height, that may be a factor.
That or my Fit is just a weird anomaly, mine and AJR's
https://www.fitfreak.net/forums/aj-r...ification.html
I don't know if your testing takes into consideration spring rates and vehicle height, that may be a factor.That or my Fit is just a weird anomaly, mine and AJR's
https://www.fitfreak.net/forums/aj-r...ification.html
Last edited by Sugarphreak; 07-20-2008 at 07:51 PM.
#64
07-23-2008, 10:01 PM
Say what you want, but this article did it for me:
Driving Under Pressure: Editorial & Features at Officer.com
I now run my tires at max pressure (44 psi)
My question about the article is that SGT. STORTON recommends the max tire pressure on the sidewall, but is that when the tires are cold of hot? as you drive the temperature of the air increases causing it to of course expand increasing the tire pressure...
Driving Under Pressure: Editorial & Features at Officer.com
I now run my tires at max pressure (44 psi)
My question about the article is that SGT. STORTON recommends the max tire pressure on the sidewall, but is that when the tires are cold of hot? as you drive the temperature of the air increases causing it to of course expand increasing the tire pressure...
#66
07-23-2008, 11:59 PM
Say what you want, but this article did it for me:
Driving Under Pressure: Editorial & Features at Officer.com
I now run my tires at max pressure (44 psi)
My question about the article is that SGT. STORTON recommends the max tire pressure on the sidewall, but is that when the tires are cold of hot? as you drive the temperature of the air increases causing it to of course expand increasing the tire pressure...
Driving Under Pressure: Editorial & Features at Officer.com
I now run my tires at max pressure (44 psi)
My question about the article is that SGT. STORTON recommends the max tire pressure on the sidewall, but is that when the tires are cold of hot? as you drive the temperature of the air increases causing it to of course expand increasing the tire pressure...
Also, what kind of tires are you running that have a max PSI written on them of only 44????? I haven't seen anything that fits out cars for less than 50, just out of curiosity I wouldn't mind knowing.
Also that article is pretty clear that lots (if not all) police agencies do not follow that "max sidewall" pressure and use the recommended or slightly above recommended pressures instead. I would encourage you to contact the Calgary police and see what they do as further proof, I doubt that Transport Canada would endorse this practice on any government vehicles here.
Originally Posted by OFFICER.COM
Many agencies maintain tire pressure at 35 psi since this is what is listed in the owner’s manual and on the door placard.
Last edited by Sugarphreak; 07-24-2008 at 12:05 AM.
#67
08-05-2008, 12:40 AM
I had a chance to try out some different tire pressures today, I started off with 46psi in my tires on the course. With the temps on the track that quickly raised the temps to +52 by the end of my first run.
Basically the results of my first run were pretty disastrous, as I approached the first corner I experienced a sever brake failure due to the tires not grabbing traction and as I entered the corner hot the car plowed unexpectedly. For the rest of the course I experienced terrible traction, there was no positives to report for this pressure.
I bled off my rear tires to 40psi and my front to 44psi, traction improved greatly for my second run and the car was much more controllable and predictable.
For the third run I kept the rear tires at 40psi and the front at 42psi. This is the sweetspot for my official runs, the car handled excellent and I noticed traction was perfect.
For my forth run I reduce the pressure to 38psi in the rear and 40psi in the front. I had similar results to the 3rd run, however I have to say the car felt better for the third run and my timed results confirmed that.
Anyway, just another tidbit of information to add. For me this confirms that there is a delicate threshold for tires which can be as little as a couple of pounds. Where a certain tire's boundaries are is likely to vary based on width, composition and sidewall thickness.
Basically the results of my first run were pretty disastrous, as I approached the first corner I experienced a sever brake failure due to the tires not grabbing traction and as I entered the corner hot the car plowed unexpectedly. For the rest of the course I experienced terrible traction, there was no positives to report for this pressure.
I bled off my rear tires to 40psi and my front to 44psi, traction improved greatly for my second run and the car was much more controllable and predictable.
For the third run I kept the rear tires at 40psi and the front at 42psi. This is the sweetspot for my official runs, the car handled excellent and I noticed traction was perfect.
For my forth run I reduce the pressure to 38psi in the rear and 40psi in the front. I had similar results to the 3rd run, however I have to say the car felt better for the third run and my timed results confirmed that.
Anyway, just another tidbit of information to add. For me this confirms that there is a delicate threshold for tires which can be as little as a couple of pounds. Where a certain tire's boundaries are is likely to vary based on width, composition and sidewall thickness.
#68
08-06-2008, 10:02 PM
I have always rotated and balanced my tires and used the 32psi rule for tires and achieved the manufactures mileage rating. With that said this is the first time I have inflated tires to the Max psig rating and beyond (as of yesterday). The more I read at cleanmpg.com the more I am convinced I need to inflate to 60psi to achieve longer tire life and better mpg. As far as safety is concerned I haven't found anything YET that has proven over inflating compromises safe driving or handling.
