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a recently put 17" RH evoultion z5000 on my 2k2 civic. seems to me like i make more trips to the gas station now. and also seems like my milage is going up more. is this possible or am i just seeing thing??

 
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your not seeing things, same deal with me. mileage tends to run up a little faster and gas seems to disappear, not to mentioin speedometer will be a little off. i got pulled over and had my cruise set exactly at 75, he clocked me at 78. so i pulled the ole "so can i have a look at your radar?" trick, so he did, and sho nuff, he was right. but i still love the rims. i'll just deal with it

 
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i think you guys are just off driving your cars more so you can show off your rims[IMG]i/expressions/face-icon-small-smile.gif[/IMG] at least i know i do......... more drivin= more gas [IMG]i/expressions/laugh2.gif[/IMG][IMG]i/expressions/laugh2.gif[/IMG]

 
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i just put 17" enkei RS6s. i have had them on for abotu two days. i'll let u know what the end result is.

 
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If you put bigger rims on your cars you will need to set your ECU to take the bigger wheels into account.

 
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> set your ECU

What's an ECU? Electronic Control Unit? Just a guess. With respect to changing rims, I did some investigating into the matter, and 17" rims change will make a difference depending which type of tire you equip it with. It's all about tire/wheel diameter. A nifty program called
Plus Sizing v2.0.2 will allow you to determine which tire and wheel combination will minimize the speedometer difference, which in the end will impact your feul economy.

Obviously, the rim size will be constant since we're looking at 17". But the tire width and aspect ratio can be varied from one tire manufacture to another. The stock P185/65R15 tires on my '02 Civic Si coupe is best matched with P205/45R17 tires, with the overall tire diameter of 24.46" and 24.26", respectively. This accounts to a difference of -0.61 mph when driving 75 mph. Slap on some fatter tires like 225/55's and that changes to a difference of 6.99 mph (you'll see 75 mph on the speedo and be clocked at 81.99 mph).

Cheers,

 
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> What the? That doesn't make sense..... Does it? I thought in moving to a fatter tire, from 205 to 225 as an example, you're just increasing the fatness (width) of the tire, and nothing else.............

With regards to "fatter", I was referring to the aspect ratio, not the width (although I did increase the width from 205 to 225 in the example). Therefore, a 45 to 55 will give you an increase of 6.99 mph when speedo shows 75 mph.

But look at the numbers @ 75 mph:

OEM, New Rim/Tire 1, New Rim/Tire 2, New Rim/Tire 3,
P185/65R15, P205/45R17, P205/55R17, P225/55R17,
Tire Width, 7.28, 8.07, 8.07, 8.86,
Sidewall Hieght, 4.73, 3.63, 4.44, 4.87,
Tire Diameter, 24.46, 24.26, 25.88, 26.74,
Tire Circum, 76.8, 76.18, 81.26, 83.96,
Rev per mile, 825, 831.71, 779.72, 754.65,
Actual Speed, 75 mph, 74.59 mph, 79.36 mph, 81.99 mph,
Difference , 0 (ref), -0.61 mph, 4.36 mph, 6.99 mph,

Between OEM and #1, there is marginal difference in speed. Between #1 and #2 (changing the aspect ratio while maintaining width) will increase the difference by 5.8%. And finally, between #2 and #3 (changing the width, while maintaining aspect ratio), this also increases the difference by 9.3% (with respect to the OEM tires calibration). Understand? The varying factor is the sidewall height, which is a combination of the tire width and aspect ratio. * my apologies that the my chart came out all screwed up *

Nuf Said,

 
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I have 17" Enkei RS6's and I haven't noticed any drastic change in gas except the "cruise just 2 showoff" factor.

 
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WTF? Resetting ECU? your only reset your ECU when the car is not movin... it's ain't got nutthin to do with rims...your not supposed to drive the car when resettting the ECU!!! and the problem might be the tire size. it was recommended that 45's were to be used on 17" somewhere.... bigger overall size means tire revolutions changes ...or it just might be as someone said... now you got rims you drive more...

oh yea... when you reset your ECU it checks the air and fuels ratios and adjust it to the mods you've done to the engine.... got nuthhin' to do with the rims or looks...LOL correct me if i'[m wrong.

AND REMEMBER ALWAYS RESET YOUR ECU AFTER EVERY ENGINE MOD....IT"S IN THE MANUAL....OR ELSE YOU'LL be in BIG troble with the emissions guys and will be seeing the gas station more often[IMG]i/expressions/laugh2.gif[/IMG]

 
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ROTATIONAL AND TRANSLATIONAL MOTION AND FRICTION 101!!!!

17's with 205's re a lot heavyier than 14-15 inch steelies mounted with 185's.

It takes more energy to spin them up, it also takes more energy to translate them (as if the extra weight was sitting in the trunk)

The stickier tires also have a higher friction coefficient...thus more drag

more energy has to come from somewhere (read gasoline)

obviously you have to use more gas per mile thus less MPG...........

if you matched your tires properly the odo will only be off by a smidge....