How do wheel size and setup affect your range?

[James Anders]

Don't forget unsprung weight, which is weight to overcome inertia. Unsprung weight is far more important for increased range than simply removing weight from the interior of the car (a passenger, carpet, seats for track cars, etc.). I wanted to emphasize range over performance with my MS, so I sold my 21s after getting the car (vin 2379, P85, which at the time came with 21s), and bought aftermarket 19" rims/tires from Tire Rack (OZ wheels, standard 19" size low rolling resistance Bridgestones). The stock 21" turbine wheelset (wheels + tires) weigh around 65 lbs. each! I'm saving almost 10 lbs. of unsprung weight per wheelset. Though I don't have wh/mi data, this HAS to be producing more range, but sacrificing cornering ability, aesthetics, etc. somewhat.

Unsprung weight is that weight that is not supported by the springs/suspension of the car. Think tires, wheels, a-arms, brake rotors, brakes, etc. Excessive unsprung weight will adversely affect handling. Weight of rotating elements, such as tires, wheels and brake rotors not only adds to the regular weight of the car, but as you mention, these things have rotational inertia which must be overcome to accelerate the car. Reducing weight and unsprung weight is a good thing. Reducing weight of rotating elements is extra good.

 

[RonBurgundy?]

Thank you very much for all the responses. I think HankLloydRight said it best. Don't worry about the effect and enjoy.

Very odd thing i found out though, I get lower Wh/mi consumption with my new wheels... they're 20x8.5 and 20x10 rears using Hankook tires. I have the S60 and used to get roughly 308 Wh/mi and over the weekend i got 290 Wh/mi.

I'm assuming that it's because the new wheels are lighter. But thank goodness i get the looks and no decreased range! Also, i may be the first one with 20" Avant Garde M590s!

 

[araxara]

Just a quick datapoint: I was running the stock 21" Turbines with the OEM Continental tires and averaged 291 Wh/mi in 17K miles. I then switched to the 19" Aero wheels with the Michelin Primacy MXM4 tires and now have added 21K miles and was still averaging 291 Wh/mi as of yesterday. Of course the wheel/tire switchover happened right after a software update (don't remember which one) that calculates the Wh/mi differently. Today, I am down to 290 Wh/mi for the first time ever:

 

[R²B]

- Tire wear greatly increases with the size of the tire due to thinner walls i.e. less rubber to wear. I think 19"s get roughly 45K, the 21"s get around 10K

I'd imagine that tire wear (given two sets of tires identical in every way except for size) would favor the larger tire. The larger tire will require fewer revolutions to achieve the same distance as a smaller tire, thereby reducing the total contact required by the larger tire to move the car the same distance.

 

[araxara]

I'd imagine that tire wear (given two sets of tires identical in every way except for size) would favor the larger tire. The larger tire will require fewer revolutions to achieve the same distance as a smaller tire, thereby reducing the total contact required by the larger tire to move the car the same distance.

Yes, but the 19" and 21" tires provided with the Model S have almost identical Revolutions Per Mile. The 21" is a lower profile tire and thus is almost exactly the same diameter as the 19"

 

[R²B]

Yes, but the 19" and 21" tires provided with the Model S have almost identical Revolutions Per Mile. The 21" is a lower profile tire and thus is almost exactly the same diameter as the 19"

Than I agree with you.

 

[RonBurgundy?]

How did you get that picture on your dash! the wheels look odd. Did you customize it somehow? those aren't 21"s or 19"s

Just a quick datapoint: I was running the stock 21" Turbines with the OEM Continental tires and averaged 291 Wh/mi in 17K miles. I then switched to the 19" Aero wheels with the Michelin Primacy MXM4 tires and now have added 21K miles and was still averaging 291 Wh/mi as of yesterday. Of course the wheel/tire switchover happened right after a software update (don't remember which one) that calculates the Wh/mi differently. Today, I am down to 290 Wh/mi for the first time ever:View attachment 57511

 

[jerry33]

How did you get that picture on your dash! the wheels look odd. Did you customize it somehow? those aren't 21"s or 19"s

Those are factory 19" aero wheels.

 

[araxara]

Those are factory 19" aero wheels.

Yes, I had the service center update the picture after they changed the wheels. Unfortunately, this has to be done at the service center right now - or at least that was the case when I had it done.

 

[brianman]

If everything else is equal, 19 > 20 > 21.

