Wheel Size fuel economy?

Joined
Aug 23, 2017
Messages
2
Location
Columbus
Country
Country
#1
out of all the site i look at that discussed the Model 3 wheels, what hasn't been discussed is the fuel economy of the different sizes.

My question is what would the different in fuel economy between the 18 vs 19 inch wheels?
We know for the S and X they shows the range difference you would see between its 2 wheel sizes. But what hasn't been mentioned is the difference between the 18 and the 19 in.

Does the 18in give better range but less grip and rougher ride compare to the 19 in? by what degree? is it just all about looks?
 

SSonnentag

Well-Known Member
Joined
Mar 30, 2017
Messages
324
Location
Peeples Valley, Arizona, USA
Tesla Owner
Model S
Country
Country
#3
In general, the taller the sidewall, the smoother the ride. Short sidewalls give better cornering response as there is less sidewall roll. Taller sidewalls give better hookup for jackrabbit starts.

18" Pros
  1. Should weight slightly less (more range)
  2. Quieter
  3. Less puncture prone
  4. Less chance of wheel damage with potholes (curbs? Hopefully not an issue.)
  5. Better foul weather traction
  6. Aero covers (more range)
  7. Drag racing hookup
  8. Smoother Ride
  9. Cheaper Tires
  10. Longer Wear
  11. $1500 in your bank account
19" Pros
  1. Arguably look better
  2. Improved handling
 
Last edited:

Sandy

One obsession to the next
TOO Supporting Member
Joined
Jun 3, 2017
Messages
960
Location
Ontario east of the GTA
Tesla Owner
Model 3
Country
Country
#7
out of all the site i look at that discussed the Model 3 wheels, what hasn't been discussed is the fuel economy of the different sizes.

My question is what would the different in fuel economy between the 18 vs 19 inch wheels?
We know for the S and X they shows the range difference you would see between its 2 wheel sizes. But what hasn't been mentioned is the difference between the 18 and the 19 in.

Does the 18in give better range but less grip and rougher ride compare to the 19 in? by what degree? is it just all about looks?
This is from 2010 but covers it quite well:

http://www.caranddriver.com/features/effects-of-upsized-wheels-and-tires-tested
 
Joined
Aug 23, 2017
Messages
2
Location
Columbus
Country
Country
#8
I do agree.
I was just wondering if we had any actual numbers yet.

But ~10% more range over the 19in tires is a good number.
But if you get ~10% more range on a 300 mile range car, that ~30 more miles. That makes a BIG different.
 

SSonnentag

Well-Known Member
Joined
Mar 30, 2017
Messages
324
Location
Peeples Valley, Arizona, USA
Tesla Owner
Model S
Country
Country
#9

Sandy

One obsession to the next
TOO Supporting Member
Joined
Jun 3, 2017
Messages
960
Location
Ontario east of the GTA
Tesla Owner
Model 3
Country
Country
#10
I do agree.
I was just wondering if we had any actual numbers yet.

But ~10% more range over the 19in tires is a good number.
But if you get ~10% more range on a 300 mile range car, that ~30 more miles. That makes a BIG different.
This shows 3-4% due to size, so being an aero design on top of that could have a significant impact as well. I'm hopeful that the EPA numbers don't account for aero wheels.
The other thing that hasn't been brought up yet is the tires.

The Michelin's on the 18" are Green X LRR (low rolling resistance) with a 500 AA (500 is tread life and the A A is temperature and traction).

The Conti's Pro Contact on the 19's have a 400 A A rating and an XL rating (extra load) but not so much LRR.

Soooo, Tesla has maximized the tire for the standard battery. The 500 wear index helps it achieve the LRR designation (slightly harder rubber). The aero cover gives the wheel/tire combo the best solution to maximize range. The 19" on the LR battery are still great tires! I have them on my Escape. The XL has more to do with the extra weight due to the battery.
Disclaimer, I'm not an expert. I learned a lot about about wheels, tires and rubber compounds racing motorcycles and open tracking cars on road courses.
 
Last edited:

Thomas Mikl

Well-Known Member
Joined
Jun 26, 2017
Messages
214
Location
Graz, Austria
Country
Country
#12
I totally agree 18'' and Aeros will give you better efficiency.

What I do not understand is how they get 10% better efficiency.
Now of course these Aero covers might have some inherent aerodynamic effect that I cannot see from just looking at them without wind tunnel data. but my gut tells me that 5-6% would be pushing the laws of physics.

Or maybe his comment was generous and he was thinking 5% with covers off and another 3% when you go 19'' wheels, lets tell them 10%?

