QUESTION 2023 Air Touring Tire efficiency

[xponents]

Play nice, kids. Don't make me turn this car around...

When you don’t want to go on the trip, that’s a good thing… ask me how I know?

 

[Jeanwoodie]

This is not true. The overall circumstance of the tire is approx the same. A larger wheel is fitted with a tire with a shorter sidewall.

Larger wheels are much heavier and the extra rotational mass decreases efficiency.

Also, summer tires are designed to deliver better grip which means more friction with the road surface and less efficiency.

Daniel,
You “nailed” it. Higher rotational moment of inertia for 20 and 21 inch tires.

 

[illopp00]

The circumference of the wheel has almost nothing to do with the reduced range of the 20" and 21" wheel vs. the 19" wheel. The tire circumference is about the same on all the wheels offered by Lucid (the smaller wheels have taller profile tires mounted to them resulting in about the same tire circumference on all three). The impactful differences have more to with wheel width and which tires are installed on each. The 20" and 21" wheels have higher rolling resistance summer tires. Also the 20" and 21" wheels have wider tires mounted to them which is detrimental to aerodynamics.

The 21s are just heavier in general as well, more inertia therefore eneergy used to move them.

 

[Jeanwoodie]

The 21s are just heavier in general as well, more inertia therefore eneergy used to move them.

Agree, given the same radius of gyration the increased mass requires more torque to rotate the ‘disk’ I,E wheels, assuming the radius of gyration is the same distance from the center of rotation (axle). However it is likely the 21” inch wheel sans tire has more mass at a greater distance from the axle which is a squared function requiring disproportionately more torque to rotate and maintain rotational speed.
So both increased weight at a greater distance from center of rotation results in approx 10% loss in vehicle range.

 

[Daniel2022AT]

The tires themselves have significantly different coefficients of friction which impacts efficiency. By definition, sports tires or summer tires have greater grip which means greater friction and less efficiency. I think that is about a 10% difference. Maybe half of that again comes from the mass and geometrical physics. I’m guessing a 15% overall difference in efficiency between the 19’s and 21’s.

 

[Jeanwoodie]

Daniel2022AT
Oops - not per Google:
“Summer tires have lower rolling resistance than winter tires, which can improve handling and efficiency while also reducing noise. However, summer tires are not designed for winter driving conditions and perform poorly on ice and snow.”
So per the above the rolling efficiency of 21” is better than rolling resistance of the 19” M/S option leaving the increased torque to turn the 21” option as about the only rational conclusion for the negative range impact.

 

[HariK]

I drove on the stock 19s in pure awd at temp ranging from 32 to 115 and on light snow 3 inches. No problem at all. I average 3.6 miles per KWh in 17k miles. The tires still look new.

 

[Neurio]

Daniel2022AT
Oops - not per Google:
“Summer tires have lower rolling resistance than winter tires, which can improve handling and efficiency while also reducing noise. However, summer tires are not designed for winter driving conditions and perform poorly on ice and snow.”
So per the above the rolling efficiency of 21” is better than rolling resistance of the 19” M/S option leaving the increased torque to turn the 21” option as about the only rational conclusion for the negative range impact.

The 19s are all seasons, not winter tires. The AS tires have lower rolling resistance than both the summers and winters, as both of those are made with traction in mind.

 

[Jeanwoodie]

The 19s are all seasons, not winter tires. The AS tires have lower rolling resistance than both the summers and winters, as both of those are made with traction in mind.

Ok rephrased the question with same/ similar response:
“Summer tires typically have lower rolling resistance than all-season tires, which can improve fuel economy”

 

[Neurio]

Ok rephrased the question with same/ similar response:
“Summer tires typically have lower rolling resistance than all-season tires, which can improve fuel economy”

You can't believe AI...
From America's Tire regarding summer tires:

However, because of their soft rubber compound, they wear out faster (compared to all-season tires) and increased rolling resistance, making them less energy efficient.

Discount Tire | Tires and Wheels for Sale | Online & In-Person

www.discounttire.com

From Priority Tire regarding all season tires:

These tire sets offer low rolling resistance all year long. Therefore, all season tires guarantee better fuel efficiency.

The decreased rolling resistance manages to minimize the vehicle's fuel consumption and CO2 emissions.

Loading…

www.prioritytire.com

 

[Jeanwoodie]

You can't believe AI...
From America's Tire regarding summer tires:

Discount Tire | Tires and Wheels for Sale | Online & In-Person

www.discounttire.com

From Priority Tire regarding all season tires:

Loading…

www.prioritytire.com

Wow, what a great pitch for All Season tires. That’s been my choice for all my vehicles as I’ve always lived in snow country (currently preferring Michelin CrossClimate 2 for my Subaru Ascent).
So it appears bottom line for all practical purposes is 19 inchers only way to go for both the reduced torque requirement and rolling resistance over 21” summer tires. Unless esthetics and track performance is worth 66 miles of EPA rated range.

 

[Daniel2022AT]

Daniel2022AT
Oops - not per Google:
“Summer tires have lower rolling resistance than winter tires, which can improve handling and efficiency while also reducing noise. However, summer tires are not designed for winter driving conditions and perform poorly on ice and snow.”
So per the above the rolling efficiency of 21” is better than rolling resistance of the 19” M/S option leaving the increased torque to turn the 21” option as about the only rational conclusion for the negative range impact.

Wrong comparison. Summer tires compared to high efficiency all season tires.

 

[ahmadr]

The tires themselves have significantly different coefficients of friction which impacts efficiency. By definition, sports tires or summer tires have greater grip which means greater friction and less efficiency. I think that is about a 10% difference. Maybe half of that again comes from the mass and geometrical physics. I’m guessing a 15% overall difference in efficiency between the 19’s and 21’s.

While there is often a correlation between traction and rolling resistance, especially in wet conditions, they are not the same thing and the rolling resistance certainly does not come from the coefficient of friction