Bigger rims and fuel economy?

For those that have put bigger aftermarket rims on without lifting the truck, how much did your fuel economy change?

 

I wouldn't think that getting a larger rim would aid in fuel economy. Unless you go to a shorter in over all height tire. Say going from a 30.6 to 28" tall. Even going to an aluminum rim of less weight I don't see it saving any fuel. Thats just my 2 cents.

 

I realize that. My question is, the people that have gone with bigger aftermarket rims, how much mileage did you lose?

 

Ok sorry I missunderstood. I went from 16" to 17" wheels and from a 30.6" tire to a 33" and my mileage is has droped less than 1mpg.

 

remember the larger tire... say from stock to a 33" you Speedo/Odo will be off by about 7%.
Which means you are actually going 7% faster/farther than the speedo shows.

(I don't think that i lost anything noticable after my lift)

The rim might actualy aide in better milage if it is lighter than the OEM with the same tire size...

hope this helps..

 

WARNING!! Science Lesson

Bigger doesn't necessarily matter. It depends on the wheel's Moment of Inertia(MOI). In rotational motion, the MOI is the analogue to weight for linear motion. Just like the smaller weight requires less force to push it in a straight line , the smaller MOI is requires less torque to set it spinning.

The closer to the center of the wheel that the weight is concentrated, the lower your MOI and vice versa. You can in theory have a bigger wheel with a lower MOI than a smaller wheel of the same weight. Lighter materials, the design of the wheel, and the tire all affect the total MOI your engine has to deal with.

In very general terms, increasing total tire radius will negatively affect fuel economy. Increasing wheel size and keeping tire size the same depends on the change in weight distribution and is very hard to determine without MOI numbers.

 

Agreed. Which is why I threw Not to mention, wheels meant for trucks aren't exactly known for their low MOI road racing qualities. You are either going for strength to handle off-road environments or a whole bunch of bling.