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Is this normal? 40 PSI on my 19inch wheels + gain MPG

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Old 08-11-08, 01:10 AM
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smokyis350
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Default Is this normal? 40 PSI on my 19inch wheels + gain MPG

Hi, I just purchased new wheels couple weeks ago and installed it. I checked the pressure and the wheel mounting place put it at 40 PSI all around. What is the normal PSI to put on my front and rear wheels? I also noticed a increase of gas mileage after putting my 19s from my stock 18s. Right now I get 20 Average tank mpg for the pass few weeks. I drive the same place everyday. usually I get close to 18-19 MPG.
Old 08-11-08, 01:20 AM
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RTIS250
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Id suggest 33-35psi as normal. The milage could be a fluke. But lighter wheels, and possibly an overall taller set of tires (possibly also due to the higher pressures) can slightly increase milage.
Old 08-11-08, 01:35 AM
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Hartawan
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I am running 245/30/20 - 40 psi, 285/25/20 - 36 psi. Even tire wear.
Old 08-11-08, 01:45 AM
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llamaboiz
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one thing about running a taller rim, you've changed your final drive ratio, bad for off the line but good for high end.
Old 08-11-08, 02:18 AM
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Big Andy
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Increasing tyre pressure will reduce the size of the footprint in contact with the road and will therefore reduce rolling resistance, leading to better mpg. On the negative side though, ride comfort will be reduced and, more importantly, there will be less grip.
Old 08-11-08, 02:27 AM
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I8ABMR
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dude dont trip. I use a 42 psi cold pressure. Its helps innertire wear if the car is slammed and helps prevent wheel dents. I thought it was high intially, but after seeeing how long the tires last I am sold on 42 psi. I run a 30 profile tire I need all the help I can get with dent resistance, and added tire life never killed anyone
Old 08-11-08, 08:26 AM
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combfilter
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Originally Posted by Big Andy
Increasing tyre pressure will reduce the size of the footprint in contact with the road and will therefore reduce rolling resistance, leading to better mpg. On the negative side though, ride comfort will be reduced and, more importantly, there will be less grip.
100% correct.

Yes you can increase your mpg by inflating your tires higher. There is this club of cars (i forget their name) but they are all about seeing how how of mpg they can get doing various things. They have some of their cars hitting 70mpg. like they make sure to drive to where they come to the least amount of stops and crap like that. Over-inflating their tires is another trick they use.
Old 08-11-08, 08:38 AM
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nabbun
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wow 70 mpg? what cars do they drive?
Old 08-11-08, 08:38 AM
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FiveOhNine
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Originally Posted by combfilter
100% correct.

Yes you can increase your mpg by inflating your tires higher. There is this club of cars (i forget their name) but they are all about seeing how how of mpg they can get doing various things. They have some of their cars hitting 70mpg. like they make sure to drive to where they come to the least amount of stops and crap like that. Over-inflating their tires is another trick they use.
hypermilers.
Old 08-11-08, 08:44 AM
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icantsee
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Just like I8ABMR...if I had low profile like 30s, I would run 40 or 42 psi cold.

When my friend had 205/40zr17s on his Integra...he ran 40 psi cold.

You don't want any flex, because you don't want your rims to bend.
Old 08-11-08, 09:59 AM
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sr20mofo
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sorry for the question but what is XX psi cold? nitrious?
Old 08-11-08, 10:23 AM
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4TehNguyen
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the tradeoff with overinflating tires is it reduces your contact patch and reduces your traction. Youre probably driving more careful so you dont ding your new wheels also
Old 08-11-08, 10:59 AM
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Shoganai
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rolling on low profile tires you want to make sure you have good air pressure in the tires to keep from denting your rims... and it will help increase your MPG's
Old 08-11-08, 11:27 AM
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Hartawan
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Originally Posted by sr20****
sorry for the question but what is XX psi cold? nitrious?
Cold means you take the tire pressure reading when your tires are still cold and havent been driven. Once it is driven, the PSI will go up due to friction, which equals heat.
Old 08-11-08, 11:37 AM
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ba-b4
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I also run 40 psi cold on my new lower profile tires. It's pretty much necessary to me because I don't want to dent my new rims. Also if you stick with your older psi range the wider tires I have 10's in back will decrease your mpg due to it having a lot more drag than stock so I can use all the help I can get.


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