VX WHEELS How much MPG improvement will they make?
 

Hi,
I have a 1996 civic DX hatchback with 17 inch rims on it at the monent. I am getting an average of 31 mpg with combined highway/city driving...mostly city with the a/c on 95% of the time its hott here in florida.

I just won a set of vx wheels on ebay for $240.00 + 45.00 shipping the wheels are minty and they include the center caps. no curb rash on them.

Wondering how much fuel improvement I should expect when I swap these wheels on with some low rolling resistance tires. Who makes some good LRR tires that will fit the rims?

Thanks!

It's hard to say. Your odometer (and therefore your MPG calculations) probably aren't accurate right now because I doubt you're using a 17" tire size that has the same overal diameter that your stock tire/wheels had. when you change your tire size, it changes the speedometer read out because your speedo is configured with a certain tire diameter.

People don't think of this when they change their wheel and tire size. It will definitely improve, but still remember that most of the benefit will be seen in your driving style.

Your 17inch wheels also weight probably loooot more then the 11lbs (I think) of the Vx wheels. So multiple by 4, its a good weight loss. You also gain on the cost of the tires themself, a significant difference of price between same quality 13inch vs 17inch.

About the MPG bonus itself, I could't tell exaclty.

Remember taht you will have to readjust your mpg readings if the outside diameters of the tires are not exactly the same. Going from 17 to 13 with significantly reduce weight of tire/wheel combo as rims weigh much more than tires. The 13 will weigh lots less overall due to more low-weight tire and less heavy weight rim. Also remember that 13 will prob create less drag as there less rim area for wind to create turbulence. (This can all be canceled in 17 rim with moondiscs though).
All together it should make a diff although it may not be that eaesy to read, especially if your odometer wasnt adjusted for diff sized outside tire diameter, assuming that they were different. I doubt that a 17 rim has a low profile small enough so outside diameter is same as stock 13 inch tire diameter.
Remember that you wont be able to take those 'no brake- momentum saving' turns as fast as you did with the 17s. You will have to slow down just a little for certain turns

You need to crunch the numbers for your specific situation.

To add to what others have said, you'll also gain in fuel efficiency because the tires you put on the VX rims will likely also be narrower than the ones you're running now, so there will be slightly less frontal area (wind resistance) & probably lower rolling resistance.

The VX rims are around 9.x lbs each, if I recall. For the sake of argument, let's say they're 4 lbs lighter than comparable steelies (to change only one variable).

- I've read that reducing rotating mass by 1 lb is equivalent to taking 7 lbs off the car elsewhere. So you're taking off the equivalent of 28 lbs.

- "The EPA says an extra 100 pounds in your vehicle could reduce your miles per gallon by up to 2 percent."

- So in this examle, the VX rims could improve your situation by roughly 0.5%

This should be like the contest where we guessed Sludgy's MPG on his new truck.

I'm guessing 3.7%.

Isn't it true that going up 2+ sizes in wheel size will cut your driving wheel torque? And if this is true, then one will see a decrease in MPG, I would think.

Going to the smaller lighter VX wheels should show a noticable increase in MPG.

Going to a larger outer diameter wheel/tire combo is effectively the same as changing the final drive ratio. It will lower engine RPM at cruise, which will save fuel (within reason - and a tire/wheel change is within reason).

Steel wheel that weighs only 10lbs? What was that on? The steelies on my Mercedes are 15X6 and weigh 14.5 lbs each, and they seem a bit lighter than I remember other steelies being. The wheel/tire combo on my TDI weighs about half the wheel/tire combo on the Benz. The first time I went to rotate the tires on the TDI, I thought the wheel must be made of styrofoam.
The other thing to consider is that less energy is needed to accelerate the wheel up to speed. It's the same reason race guys use lighter flywheels- less energy is shanghai'ed by the acceleration of the rotating assembly, allowing more energy to be applied to the spot where the rubber melts on the asphalt.
I haven't seen anything where anyone has done any driveline component-lightening for the sake of FE, or have I missed the posts? Flyweight flywheels, single thickness disc brakes instead of vented/slotted (to save weight), stuff like that? I mean, lots of hypermilers do stuff like tweak the O2 and MAF sensors, tear out all the seats and upholstery, bring only that one CD they want to listen to, leave the heavy jacket at home, get a nice "high and tight" haircut, all in an effort to eke the last bit of use from every molecule of hydrocarbon (a noble pursuit- my last tank returned 59.8MPG). Did I miss that forum?

Where did you see this? The VX 9.x lb wheels are alloys.

I don't think anyone here has done any extensive driveline lightening for FE.