• If you currently own, previously owned or want to own an Avalanche, we welcome you to become a member today. Membership is FREE, register now!

Certain Mods affect on MPG

D

dms_1981

New Member
Joined
Aug 2, 2004
Messages
6
Location
Houston Texas
I was curious if anybody out there has similar mods as mine that has experienced a dramatic loss in MPG?

I have a 02 Z66 with 5.3L. I put 24" wheels and tires, lowered 2/3", and at the extreme most an extra 500lbs or weight do to the stereo. Everything else is stock.

Now when my truck was stock I was getting about 16 to 16 and a half MPG. Now I'm only getting a little over 12MPG.

I realize the change in diameter of the wheels and ride high would effect it some but this seems a little much.

Anybody else had this problem?
 
If you did not calbrate the speedo after the tire change your numbers are off. If the outside dia. of the tires are not the same as stock then you really cannot figure your mileage correctly.

Butch
 
I seemed to lose about 1 mpg when I put on the 18" wheels and BFG g-Force T/A KDWs. Their diameter is less than 1% different than the original tires, which is probably mostly due to the orginals having 40,000 miles on them. I attribute the loss in mpg due to the new tires being stickier and/or the added width of the tires and offset of the wheels being less aerodynamic.
 
You also have to factor in the rolling mass of the 24's!! You need to use a little more TQ to get those suckers moving... thus a little more on the go pedal which would translate into some used fuel. Plus the weight of the rim and tire itself.. you could have added close to 6 or 700 lbs between the stereo and rim/tire combo.

And as Butch said if you didn't calibrate for the increase in tire height then everything will be off as far as milage goes.
 
Also the speed he is traveling will be off as well. Need to recalibrate, or figure out how fast you are or are not going when the "needle" is pointing to say 65 MPH. Would hate to find out that your actually doing say 70 MPH. Could make a new friend real easy that way.
 
So let me get this straight. If the wheels + tires are "taller" than the stock setup, what would happen if you didn't recalibrate? Would the odometer register more miles than you were actually traveling? If that's the case....its not a good thing :6:

Does anyone know the diameter of stock '02 rims/tires? I only have 20s, but I'm a little troubled now :2:

Thanks,
Gator
 
Gator what size are your tire?? if you are running a 50 series tire then you have nothing to worry about. 50 series tire are a direct match to the factory size.. 31.8" I run 295/50/20's and I have nothing off or recalibrated the 295/50/20's are 31.8 tall.

 
Example, I put 265/75/16 on my '02 and didn't recalibrate so I was doing 63 MPH when the speedo read 60. An extra 30 miles for every 600 or 300 miles for 6000 on the odometer. Since I traded and put them on my '04 after about 2000 miles my odom reading was reading 100 miles less than actual. The size difference from my 265/75/16 to 265/70/17 is negligible. :D
 
bonedog said:
Gator what size are your tire?? if you are running a 50 series tire then you have nothing to worry about. 50 series tire are a direct match to the factory size.. 31.8" I run 295/50/20's and I have nothing off or recalibrated the 295/50/20's are 31.8 tall.
Click to expand...

Gator, you don't have a Z71 right ? Your's might still need to be reset if you have the same diameter wheels as bonedog. :cautious:
 
Two words:

Rolling resistance

That is going to go way up with those 24" tires.
 
Gator2000 said:
Yea, I'm running 50s.....I'm safe ;D

Thanks
Click to expand...

www.1010tires.com

Go to the tire calculator, then on the left side type in your original tire size - right side type in what you are running or want to run. Compare , this will give the details of each tire and show the pic of size difference.

Example: I have 265/70/17's thought hey, I could bump up to 305/55/17 fro a bigger tire!! :0: Not ! :8: ! !the overall dimension was actually samller and shwo the percentage difference how fast or slow you would be calibrating to.

Pretty fun thing if your in to mathcing size of tires.

>:DIt's how I decided to go to 315/60/18's ;D hummmmm, Beefy ! !
 
You must log in or register to reply here.
Back
Top