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Anyone know what the weights are for the rims and tires for the various trim level? I do like the 18" but may switch to smaller diameter to reap the mpg and I really like blacked out rims.
 

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The stock 16" wheels are blacked out aluminum (under the hub caps) that some choose to run that way because they like how they look. I doubt you could ever achieve a weight difference that could have a performance effect you could actually notice. You don't take your Niro to the track do you? What you will notice from wheel/tire combination changes will be handling, noise, and comfort. There are a lot of combinations! But you can start by test driving a Niro equipped with the stock 16s and see how you like them.
 

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The 18"ers cost almost 20% in MPG's. Hardly something you would not notice. The larger diameter, width and weight all contribute to the loss.


I'd love to find 18" carbon fiber wheels to offset some of that loss, but the Mega millions is not mine yet! Most I've ever won is a free ticket.
 

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My response about not being able to notice a performance difference was only about a weight difference, not diameter. The OP already made clear that he knows 18" have a mpg hit.
 

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I wonder if the Stock !6 wheel covers ( plastic hub caps ) are for appearance only or for aerodynamics at freeway speeds?
The stock 16 black ones are alloy for light weight. Kia could have made them "look" better very easily? and ditched the wheel covers? Or did they want to market the higher priced models with alloy wheels? $$$$
 

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Feel like I might have a clue why the 18” wheel option loses so much mpg. It has a 1” larger o.d. tire and I tested that for a few days last week on my Niro. I would say the results were about the same and now I want to try a size smaller o.d.to check that effect.
 

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I assume Kia calibrates the odometer for the stock size wheel for the particular trim. So if you change to a different tire size, that could affect the apparent mpg as you cannot recalibrate the speedo. However, the size difference is far smaller than you suggest if you are using the stock tire sizes. Since you are using diameter, it is 3/10 of an inch larger for the 18" tire. I doubt you could tell the impact on mpg.

In a bit of turnaround, actual mpg should increase a little with the larger tire as the final drive ratio is a bit taller. You can see that in the revs per mile figure in the attached comparison. But the drop in rolling resistance overwhelms that small advantage.
 

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Sorry yticolev I was thinking the diff in o.d. Was greater. What I tested was 6% diff in o.d. which gave me l/100 km 5.5 compared to 5 usual.l also took the speedometer diff into account.
 

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Here is a comparison of the 16"ers with just a slightly wider tire.

Tire Size Comparison Calculator
Size 1 205/60 R16 Dia 25.7, width 8.1; Revs 786

Size 2 215/55 R16 Dia 25.3 (11.6%); Width 8.5 (+ 4.9%); Revs 797 (+11), Change in speedo at 60 mph- 59.1 mph

Potential "Benefits" of 55 series over 60 series. A bit quicker acceleration, bigger contact patch (improved handling).
Potential Negatives: Decreased mpg (hard to say how much, would be somewhat dependent on the type of tire & tread), decreased snow traction, slightly lower ride ground clearance / ride height (about 1/4").

While the Michelin Energy AS are not a bad tire, they are middle of the pack when it comes to ride comfort, handling, wet & snow traction (especially important if you live in a snow zone and don't want dedicated winter tires / rims. Both are around $100 for stock size and the Vredestein Quatrac has good fuel economy bona fides.

I'm thinking these are the two t tires for the best all season bang for the buck for the Niro
https://www.tirerack.com/tires/tires.jsp?tireMake=Vredestein&tireModel=Quatrac+5&partnum=06VR6QT5XL&vehicleSearch=true&fromCompare1=yes&autoMake=Kia&autoYear=2019&autoModel=Niro&autoModClar=EX
https://www.tirerack.com/tires/tires.jsp?
message=singleSize&tireMake=Continental&tireModel=TrueContact+Tour&partnum=06HR6TCT&autoMake=Kia&autoYear=2018&autoModel=Niro+Plug-In+Hybrid&autoModClar=EX
 

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If you polish the OEM black painted aluminum wheels, yes, they will be polished alloy.
 

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About 5 pounds per rim or at least in this comparison that's what it was. But that's rotational inertia which has a compounded effect. Pros/cons of the larger rims (which total diameter of the combination of rim/tire stays the same).

Pros:
1. People think they look cool.
2. Better lateral grip. You can turn a faster curve.

Cons:
1. More expensive.
2. Shorter sidewalls cause rougher ride, and in my experience become easily damaged with belts breaking/wheels out of balance/other issues.
3. Also are almost always wider which reduces MPG.
4. Also are almost always wider which causes pour snow performance. Like a crippled duck.
5. Also tend to have performance rubber which is softer which reduces MPG and reduces tread life dramatically. When I had these it was hard to find a tire that would get more than 20,000 miles. They usually wore out or slipped a belt or something stupid way before that though.

I consider it as lesson learned. Two cars like that is enough for one lifetime.
 

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Add to the pros: shorter stopping distance.

Add to the cons: Narrow sidewalls are stiffer which increases rolling resistance, even if same width. Noisier too.
 

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Add to the pros: shorter stopping distance.

Add to the cons: Narrow sidewalls are stiffer which increases rolling resistance, even if same width. Noisier too.
are you sure? Seems the opposite is true. Low rolling resistance train wheels have pretty stiff sidewalls.

Underinflated vs overinflated stiffness vs rolling resistance?
 

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Train wheels do not go over bumps, no need for compliance. No passengers would be able to tolerate solid steel wheels on roads, not to mention the lack of any braking or handling capability on roads. Are you serious, or just trolling?
 

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Train wheels do not go over bumps, no need for compliance. No passengers would be able to tolerate solid steel wheels on roads, not to mention the lack of any braking or handling capability on roads. Are you serious, or just trolling?
of course I'm serious. It is obvious that underinflated tires with less stiff sidewalls have a higher rolling resistance than overinflated tires with stiffer side walls.

Train wheels are the ultimate example of greater sidewall/tread stiffness resulting in lower rolling resistance. The disadvantages of train wheels you mention are true but not relevant to the relationship of sidewall/tread stiffness to rolling resistance.
 
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