I was just wondering if going from the stock 15' to 17'z should effect my gas mileage?...i put on the 350z 17' stock rims and took off my factory tires...It seems that im getting less gass mileage...i have a round trip of 80 miles for work every day and i noticed that my mileage has dropped by about 50 miles since i put on the rims...is this not normal ????


Thanks for any help....

 

only reason you would lose gas mileage if the wheels are heavier than your 15's. i'd imagine that the 17's ARE heavier so that's probably why.

 

does anyone have the exact weight for the following rims/tires:
15 sawblades w/ tires
15 steelies w/ tires
16 se wheels w/ tires

 

well not only are the wheels heavier, but actually they give you a little more power, and usually you won't change your foot habits, and that will use a little more gas too. Happened on my uncle's truck, he went from 17"s to 19"s and noticed a drop.

 

I don't know about the 15", but the 5star 16" are 19.6lbs.

 

If you drive mostly highway, you wont notice a huge difference. But I know that with my SE 17s, the car feels heavier and slower and I get worse mileage around town.

 

biggers wheels give you more power? what are you talking about, that is totally a wrong uninformed comment, please disregard

the 5 star are 19.6 with tires or just rim?

 

weight is only one of the factor

factor #2: rotation energy. 17s takes\ more energy to rotate than 15s, therefore require more power, therefore worse gas mileage
factor #3: the amount of psi per tire. usually you go +2psi from 15s to 17s. but if you choose to have different psi from recommended spec, lower psi will result worse gas mileage (better traction, comfertable ride quality), and higher psi will result better gas mileage (worse traction, uncomfertable ride quality).

 

For all intents and purposes, no.

I recently got 28 mpg on a 440+ mile trip, all highway but with 80 mph bursts. Rims are 18x8 TGF with Sumitomo HTR+ 235/40WR-18, 5 spd 98 SE.

Yes, the rims weigh more. Yes, 235's have more contact with the road than the 215's. Yes, the HTR+ are stickier than the stock RS-A. No, there isn't any discernable difference in mpgs.

 

Thats because its all highway, around town the milage would be worse I believe.

 

I just changed over to my summer wheels last weekend and I noticed a drop in MPG. I had the 15" stock steelies on there for the winter and switched to heavy 18x8 chromes. The car also feels slower especially in the lower rpm's

 

thats noticable since those rims are much heavier and harder to rotate

 

You just changed over last weekend, and you noticed a drop in MPGs already. How many miles have you driven since last weekend? How many gallons of fuel have you consumed? Since my commute is only 28 miles per day, if you wanted to know my mpgs since Sat. you'd have to wait another 2 weeks because I haven't driven far enough to give you an accurate or reliable figure.

 

I could go thru a tank in 3 - 4 days easy. Running appx. 320 miles to the tank around town and some highway.

 

I didnt realize that adding bigger tired and rims would slow down performance, that mean extra modding would need to be done, to compensate for the xtra weight.

kinda discouraging for getting bigger tires and rims. Are there any nice light weight rims out there? or do they not exist?

 

wow, thats a lot of driving

 

Increased weight and rotation inertia can cause a very slight drop in MPG, but the real MPG killer with larger and wider rims is sticky and wider tires (ie drag). There is increased friction and increased wind resistance with wider tires. Even with my 40lb 17" tire/rim combo I see a consistent drop of around 2mpg vs my 43lb 15" sawblade combo.


Dave

 

THanks for all the help guyz...ive definatly seen a drop on my gas miliage since i put on the 17z...and most of my driving is on the highway...ohhwell...the issues does not seem to be to out of the ordinary....so its all good...

THANKS AGAIN FOR ALL THE advice...

 

Definitely just rim....tires are all different!

 

There are lots of lightweight 16's and 17's our there. C5's, SSR C's, Rota,... The list is never ending if your have the cash. My SSR's are just over 14Ibs, 39Ibs Wheel+tire, and have noticed a drop in MPG but there are a lot of other variables effect it such as tuning and driving habits. If you guys are seeing lower highway mileage then that is valid evidence but city driving is way too irratic. There are way to many factors in aftermarket wheels to determine if they will increase or decrease mileage. If you get a 17x8 that magically weighs three pounds you will still have a very large contact patch. Its the combination of weight and contact area. Why are there so many gas mileage threads? This is like the 10th one this month. C'mon guys, get over the fact that its $2 a gallon and you won't be watching the miles so much. Just drive.

I agree that Chickan's statement was very incorrect. I was having a debate about this same subject with my science teacher. He was saying that cars with larger wheels are more economical(Environmental Science course). I laughed in the middle of class when he said this. I contested that if the vehicle is soley highway it would be slightly better for gas but in the city the opposite would be true.

