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Wheel size and range effect

Wheel size and range effect

I am curious how changing the wheel / tire size effects range. My car came with 18" Aero's but I swapped over to 19" wheels.

I assumed a 10% max loss in range to be on the safe side but I imagine it's not that dramatic. Anyone have 1st hand data or info that shows how the different tire / wheel size effect range?

I thought this was a good article but wanted to get some feedback / info 1st hand from others.

https://cleantechnica.com/2019/10/12/how-tesla-tire-size-impacts-tesla-r...

raqball | December 2, 2019

The table in the above linked article says my SR+ get a 3% reduction with 19"vs 18"... If that's correct then it's really not much at all.. 3% would only = 7.2 miles...

PteRoy | December 2, 2019

Well. For what it’s worth. October 20th 18” aero caps and summer tires 100% charge 249km. As of today, 18” winters with steel rims 259km at 100%.

So. I gained 10km with no aeros and heavier rims and tires?

That’s my input. I don’t know what it means.

GHammer | December 2, 2019

It's going to be difficult to get "real world" difference data due to confounding factors. I (like many others) run both sizes on my 3 but that is to be able to run seasonal tires. I do run OEM's on my 19's but that is only in the summer, On my 18" Aero's I run winter tires in the winter. Different tires, different operating temperatures, cant separate effects of size out.

Bighorn | December 2, 2019

It’s about weight and rubber compound, not diameter. Smaller diameters tend to weigh less but don’t have to.

raqball | December 2, 2019

GHammer | December 2, 2019
It's going to be difficult to get "real world" difference data due to confounding factors. On my 18" Aero's I run winter tires in the winter. Different tires, different operating temperatures, cant separate effects of size out.
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Good points...

If the data in the article is correct then the rage reduction is minor.. I was just curious if anyone had real world info. I didn't track my stats before the swap and I made the swap pretty early in ownership...

lbowroom | December 2, 2019

The biggest factor is rolling resistance. Softer compounds and wider tires have the most effect. Yes, it takes energy to get a heavier wheel rolling, but it also will continue momentum once rolling and give you back at least the regen percentage when stopping. Diameter itself has no effect other than indirectly affecting weight as Bighorn indicated. If you push the offset out toward the edge or the fenders, there is an aero penalty to pay as well.

I'm running 285/35 19 Continental Extreme Contact Sports on a 9.5" rear and 255/40 19 on 8.5 front. I haven't done a range study.

lbowroom | December 2, 2019

But my car is about 1.25" lower on coil overs which helps on aero

Tuning In | December 2, 2019

12% increased consumption from aero covers with MXM4’s vs 19” with Continentals is what the wife’s car saw over 10,000 miles on each set of wheels and tires.

FISHEV | December 2, 2019

When I switch to 18" 245/40/18 I used this calculator to see the effect.

https://tiresize.com/calculator/

calvin940 | December 2, 2019

@FISHEV

Go away, EaglesPDX. Nobody wants you here.

raqball | December 2, 2019

Tuning In | December 2, 2019
12% increased consumption from aero covers with MXM4’s vs 19” with Continentals is what the wife’s car saw over 10,000 miles on each set of wheels and tires.
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Wow 12% is a lot... I wonder how accurate the table in the OP link is.....

Not sure If I've taken much of a hot with the swap but I am interested in finding out how much as I might swap back to 18's if it's a big one.. If 12%, I'd swap back...

lbowroom | December 2, 2019

Pick a low resistance tire and you won’t see a difference

raqball | December 2, 2019

lbowroom | December 2, 2019
Pick a low resistance tire and you won’t see a difference
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I'll keep that in mind when I need new tires. Any tire recommendations for the 19" wheels?

Tuning In | December 2, 2019

The Continentals have the Eco Plus which is their version of a LRR tire. The added wheel weight and the wider cross patch is likely the culprit (yes I do realize they are both 245’s) but the Conti on 19” look noticeably wider than the 18” Michelin’s.

-TheJohn- | December 2, 2019

For those still watching/reading at this point I'd like to inform you that the individual named as fishev in this thread is a super long term infestation troll who has been banned at least once for spreading utterly false and defamatory things about Tesla and for being a liar.

Please Flag and ignore any and every single thing they post. Don't respond if you can avoid it.
Thanks!

beaver | December 2, 2019

@raqball do you have any data you can share since you have used both?

mcmorj | December 3, 2019

I believe the maintenance tab in the driving menu asks you what size wheel you have - so that the range may be more easily predicted. The size of the wheel is a factor in range as it is a direct change to the "gearing" of the final drive. Generally, the smaller the wheel, the slightly better the range. I suppose this would only be a factor if the tyre saze was also altered? Anyway, many car websites quote the variance in MPG based on the size of wheel so it certainly impacts ICE cars.