Hobbit just posted something rather interesting in this link:
Before you over inflate watch this. - Page 3 - CleanMPG Forums
Hobbit just posted something rather interesting in this link:
Before you over inflate watch this. - Page 3 - CleanMPG Forums
#69
08-07-2008, 07:50 AM
Raising your tire pressues will increase your mpg but it will also wear out the center of your tire tread much quicker than normal. (I've thrown away more than a hundred tires because I inflate them by 10 psi over 'recommended' and the center grooves failed state inspection. My ties, not counting others.) Of course, in my case improved cornering was the object, not mpg. But there was better mpg, too.
Yes, for the Fit I think 50 psi is too much for 19/55x15 tires.
Yes, for the Fit I think 50 psi is too much for 19/55x15 tires.
#70
08-07-2008, 11:26 AM
fityfit -
To each his own. I am rolling at 60psig. Is it for everyone everywhere? NO! I lower my psig when I go on road trips because I am unsure of the condition of the roads and traffic. The higher psig will increase traction and handling to an extent and will increase mpg as well. However, it will cause a more harsh ride, increase your breaking distantce(or decrease your breaking ability) and may make you susceptible to tire punctures. You need to do what you feel comfortable with.
To each his own. I am rolling at 60psig. Is it for everyone everywhere? NO! I lower my psig when I go on road trips because I am unsure of the condition of the roads and traffic. The higher psig will increase traction and handling to an extent and will increase mpg as well. However, it will cause a more harsh ride, increase your breaking distantce(or decrease your breaking ability) and may make you susceptible to tire punctures. You need to do what you feel comfortable with.
#71
08-07-2008, 12:27 PM
fityfit -
To each his own. I am rolling at 60psig. Is it for everyone everywhere? NO! I lower my psig when I go on road trips because I am unsure of the condition of the roads and traffic. The higher psig will increase traction and handling to an extent and will increase mpg as well. However, it will cause a more harsh ride, increase your breaking distantce(or decrease your breaking ability) and may make you susceptible to tire punctures. You need to do what you feel comfortable with.
To each his own. I am rolling at 60psig. Is it for everyone everywhere? NO! I lower my psig when I go on road trips because I am unsure of the condition of the roads and traffic. The higher psig will increase traction and handling to an extent and will increase mpg as well. However, it will cause a more harsh ride, increase your breaking distantce(or decrease your breaking ability) and may make you susceptible to tire punctures. You need to do what you feel comfortable with.
Last edited by mahout; 08-07-2008 at 12:30 PM.
#72
08-07-2008, 12:54 PM
You can believe everything you read on the internet, or you can follow the reccomended 32psi in your Honda manual and information panel located on your driver side door frame.
If you are just after MPG, I just recorded a nearly 44mpg tank using 34psi... so just goes to show that using reccomended pressures will give you good mileage anyway. I also don't turn my car off at any time when I drive
If you are just after MPG, I just recorded a nearly 44mpg tank using 34psi... so just goes to show that using reccomended pressures will give you good mileage anyway. I also don't turn my car off at any time when I drive
#73
08-07-2008, 01:22 PM
Yes, Technique is KEY. It will take more than psig to get better mpg. Increasing the psig was the last thing that I tried for better mpg. However, I am still improving on my other techniques any chance I get.
mahout - No bow or bulge in the center of the tire here. The max side wall pressure is 51psig so 60 is not that far off.
Also, I am not racing or driving fast, thus, the cornering is not that much of a concern for me but I have noticed that the increase pressure has allowed me to stick to the road where as before I would slide.
mahout - No bow or bulge in the center of the tire here. The max side wall pressure is 51psig so 60 is not that far off.
Also, I am not racing or driving fast, thus, the cornering is not that much of a concern for me but I have noticed that the increase pressure has allowed me to stick to the road where as before I would slide.
Last edited by pb and h; 08-07-2008 at 01:24 PM.
#74
08-07-2008, 01:29 PM
Yes, Technique is KEY. It will take more than psig to get better mpg. Increasing the psig was the last thing that I tried for better mpg. However, I am still improving on my other techniques any chance I get.
mahout - No bow or bulge in the center of the tire here. The max side wall pressure is 51psig so 60 is not that far off.
Also, I am not racing or driving fast, thus, the cornering is not that much of a concern for me but I have noticed that the increase pressure has allowed me to stick to the road where as before I would slide.
mahout - No bow or bulge in the center of the tire here. The max side wall pressure is 51psig so 60 is not that far off.
Also, I am not racing or driving fast, thus, the cornering is not that much of a concern for me but I have noticed that the increase pressure has allowed me to stick to the road where as before I would slide.
I posted up my results with different PSI's just as some useful information. If somebody ever pushed their car that hard on public roads I would smack them for being stupid
#75
08-07-2008, 02:54 PM
Wow, I just found this on cleanmpg.com:Before you over inflate watch this. - Page 3 - CleanMPG Forums
But this is what I wanted to share:
After this tank I may increase from 50 to 55 and then to 60 if things turn out good. Yeah, I am willing to take the risk.
