My two cents swapping from 21" to 19" Pirelli for winter

[jhs_7645]

I know a lot of people have done the swap from 21" to 19" for the winter, but I wanted to give folks my thoughts after doing the swap yesterday, having spent 6 weeks driving in the cold/rain on the 21" tires.

• Efficiency: I don't know what the exact specs for rolling resistance are, and how they might be different in the rain, but I can without a doubt say that I'm already seeing much better range. At least 10% but in places, it seems like even more. I've never taken a trip and gotten less than 300Wh/mi (usually around 360), and the first 10 miles on these tires were at 290.
• Handling: I'm very sensitive to the handling of this car in the rain, the traction control and ABS do a wonderful job of keeping the car stable in not so stable conditions. After I had about 30 miles on the 19" tires, I hit a freeway ramp that I hit every day in the 21" and even in the rain I felt like I was completely stuck to the road. The grip was far and away better in the wet (temps hovering around 40º) than the 21". I actually feel like I can relax a little bit and I didn't even know I was tense!
• Looks: 1 hour trip back from the service center, two thumbs up and one honk. Yep, these tires/wheels don't make my car look like a [insert your typical family sedan here].

Bottom line, I'm very pleased that I made the swap even though the winter days are waning, the truth is it won't really stop constantly raining up here for a few months anyway, so I'm going to get plenty of use out of them. Also, whenever I run through my current 21" I'm going to look for a set that performs better in the rain. I'm not very impressed with the Continentals. I don't think I realized how bad they were until I got these tires.

 

[Kaivball]

21's came with high performance summer tires.

An all season tire will always outperform this tire in wet and snowy conditions.

However, the high performance tire will run circles around the all season in dry conditions.

Each tire has a purpose.

 

[brianman]

Also keep in mind that we've had a weather change. I've been getting 20-50 Wh/mi better than previously, and it's definitely not due to more conservative acceleration use.

 

[andrewket]

21's came with high performance summer tires.

An all season tire will always outperform this tire in wet and snowy conditions.

However, the high performance tire will run circles around the all season in dry conditions.

Each tire has a purpose.

Some high performance tires will outperform all seasons in wet (not snow). Tire rack has a good article comparing various options. I would have preferred a 19 performance option. Given the choice between 21 perf and 19 all season at the same price the 21 wins in my book.

 

[dsm363]

They would sell a ton of turbine black performance rims in 19" size. Would definitely buy that.

 

[jhs_7645]

One more thought now that I've driven on the 19" for a bit:

IMO if you get the 19".. don't get the performance model S.

Acceleration is severely limited by the lack of traction. I would love to see the 0-60 numbers from a standard 85kWh w/19" v. a P85 w/19". Or for that matter, an 85kWh w/21" wheels v. a performance w/19". I'm willing to sacrifice performance during the winter, but the moment I see solid warmer weather on the horizon, I'm going back to the 21".

 

[ElSupreme]

One more thought now that I've driven on the 19" for a bit:

IMO if you get the 19".. don't get the performance model S.

You can always get good sport tires for the 19" rims. The rim size really isn't going to matter all that much.

 

[Al Sherman]

They would sell a ton of turbine black performance rims in 19" size. Would definitely buy that.

Me too except I'd get the silver. In fact, sometime before November I'm going to. I'll certainly buy them from Tesla if they offer them. I'm definitely getting them before next Winter regardless.

 

[jhs_7645]

You can always get good sport tires for the 19" rims. The rim size really isn't going to matter all that much.

Good point. Data would be interesting here. I'd imagine that the 21" Continentals are not as good as others as well.

 

[rolosrevenge]

I'm curious to see how drag times would compare if you had the same type of sport tires. 19" will reach top speed faster, but a lower top speed.

 

[Robert.Boston]

I'm curious to see how drag times would compare if you had the same type of sport tires. 19" will reach top speed faster, but a lower top speed.

Not really, because the outer circumference is the same. With a 19" rim, the sidewalls are about 1" taller.

 

[rolosrevenge]

So then what's the performance advantage of 21" wheels if the tires are the same?