Bighorn | December 3, 2019

The size of wheel on the reset originally was there for resetting the TPMS and having different PSI specs for the different diameters. Nothing about odometers or gearing since they are all matched circumferences.

raqball | December 3, 2019

beaver | December 2, 2019
@raqball do you have any data you can share since you have used both?
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Sorry I do not which is why I started the thread.. I was not really paying close attention when I had the 18"'s and I only had them for about a month before I changed over to the 19"'s

lbowroom | December 3, 2019

OMG fish, you don’t lose range from diameter changes. That’s just odometer error.

lbowroom | December 3, 2019

Nothing to do with energy used

JAD | December 3, 2019

There are two factors affecting range:

1. Rolling resistance which is a factor of tire compound, tread pattern, aero drag and tire pressure. Softer, sporty tires on rims that cool the brakes will have a lot more resistance than an economy tire on aero rims.

2. Wheel weight, which includes both the tire and the rim. The circumference of all the sizes is about same, but changing rim diameter almost always adds weight as you go bigger. In addition, the smaller tire sidewall means the sidewall needs to be stronger as well, so even the same tire circumference with a smaller sidewall often results in a heavier tire so the tire and wheel combination weight grows even more. The general rule is the wheel/tire unsprung weight is about 4 times as important than normal weight. So if upsizing from an 18" to the 20" increases the weight by a typical 5-10 lbs, you would figure 5-10 lbs times 4 wheels times the factor of 4 or the equivalent of carrying 80-160 lbs.

Combine that with rolling resistance and the total change can be pretty significant. Of course, a lower roll resistant 20" tire on a very light rim would virtually eliminate any penalty compared to an 18".

raqball | December 3, 2019

JAD | December 3, 2019
There are two factors affecting range:

1. Rolling resistance which is a factor of tire compound, tread pattern, aero drag and tire pressure. Softer, sporty tires on rims that cool the brakes will have a lot more resistance than an economy tire on aero rims.

2. Wheel weight, which includes both the tire and the rim. The circumference of all the sizes is about same, but changing rim diameter almost always adds weight as you go bigger. In addition, the smaller tire sidewall means the sidewall needs to be stronger as well, so even the same tire circumference with a smaller sidewall often results in a heavier tire so the tire and wheel combination weight grows even more. The general rule is the wheel/tire unsprung weight is about 4 times as important than normal weight. So if upsizing from an 18" to the 20" increases the weight by a typical 5-10 lbs, you would figure 5-10 lbs times 4 wheels times the factor of 4 or the equivalent of carrying 80-160 lbs.

Combine that with rolling resistance and the total change can be pretty significant. Of course, a lower roll resistant 20" tire on a very light rim would virtually eliminate any penalty compared to an 18".
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Excellent info, thanks!

Bighorn | December 3, 2019

@JAD
Thanks for expanding on my answer

FISHEV | December 3, 2019

"Wheel weight, which includes both the tire and the rim. "

That's not consequential as it such a small change in weight, maybe 2lbs a wheel difference just using some examples off Tirerack.com. 10# is not making a noticeable difference.

It's all in the tires. If Tirerack or Consumers has tested the tires, you can see the energy efficiency of the tires.

It does look like the 19" tire/wheel combo, based on just dimensions, would give you about 2 miles an hour more range at 60 mph than the same 18" tire/wheel combo.

So stick with the 19" and get some efficient tires. I just put on the Xices for winter and I've driven the year round they are such good tires with no effect on mpg on the Subaru.

Here are four from TireRack with a 2% energy efficiency spread between them.

https://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=248

lbowroom | December 3, 2019

Range isn’t defined in number of tire revolutions.

FISHEV | December 3, 2019

“Range isn’t defined in number of tire revolutions.”

If my old wheel/tire moved the car 60 miles in one hour and new wheels/tire moves the car 62.5 miles in an hour, is that a gain in range?

Not the tire revolutions as such but the diameter of the tire determining how many miles you get per x revolutions?

lbowroom | December 3, 2019

Doesn't have anything to do with how much battery you expended.

JAD | December 3, 2019

Ignore fish as usual, his info is completely wrong.

Bighorn | December 3, 2019

@JAD
That’s implicit.

lbowroom | December 3, 2019

Don’t I know it. I just want to make sure others do too, and why.

beaver | December 3, 2019

@raqballs here is my data, enjoy

80% highway 20% city in CA
250 Wh/mile 18” aero
265 Wh/mile 18” regular (took aero covers off)
280 Wh/mile 19”

So for me aero gave 6% more range, and 19” lows another 6% compared to 18” non-aero.

Keep the 18” aeros on is my advice, you sacrificed a little handling but no change 0-60. The record P3 time of 2.98 1 foot roll was on 18” aero wheels.