But this is what I wanted to share:
After this tank I may increase from 50 to 55 and then to 60 if things turn out good. Yeah, I am willing to take the risk.
#76
08-07-2008, 03:53 PM
mahout - I am not too sure what you are trying to say. The only thing I understand is that you have tires at certain tread depths.
By the way, I have 35K on the stock tires now and no tread wear issues.
By the way, I have 35K on the stock tires now and no tread wear issues.
#77
08-07-2008, 04:12 PM
why do u think that the natural world runs on linear equations? y is usually NOT a lineal function of x!
i.e. if u DOUBLE your velocity u QUADRUPLE drag!!
uneven wear? STOP thinking 2 dimensionally!!!! instead of looking at the tire from a longitudinal direction from the car's perspective (bumper to bumper) and thinking that the tire becomes less square
looking at the tire axially (reading the sidewall perspective) the tire becomes more round with increased pressure while MAINTAINING sidewall squareness
therefore in conclusion-
increasing pressure will-
- REDUCE contact patch when looking at the tire from the side, but will generally stay the same from looking at the tire in a bumper to bumper perspective.
- increase MPG
- reduce braking (increase braking distance)
- increase turning responsiveness
- will increase cornering loads ( how fast u corner) TO A POINT then will decrease cornering loads (at what psi is optimal depends on many many many more variables
the internet is great but, back in the day u had to get info from more reputable sources like text books and magazines and such (accountability is paramount to science), instead of forums where it seems like most people failed and/or didn't take any math and science classes (not to bash forums but most people in general are scientifically illiterate)
i encourage everybody to disregard everything that i and everybody else have written and GO TO A LIBRARY and do some research and get info from reputable educated sources instead of looking into forums where even a six year old can post there "OPINIONS"!!!!!
if u want to get spoon fed chances are u are not gonna get the steak u want but just a mouthful of garbage
give a man a fish and they will eat for a day, teach a man to fish and they will feast for a lifetime.....
i.e. if u DOUBLE your velocity u QUADRUPLE drag!!
uneven wear? STOP thinking 2 dimensionally!!!! instead of looking at the tire from a longitudinal direction from the car's perspective (bumper to bumper) and thinking that the tire becomes less square
looking at the tire axially (reading the sidewall perspective) the tire becomes more round with increased pressure while MAINTAINING sidewall squareness
therefore in conclusion-
increasing pressure will-
- REDUCE contact patch when looking at the tire from the side, but will generally stay the same from looking at the tire in a bumper to bumper perspective.
- increase MPG
- reduce braking (increase braking distance)
- increase turning responsiveness
- will increase cornering loads ( how fast u corner) TO A POINT then will decrease cornering loads (at what psi is optimal depends on many many many more variables
the internet is great but, back in the day u had to get info from more reputable sources like text books and magazines and such (accountability is paramount to science), instead of forums where it seems like most people failed and/or didn't take any math and science classes (not to bash forums but most people in general are scientifically illiterate)
i encourage everybody to disregard everything that i and everybody else have written and GO TO A LIBRARY and do some research and get info from reputable educated sources instead of looking into forums where even a six year old can post there "OPINIONS"!!!!!
if u want to get spoon fed chances are u are not gonna get the steak u want but just a mouthful of garbage
give a man a fish and they will eat for a day, teach a man to fish and they will feast for a lifetime.....
Ok, I have read through this two or three times and I still miss whatever point you are trying to make.
First, you go off about something totally unrelated trying to justify defying basic physics... then you post a bunch of points people on both side of the arguement pretty much agree on anyway... then some kind of rant about how the internet is full of opinions and people should research things for themselves.
Ok, let's get one thing straight. Reduced contact patch is reduced road friction regardless of where the contact is reduced from. Here is where the laws of physics takes over and says it doesn't matter if you are reducing side to side or front to back.
Bottom line is if you have two tire compounds with different contact patches and you put more pressure one one to achieve similar friction amounts it will wear faster. This isn't rocket science!
Reviewing several cases now it looks like the center of the tire is not wearing out as fast as the part just off the center. Looks like tires deflect in a W shape.
#78
08-07-2008, 08:55 PM
If the rim width is wider than the tread width the tread is normally concave to the road so the ttire will need to be inflated more to 'flatten' out the tread on the road and get better handling to boot. That lessens the tendency to wear the tire tread center as much but it still happens from centrifugal force. The faster you drive, especially on corners, the more that happens. That is the reason 195 tires on 6" rims will do better at 10 psi over 'recommended'. However, 20 psi over recommendation is almost sure to wear out the center circumference faster than the outer tread circumference purely because the tread is then quirte 'bowed'. If thats not happening to you you drive a lot slower on curves than I do. Most tires I don't get more than 20,000 miles on the street; only 500 to 800 on track. That includes some Michelins.
Try getting a good tread depth measuring device and check the tread groove depth across your tires at 90 degree intervals around the tire. See if there is a difference between side grooves and center grooves.
cheers.
Last edited by mahout; 08-07-2008 at 09:02 PM.