As for the weight. Sawblade is 16.? Ibs. and Brudaddy was correct with the SE.

 

ha ha, just drive...
it does suck to pay over $2/gal....and its also the fact that it went so high so fast. In reality though, $.10 more per gallon is only $1.80 per tank, which lasts me like 2 weeks!

 

motegi traclite weigh in at 10 lbs per rim, $1000 they cost shipped

 

link....waveridr85?
I would like to at least look at those.
Usually, motegi are not that light.
Have they just gone to an all forged wheel or something?
It must be.

 

do any of you happen to know the weight of the 350Z 17' rims. I wonder if they are that much heavier then the stock 15?...i mean im sure they are heavier but is it a huge difference...

thanks again dooods

 

and 19's only weigh 18lbs a piece

 

Those are some good looking rims.
Me Likey!

The stock 17" 350Z are quite a bit heavier than the stock 15's. I am sure of that. Actualy measurements, I am not sure.

 

One thing you guys are forgetting:

If you buy a rim that has a larger rolling diameter than the stock wheels, then your odometer will think you're traveling less distance than you really are, but you're using the same amount of gas.

For example: Instead of going 250 miles on a tank of gas ony our stock wheels, you may only go 200 miles on your larger wheels. You actually WENT 250 but your odometer can't compensate for an increase in rotational diamteres, so it looks like you're getting less MPG.

 

I have a spreadsheet that shows every fill-up I've ever done on my '98 SE. If the mileage suffers with 18's, then I should see the cumulative mpg start to slide downward, starting at 57k when the 18's went on. There are almost 91k miles now. The cumulative mpg is the total miles driven divided by the total gallons consumed. Believe me, 90500 miles is a lot of miles to work with to find the avg. mpg. It never drifted downward, it's exactly the same.

In theory, everybody is right about the 17s, 18s, 19s, 20s being heavier yada yada. The trick in business, and in life, is to correctly apply theory. If you believe that fuel economy can be improved by putting on smaller rims, then do it, saving fuel is a good thing. I think some people are pretty sharp here, they're not disputing overall results, they simply said it could have been achieved by outside factors.

 

http://www.wheelweights.net/

Good side for stock and aftermarket rim weights. Unfortunately the page is a huge PDF file, and there's absolutely no need for it to be a PDF...I never understood that. Guess some car people don't know the first thing about computers/software.

 

That sure is an off-the-wall comment. The PDF is the most common way to share documents. Say you're configuring 2 servers, using a KVM, and need to refer to manuals. One is on 2k Server and the other Enterprise ES 2.1. Since they're servers you're not gonna waste licenses for Office 2k or 2k3 (if it's a .doc, .xls, etc.), so you read your documents put into a PDF, with Reader since it's free. The PDF doesn't care what platform or what software was used to create the document, and its original look is preserved.

 

That is a very good point


Dave

 

I'll clarify:

I love PDF for its universality and WYSIWG format, but HTML is equally cross-platform.... All I'm saying is, why have a PDF file that's half a megabyte when a 10K HTML file would look nearly identical?

It's a question of simplicity (HTML, loads in a second or two) or complexity (PDF, your browser has to load Acrobat in addition to loading the huge PDF file inline). There's no need for PDF for such a simple web table of wheel weights. If the guy had a link to a PDF file that you could download to your hard disk for future reference, that would make sense. But not everyone wants to download it; most just want the ready reference as a bookmarked site, and thus having a PDF as the main page is ridiculous. I can't imagine what the guy is paying in bandwidth on that site!

 

Oh, wow, that must be why my office used to be 14 miles from my home, but after the 18's went on it was 10 miles. DOH!! The really strange thing is I couldn't get to the office any faster even though it was 4 miles closer!

I don't think we are forgetting anything. If we were, the entire +1, +2, +3 concept would be flawed. If you take any tires, and compare the comparable +1 etc. sizes, the outside diameter is the same. 205/65-15, 215/55-16, 235/45-17, 235/40-18, they are all approx 25.4" outside diameter. I would say no matter how many different brands of tires you compare in these 4 sizes, the most they are going to differ by is around 1%. So yes, it's possible, when you're going 137 mph according to the speedo, you're really not going that fast, you could only be going 135.5. That's so negligible it's not even gonna translate to 0.5 mpg. Out of all people on this thread, I think all of them are intelligent enough to choose the correct size, be it 15,16,17, or 18.

 

Yea the people in THIS thread might choose the correct tire sizes, but a lot people don't. Which is unfortunate. I suggest EVERYONE remembers this site: http://miata.net/garage/tirecalc.html