How much do lighter wheels affect MPG?

I'm looking at all possible ways to improve the efficiency of my 4 banger. As I've been reading about lighter wheels, there's some discussion of static weight vs rotational weight. If I swap out my stock 16s with some SCS F5s, that will (from what I can gather) translate to a difference of about 320 lbs of rotational weight.

But what I'm looking for is some real world experience. Have any of you switched to some lighter wheels and seen an improvement in MPG as a result? If so, how much?

 

Maybe 1 or 2 mpg. But the price for 4 wheels would take awhile to come ahead.

 

It will take you many, many miles 10's of thousands/years to make up the cost of wheels and tires, what you would save in gas.

 

p=mv

momentum p
mass m
velocity v

assume friction is equal

 

the rotational inertia goes up with the square of the radius. The bigger the wheel, the more of a pain it is to turn. Grossly simplified of course, but important enough that studies have been done on it.

https://www.sae.org/publications/technical-papers/content/2017-01-1533/


@Crobran it depends on how you drive more than anything, but I’d be willing to wager lighter is better around town, but on the highway aerodynamics matter more.

 

Fwiw I ran stock steelies and the oem SR/SR5 tires for ~20k miles and then purchased a set of SR5 take-off alloys (which are lighter than the steel wheels) running with the same Toyota highway tires and noticed no measurable difference in mpg. From my experience tire size and weight makes a sizable difference but switching from steelies to alloys did not.

With the V6 and modifying my driving style (slower acceleration, drifting when possible, highway speeds ~62 mph or less) I can witness a large difference in MPG. I am not sure if the inline 4 benefits in the same way but might be worth trying if you're attempting to stretch mpg.

Check my photo album for a couple >100 mile trips averaging 28 mpg if curious. As soon as the terrain has hills and climbs the mpg will dip WAY down due to our low torque when under 1900 rpm.

 

It is a proven scientific fact that heavy wheels decrease your MPG's by 10 miles per gallon. This is why I have helium wheels, and I get 37MPG's. If you want the link, lemme know!

 

Sorry, I had to

 

Heh, perhaps this is a southern term or a generational thing. Mainly I'm talking about maximizing momentum by paying attention to energy management as opposed to accelerating sideways through a corner.

 

Lighter wheels will come up to speed easier so that will add mpg. Lighter wheels will slow down faster so going downhill or coasting to stops is where lighter wheels will lower mpg. So as mentioned, your driving habits will come into play.

 

Lighter wheels are nice. Lighter tires can be even nicer, assuming you're really going all in.

However, even at the painful prices you'll pay this summer for fuel, you'll take forever to get an ROI if you have to pay retail for the wheels and don't really need new tires already.

Even if someone gives you lighter wheels and you only have to pay swap the tires, it will take a good while just to offset that labor cost.

 

http://hpwizard.com/rotational-inertia.html

“Shaving a pound from your tires is equivalent to shaving at most 2 pounds of non-rotating weight. That's PER TIRE, so a pound off each tire could worth close to 8 pounds of weight reduction. For wheels, the multiplier is closer to 1.6, so saving 5 pounds per wheel (20 total) would feel like a static weight reduction of 32 pounds. For brake discs, it can be as low as 1.2. Regardless of the equivalent weight ratio, you're best off reducing weight as much as possible, as you might expect. For flywheels...you'll have to read the detailed section. Sorry”

Note that aerodynamics are more important during hiway driving. Weight matters more for in-town driving where you are using the brakes a lot. That extra weight requires more braking.

320 lbs seems a bit excessive. Are your current wheels made out of lead? What are the weights of the wheels we are talking about?

 

if its 2mpg difference and if I calculated this right, for every 10 gallons of you would save or lose 1 gallon. So if that's approx 200 miles, you save ~$4 every 200 miles. So if you drive 40,000 miles on the tires, that's a loss or savings of $800.

 

The cost of the wheels will not be offset by the gain in MPG for a pretty long time, but if you buy wheels that you actually want then the gain in MPG is a extra bonus.

 

If you want better mpg…. you need to remove dead weight.

Remove the passenger seat, rear seats, radio and speakers. Remove the whole bed.


But to answer your question about wheels…
I swapped to lighter wheels not because of weight just because I liked the wheel.
I did not notice any difference in my mpg.
But I drive my Taco like ass too! I don’t treat the pedal as if it was egg shells.
I can try to hypermile it this weekend and report back if you wish.

 

My stock wheels are ≈ 25lbs and the lightest FCS wheels were about 18lbs, so it's more like 28 lbs difference. But again, I was citing some numbers (including the 10x rotational inertia) that I'd seen thrown around here and on other forums. Lots of those posts included links to pages talking about all kinds of various calculations that I didn't really want to sort through. What I'm hoping to find is someone who can say "I had X wheels on my taco for a while and then swapped to Y wheels that were 8 lbs lighter and I saw an improvement of Z in MPG." Most of the people talking about this topic, including in response to my original post, are just using guesswork - educated guesswork for sure - but I'm looking for actual experiential numbers.

And maybe I'm trying to find a practical reason to justify spending some $$ on some nice wheels and tires.

 

Your forgot the wife, along with the rest.

 

Let's do some math. An SCS wheel is 22 lb 3 oz. I think.



Steel wheels are, apparently, 32 lbs?

https://www.tacomaworld.com/threads/stock-steel-rim-weight.386463/

I'll make it easier, and say 10lb weight difference per wheel.

That translates to hell if I know, but this thread is showing NO MPG difference....

https://www.tacomaworld.com/threads/milage-difference-with-steel-vs-alloy.407665/
(Side note, I am wondering if the MPG differences could be observed in drive shafts and axles instead?)

BUT let's ASSUME a 2mpg difference, 20 to 22 mpg.
And let's assume 4$ a gallon because

That translates to .01818$/mile savings.

New wheels are....let's say 200 a piece (FYI I can find stock takeoffs for closer to 500/set, just a heads up). That's net 800$. BEST CASE You pay only 800 bucks for the new rims, and you have NO cost in balancing or mounting or TPMS costs, etc. (And a realistic number of 1000$? but I'll use the 800).

This means you will need to drive (a shade under) 44k miles before you break even on the MPG improvements of buying new wheels.

Is it a grand for the rims instead since you're more likely to see that cost for mounting and balancing and TPMS shenanigans too? That translates to a hairy shade under 55k miles to break even on the cost of the new rims.

These numbers also assume you see a TWO MPG difference from buying these wheels, which, as linked above, an anecdotal few people have actually seen no difference.

I think you're more likely to see no difference, and you will see no MPG improvements. You would be better off buying an 800$ corolla 4 banger and driving it until it blows up.

True, but when you get into rotational mass, moments of inertia and all that shenanigans.

https://www.cjponyparts.com/resourc...plies to the,to accelerate than sprung weight.

I only got the google headline from that article so it might be bananaland and make no sense. But, the wheels and tires and axles and driveshafts all matter, and them rotating is not as simple as a 1:1 ratio.

 

My man !!! Buy the wheels for sure!!!!!

Wheels and tires changes the look of our Tacomas drastically!!!

Tell the wife that they are safer for when it rains. Monsoon weather is coming soon so hurry up!!

 

Yes. I was neither implying nor denying the calculations need refinement. I’m hopeful Op saw a pathway to quantitatively make his decision.