However the 19'' seem to have a turbine design that could or could not be aerodynamic, so it is even possible that the 19'' has same or better efficiency than the 18'' with covers off, due to better aerodynamics?

God I need more data... hehe
This is a physicists nightmare... speculating without sufficient data...
 

SSonnentag

Well-Known Member
Joined
Mar 30, 2017
Messages
324
Location
Peeples Valley, Arizona, USA
Tesla Owner
Model S
Country
Country
#13
I tend to agree with your hunch, Thomas Mikl, that the 10% number is a rounded up number tossed out there for lack of time or interest by the engineer to go into great detail in explaining the real efficiency benefit breakdown. Smaller, lighter wheels, lower rolling resistence tires, and aero covers all add together. Not likely to come out to exactly 10%, but if the numbers are really 7.34% and you casually throw out a number to a curious bystander, 10% is an easy number to spew.
 

SoFlaModel3

@Teslatunity
Moderator
TOO Supporting Member
Joined
Apr 15, 2017
Messages
9,814
Location
Florida
Tesla Owner
Model 3
Country
Country
#14
In general, the taller the sidewall, the smoother the ride. Short sidewalls give better cornering response as there is less sidewall roll. Taller sidewalls give better hookup for jackrabbit starts.

18" Pros
  1. Should weight slightly less (more range)
  2. Quieter
  3. Less puncture prone
  4. Less chance of wheel damage with potholes (curbs? Hopefully not an issue.)
  5. Better foul weather traction
  6. Aero covers (more range)
  7. Drag racing hookup
  8. Smoother Ride
  9. Cheaper Tires
  10. Longer Wear
  11. $1500 in your bank account
19" Pros
  1. Arguably look better
  2. Improved handling
Is there someone arguing that the 18" aero rims look better than the 19" sport rims? ;)
 

John

Tech Founder
TOO Supporting Member
Joined
Apr 15, 2016
Messages
1,644
Location
California
Tesla Owner
Model 3
Country
Country
#15
Still hoping they offer another 18" alternative. If they offered a wheel that was a shrunken version of the 19" sport version, that would be perfect. I'd trade 5% highway range for that (which you can get back by driving 5 mph slower, probably, when you need it).
 

Michael Russo

MSM Team Founder, Midnight S≡R≡NITY rider
Moderator
TOO Supporting Member
Joined
Oct 15, 2016
Messages
5,802
Location
Pau, France
Tesla Owner
Model S
Country
Country
#16
Still hoping they offer another 18" alternative. If they offered a wheel that was a shrunken version of the 19" sport version, that would be perfect. I'd trade 5% highway range for that (which you can get back by driving 5 mph slower, probably, when you need it).
Me too, yet something tells me a sizeable chunk of those like @SoFlaModel3 and me who can't stomach the UWCs and are thus prepared to fork out the $1,500, would reduce T≡SLA 's margin on the car by close to a grand!! ;). So, unlikely... IMHO...
 
4

4701

Guest
#17
I totally agree 18'' and Aeros will give you better efficiency.

What I do not understand is how they get 10% better efficiency.
Now of course these Aero covers might have some inherent aerodynamic effect that I cannot see from just looking at them without wind tunnel data. but my gut tells me that 5-6% would be pushing the laws of physics.
Yea. I was also surprised on that. So I was thinking for a while.
And "up to" might literally mean up to. We know what happens when we go faster.
And I think it is totally reasonable to believe 10% range gain is at top speed. Also 10%
might also include rubber compound (rolling resistance): 19" likely have softer mix.
In city, there will be hardly a percent of difference*. Mostly due to 18" wheels being very light (they have
actually minimal amount of metal, which is good for economy, no matter caps on or off). Turbine
wheels look really meaty. Which is not good.

AFAIK, both tires have the same width and circumference. This means rolling resistance and drag area is almost same.

*same tire compound
 

JWardell

Legendary Member
Joined
May 9, 2016
Messages
3,721
Location
Boston
Tesla Owner
Model 3
Country
Country
#19
OK... So, a show of hands? Who will be changing their cars over to 16" steel wheels with 195/60R16 tires inflated to 60 psi? Uhm... Hello? HelloooOOOoo? Is this thing on?
I am curious to find out what smaller sizes are possible, for the purpose of getting a set of winter wheels (which perform better in snow with smaller/thinner sizes, not to mention cost much less).
 
4

4701

Guest
#20
Unfortunately it looks like majority of 17" wheels will not fit due to front brake caliper. Maybe some slimmer wheels will. I doubt.
Playing with tire width on 18" might result in small speed reading error. 10mm reduction is not worth the hassle.