I'm confused by this mixture of prose and mathematical expression.

1. [-inf, 19) == (19, ..., 20) == (21, +inf]
2. 19 > 20 > 21

Maybe if someone could plot it for me, that would help.

 

[jerry33]

I'm confused by this mixture of prose and mathematical expression.

1. [-inf, 19) == (19, ..., 20) == (21, +inf]
2. 19 > 20 > 21

Maybe if someone could plot it for me, that would help.

I'm using > as "greater than". (programming sense).

 

[brianman]

I'm using > as "greater than". (programming sense).

Right. And that confuses me. "19 > 20" is "wrong".

 

[jerry33]

Right. And that confuses me. "19 > 20" is "wrong".

Greater tread life and better pothole resistance (not greater nominal rim diameter).

 

[brianman]

Greater tread life and better pothole resistance (not greater nominal rim diameter).

Thus I think you mean...

TreadLife(19" tires) > TreadLife(21" tires)
and
PotholeResistance(19" tires) > PotholeResistance(21" tires)

Quite different from an generic mathematical expression "19 > 21".

 

[jerry33]

Thus I think you mean...

TreadLife(19" tires) > TreadLife(21" tires)
and
PotholeResistance(19" tires) > PotholeResistance(21" tires)

Quite different from an generic mathematical expression "19 > 21".

My assumption, apparently bad, was that it was easy enough to read this particular air. ("Reading the air" means extrapolating what's unsaid from the surrounding context).

 

[tga]

Greater tread life and better pothole resistance (not greater nominal rim diameter).

TreadLife(19" tires) > TreadLife(21" tires)

I don't think this is necessarily true. It is true for the OEM setups, because, as previously pointed out, the PS2's have a much softer tread than the MXM4.

I've never heard anyone make the claim that a smaller wheel/taller sidewall increases tread life for the same tire.

For instance, the Continental ExtremeContact DW is available in both sizes, both with a 340-AA-A rating. I would expect both sizes to wear equally, all other things being equal.

 

[Mayhemm]

Folks -- Tesla provides information in the "top 5 question" section of their website comparing range for 19" and 21" wheels (presumably with the Tesla supplied tires). The site states "Range decreases slightly with larger wheels. 21" wheels have more contact with the road and are made of stickier rubber. Both characteristics increase friction." The Tesla calculator says says that at 70 mph, windows up, AC on, and 70deg outside temp, the 85kWh gets 225 mi with 19" wheels and 215 mi with the 21" -- a 4.4% range loss. The percentage range loss appears to be greater at lower speeds.
Your Questions Answered | Tesla Motors

Damiano, I believe that FAQ is with respect to the 21 inch Continental tire (at least that is what Tesla told me; the standard 21 inch tire was the Continental, although some cars were shipped with PS2 when the Continentals were not available. When the P85+ was released it was fitted with PS2 as standard. The PS2 is sticker than the Continental and thus gets less range. My P85 was originally fitted with the Continental, but was then swapped by Tesla for the PS2 after 900 miles.

Strangely, the Tesla design studio still claims a range increase of 10-20km (6-12 miles) with the P85+ package (Michelin PS2's) over the standard 21" tires. I've never driven the Continentals, but I can't image this is the case as the PS2's are a stickier tire.

 

[jerry33]

Strangely, the Tesla design studio still claims a range increase of 10-20km (6-12 miles) with the P85+ package (Michelin PS2's) over the standard 21" tires. I've never driven the Continentals, but I can't image this is the case as the PS2's are a stickier tire.

They are also newer technology.

 

[fred z]

Ok, major question here...I think this is the place for the answer.
I am receiving my MS in 3 weeks. It will come with 21 in turbines. I am under the impression that they NOW come with Michelin PS2's, 245 all four corners? I know the staggered pkg has same with 265's in rear. Now....I have spoken to my tire pro and I know I can get , with some research and assistance....PSS's in 255 which I was considering front...and 285's in rear. That would look pretty nice...as I had an Equus and did that exact combo but with Yoko's and custom wheels and it looked awesome.
Will this negatively affect the car......distance?...ride........but most of all clearance in the rear with these tires?
Thanks in advance. Plus....If I go that direction I will be selling my 245's, new to whoever is interested.
fred zl

 

[Mayhemm]

They are also newer technology.

Do you really think that could account for it?

Isn't it more likely that Tesla's range claim is just incorrect?