Does light alloy wheels improve gas mileage?

[sifan]

My 2003 toyota Echo comes with factory 15" steel wheels. I am wondering if the gas mileage can be improved by using aftermarket light alloy wheels. From Tire Rack the lightest one weights only about 10 lbs.

What are the pros and cons by switching from steel whleels to alloy wheels?

 

[Kestas]

You won't save enough to justify the cost of aluminum wheels. Even the Aluminum Association recognizes that it's not worth it.

 

[Steve S]

No! In all honesty for all intents steel is way better .I have aluminum on both my trucks cause that is the way they came.

 

[lindermant]

sifan,

I'm looking into the same thing for my Honda Civic (want to replace the factory 14" steelies with 14" alloys from either an HX or Hybrid Civic). If I can find a pair cheap enough I'll give it a try.

Watch craigslist or maybe a hybrid car forum for a set of Prius alloy wheels - maybe you can find a pair for cheap and then report back to us

 

[surfstar]

If there was no $ difference I don't see why steel would be better.

You won't get a very noticeable difference in MPG, though. More effect would be from different tires - tread pattern, compound, width, all vary enough wihtin the same "size" tire to make a more noticeable difference.

 

[Jim 5]

Light alloy wheels are just for:

 

[Quest]

Bet ya "see" huge difference from changing to low rolling resistance tires than, say, to compare the weight/mass savings between alloy and steel rims.

 

[sifan]

My Echo is still wearing the original factory Bridgstone tires, which have very low rolling resistance. Wouldn't the lighter alloy wheels mounted with the same tires reduce the rotational mass and improve gas mileage?

You guys give me the impression that the alloy wheels have no merits at all except being show pieces. Do the racing cars use alloy wheels?

 

[Quest]

You'll get better unsprung mass with alloy wheels and that's it. Under normal operating conditions (with the same tire types of same rolling resistance), you shall not see any "obvious" fuel economy difference due to almost similar rotational mass.

 

[XS650]

quote:

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Originally posted by Quest:
You'll get better unsprung mass with alloy wheels and that's it. Under normal operating conditions (with the same tire types of same rolling resistance), you shall not see any "obvious" fuel economy difference due to almost similar rotational mass.

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I don't think you always get that. Some of the low tech alloy wheels are pretty heavy so their low grade castings won't fail.

 

[rpn453]

Benefits of lighter aluminum wheels on the street are better looks and better suspension feel. Acceleration, braking, high-g cornering, and fuel economy would all be unnoticeably improved.

On race cars, they're often trying to get the car as light as possible, so lightweight aluminum or magnesium wheels are part of that.

 

[Curious Kid]

Don't aluminum rims also aid in cooling of the brakes - better heat sinks than steel? I could see how this could be of benefit in racing and perhaps towing situations, but otherwise...Looks right. Feels right. BLING!

 

[TooSlick]

In order to accelerate a vehicle, you have to impart an increase in angular momentum to each wheel, which as I recall is: (M)(Omega)(R), where M is the mass of the wheel, Omega is the angular acceleration and R is the radius to the center of mass. This is in addition to accelerating any additional mass up to some linear velocity.

In other words, decreasing the weight of the four wheels by a given mass has more of a positive effect than reducing the weight of a nonrotating component by that same mass.

TS

 

[sifan]

In this case, why do people waste serious money to buy alloy wheel/tire packages for upgrading their cars/trucks if they do not gain any noticeable mechanical benefits? Just another hype or stupidity?

I will stick with what I have now. At least I do not worry they get stolen.

 

[Jim 5]

There are some minimal benefits performance/economy wise.

That being said, in my view there is no better bang for the buck in the aesthetic improvement department than a nice set of alloy rims.

 

[Kestas]

Sifan, that's exactly what the Aluminum Association said... aluminum wheels are mainly for appearance.

I personally try to sway people away from aluminum wheels in SE Michigan because of the roads here. It gets expensive repairing or replacing dented aluminum wheel rims. Steel is much cheaper.

 

[sifan]

Are alloy rims typically stronger than steel ones? Do they get bent more easily the steel ones?

 

[Gurkha]

The point is if you size up say from a 205-70-15 to a 235 or 245 16 tire, the additional weight of the bigger steel rim can be compensated by the lighter same size alloy wheel thereby putting less load on the suspension which was originally designed for the smaller and lighter tire/rim combo.

 

[Kestas]

quote:

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Originally posted by PRND3L:

quote:

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Originally posted by sifan:
Are alloy rims typically stronger than steel ones? Do they get bent more easily the steel ones?

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generally, no and yes.

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For reference, we do curb crash testing of wheel corners at out facility. The guys who run the test were surprised to find the Class 8 truck aluminum rims were stronger than the steel versions. They can run more tests with the aluminum rims before scrapping them.

 

[John Hilmer 2]

quote:

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Originally posted by Quest:
Bet ya "see" huge difference from changing to low rolling resistance tires than, say, to compare the weight/mass savings between alloy and steel rims.

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This is what I was told prior to changing the out the Potenza factory tires on my '03 Echo. Mine were the 175/65-R14's not the optional 15's. I elected to buy Michlen Harmony tires for the improved wet traction due to my winter commute and safety issues.

I was expecting a loss in mileage, but it didn't happen. No difference at all was recorded. I believe that the Harmony isn't a low rolling resistance tire, but I'm not certain. John