 

[ElSupreme]

So then what's the performance advantage of 21" wheels if the tires are the same?

Well in theory you get a shorter (and thus stiffer) sidewall with the larger rims. More Aluminum less rubber. For the same overall diameter. Which lessens the amount of lean the tires will have when cornering. But you generally pay for larger rims with a higher moment of inertia. There is a fine line between too big and too small rim size. In reality the weight and moment of inertia (weight and its location) are going to play a bigger factor than size between 19" and 21". And with modern tires it would be doubtful that a 35 profile tire would really be stiffer than a 45 profile tire.

But driving on a street you wouldn't be able to tell the difference (assuming comparable tires) between the two. And even on a track I doubt anyone but highly experienced racers would be able to tell the difference.

Coming from the factory the performance advantage is tires. Nothing to do with rims.

 

[100thMonkey]

now that I've gotten a jack and installed the gators I'm less sheepish about the idea of having an extra set of tires and just swapping out for the summer and fall, we'll see. too bad someone hasn't come out with an all season 21' tire, kind of hoping someone will! I have had one somewhat alarming fish tail so far in the wet but now I know the limits better.

 

[rolosrevenge]

Well in theory you get a shorter (and thus stiffer) sidewall with the larger rims. More Aluminum less rubber. For the same overall diameter. Which lessens the amount of lean the tires will have when cornering. But you generally pay for larger rims with a higher moment of inertia. There is a fine line between too big and too small rim size. In reality the weight and moment of inertia (weight and its location) are going to play a bigger factor than size between 19" and 21". And with modern tires it would be doubtful that a 35 profile tire would really be stiffer than a 45 profile tire.

But driving on a street you wouldn't be able to tell the difference (assuming comparable tires) between the two. And even on a track I doubt anyone but highly experienced racers would be able to tell the difference.

Coming from the factory the performance advantage is tires. Nothing to do with rims.

That's good to hear. I'd like to get into serious drag racing with it, but also want to be able to do record breaking distances, the latter wants the smaller wheels I hear but the former I'm not sure.

 

[bosgig]

Given the prior winter wheel shortage I decided just to leave my 21's on for this winter and deal with the tire swap next winter, figuring I'd just leave my S in the garage when it snows this season (I held on to my old car for now which I can use in snow if I need to). I got the Michelin 21's and have had no problem at all on wet roads. I woudn't say I've necessarily pushed them to their limit in rain (and don't intend to), but nonetheless I've had no problems on wet pavement.

 

[Doug_G]

The grip under acceleration depends on the tire compound, not the sidewall height. The extreme low profile tires are mostly about cosmetics, but generally speaking stiffer sidewalls are better for cornering.

 

[ElSupreme]

The grip under acceleration depends on the tire compound, not the sidewall height. The extreme low profile tires are mostly about cosmetics, but generally speaking stiffer sidewalls are better for cornering.

Yes this. There is a reason why dragsters have huge sidewalls.

And if you look at racing vehicles (F1, ALMS, other) you don't see monster rims either. You will see a decent amount of sidewall also.

 

[jerry33]

Monster wheel diameter is mostly about markup and profit. It also allows a vehicle manufacturer to use larger diameter brakes (assuming they don't use inboard brakes).

 

[yobigd20]

One more thought now that I've driven on the 19" for a bit:

IMO if you get the 19".. don't get the performance model S.

Acceleration is severely limited by the lack of traction. I would love to see the 0-60 numbers from a standard 85kWh w/19" v. a P85 w/19". Or for that matter, an 85kWh w/21" wheels v. a performance w/19". I'm willing to sacrifice performance during the winter, but the moment I see solid warmer weather on the horizon, I'm going back to the 21".

I 100% completely disagree. I downgraded my P85 to the 19s because of poor roads and pothole city , but I have had no issues with traction when flooring it. It is crazy fast. I have a hella fast car, and I get better performance in rain, longer range than the 21s, and a much smoother ride. The 21s are really only for cosmetic look and not worth the maintenance headache and price IMO.