Why Big Wheels Are A Bad Idea On Electric Cars - Range Impact!

How Much Does Wheel Size Impact An Electric Car's Driving Range?

Do bigger wheels affect EV range? How much more range will a Tesla Model 3 have with 18" wheels, versus 20" wheels? What about a Tesla Model S, or a Tesla Model X? In this video, we'll analyze how tire width, rolling resistance, and wheel size impact an electric car's range. Personally I was surprised how large the impact is! Especially for highway driving, it's important to know how your wheel size can affect your electric car's range. And with the knowledge learned from this video, is it possible that big wheels alone make up a significant portion of our nation's emissions? Join team big sidewall to see ride comfort, cost, efficiency, and emissions benefits!

Related Links:

Engineering Explained is a participant in the Amazon Influencer Program.

Don't forget to check out my other pages below!

NEW VIDEO EVERY WEDNESDAY!

[crunchyeater]

I am absolutely delighted that Jason has built several videos from one pothole destroying his odd-sized Tesla wheel.

[EngineeringExplained]

**CLARIFICATION!** Why do bigger wheels mean worse efficiency, when the overall tire diameter remains the same? This comes down to aerodynamics. A 20" wheel will cause more of a disruption in airflow than an 18" wheel. That's why Tesla (and others) uses aero covers on their wheels (Car & Driver testing showed it gives about a 3% efficiency bonus at speed). The smaller the wheel, the more of the side profile of the wheel & tire is perfectly flat (the tire is flat, the wheel is open: more tire = more flat area, less open area). Ideally, you'd have just a plain, solid sheet for the wheel, but obviously that's not idea for brake cooling. Wheel covers are today's common compromise as they have some airflow, but minimal.

Let's bring back big sidewalls! Watch till the end to learn how fat sidewalls will save the planet. Car community doing their part. 💪😂

[maschan]

I remember a race car engineer saying the ideal wheel size is the smallest you can fit around your brakes.

[aaronalter]

It's interesting to me that standard wheel sizes have been increasing over the years from all car manufacturers. It seems like it was just for looks, not for ride quality or efficiency.

[yt]

Tire and wheel size has increased substantially in the last 30 years. People may not remember this, but cars like the 1990 Honda Accord LX and the 1989 Camry (base version) had 14 inch wheels and used 185/70R 14 tires. As indicated by the 70 aspect ratio, those cars had wide sidewalls and the ride they provided was fine. When I bought a new car in Sept. of 2017, I bought a 2017 Camry LE rather than the 2018 model (which was already being sold) in part to avoid the new dual clutch automatic transmission, but also to get the smallest possible wheel size (16 inches) and the largest aspect ratio (65) I could. Even the higher priced 2017 Camry models forced you to get larger wheel sizes. An article in a car magazine I read several years ago included an interview with an auto executive who was asked why manufacturers kept on using bigger wheels despite the various engineering drawbacks, and he replied that it was largely done for styling reasons.

[coscorrodrift]

This settles it. I'm calling my crush and telling her that 2 inches less is 15% better, I hope that finally gets her to date me.

[potatocupgaming]

Board: *says 0.6*

EE: "nearly ONE percent!"

[DMSparky]

Big wheels are pretty much worse all around imo. Without watching the video first, tire are usually more expensive, have worse ride quality, more prone to curb rash and bending a rim on a pot hole. Basically worse in the real world.

[rstoner]

I never realized the impact of intentionally going with 16” cheap tire option rather than the 18”. I’m able to get 40.5 mpg average on a 2.0L focus manual. Watching this video really makes me think that tire choice has a much larger impact on mpg than previously thought.

[jmzorko]

Wheel weight also has a lot to do with it (which EE has already made a video about). I had aftermarket 20" wheels (at 35 lbs / wheel) installed on my stealth Model 3 Performance, and my energy usage increased to ~270 wh/m. They looked awesome, but I've been doing a lot of road trips lately and wanted better range. I recently purchased a set of the 19" Tesla sport wheels (at 25 lbs / wheel), and my energy usage is now back to ~240 wh/m - much better :-)

[comickebs]

Hence the reason why the Prius always had tiny wheels - 15". Cheap stuff that was good stuff.

[Dexter_Solid]

Sweet, so my 37" tires on 17" wheels for my truck is really saving the planet. Nice

[rrf]

Me: **Looks in bank affixing grocery cart wheels to car**

[jonathanarmer]

Recently switched from 18 to 19" wheels on my Model 3 and I thought I was going crazy or my battery was just degrading after my range went almost exactly from 299 to 284 and I noticed higher wh/mi when driving so this video provides great clarity and closure haha.

[PenkillerDIY]

Hope you read that. I made allot of calculations for my 3.0 Continental in order to understand how tire pressure is determined. - wanted to use non standard 235/50/19 winter tires and keep rolling resistance, contact patch, etc. to spec. Turned out the required pressure is 2.4 bar - the same as the stock pressure of the stock size 235/50/18 - see why below.
245/40/20 - 2.7 bar cold pressure - ~3.7% sidewall deformation
255/45/19 - 2.3 bar cold pressure ~ 3.8% sidewall deformation
Calculation:
1/2 of axle load is divided by pressure, this gives area of contact patch;
Area/width of tire gives length;
1/2 length of contact patch is used to solve right angle triangle as one side, second side - hypothenuse is the non deformed radius and the third side is the effective radius of the loaded tire. Substract r-eff from r-nominal you get amount of deformation in mm. Find percentage from sidewall height and that's your percentage of deformation.
If you play enough, you'll find out that taller tires allow for less deformation especially if they are tall and wide.
For instance, a 2005 Mustang GT on it's stock 235/55/17 would deform them less than 2% at 2.2-2.4 bar cold.
Allot of info can be drawn from this simple calculation.
And btw, your added air drag calculation is not correct. A wheel has Cd of 1, so your 0.03m2 should be included roughly 4.5 times in the drag of a 0.22 Cd automobile thus contributing to allot more drag than you came with.

Best regards!
P.S. you seem to never react to my comments.

[mihaimera]

So... why does this happen? Why are smaller wheels more efficient? That's what I actually expected you to talk about. The rest of the physics is quite intuitive

[MichaelVanBladel]

"Lets say you have a very slim tyre, 205"

- cries in 175

[TheJube]

Oh yeah!!! I love this video, Never got to liking Low-profile wheels. Yes they react faster but then again, more expensive, louder, stiffer and doesn't protect rim.

[DataCabe]

7:50 Changing tires at 75mph. You, sir, have one hell of a talented pit crew.

[luke]

It would be wonderful if someone did an analysis on various OEM and aftermarket wheels and tires to show how they rank for range efficiency. That way, people could compare them and make informed decisions. Using that along with average tread miles on the tire would be wonderful. This is the kind of stuff I wish Consumer Reports would focus their money on.