Tire Sizes for 20'' Wheels

[SneakyMind]

Hello Folks

I have P85 with 21'' wheels which I'm planning to replace with 20s ( Axis MS Staggered 20x9 front & 20x10 rear) from TireRack. I'm confused with the tire sizes and after doing some research I think I have following options:
1. 245/40-20 for 20×9.0″ (front) and 275/40-20 for 20×10.0″ (rear) ( From Tsportline.com )
2. 245/40-20 for 20×9.0″ (front) and 265/40-20 for 20×10.0″ (rear) ( By TireRack.com recommendations )
3. 245/40-20 for 20×9.0″ (front) and 285/35-20 for 20×10.0″ (rear) (By Dreamin in this thread )
4. 245/45-20 for 20×9.0″ (front) and 275/40-20 for 20×10.0″ (rear) (By local tire guy as he think diameter on 245/45 will be same as 275/40)

I'll really appreciate your input, please help me deciding the best fit for my car.

Thanks in advance

 

[SomeJoe7777]

1. That is TSportline.com's recommendation, but it results in the rear tires having a circumference that is +3.6% more than the front tires. I personally would recommend that the circumference be within 1%.
2. Rear circumference is +2.2% compared to front tires.
3. Rear circumference is +0.7% compared to front tires, which is nice. However, 285 is absolute maximum width that you want to try to fit on an 10" wheel.
4. Yes, those two tires have equal circumference, but 245/45R20 will rub the front wheel wells on hard turns.

My personal recommendation would be 245/40R20 front and 275/35R20 rear. The rear circumference is -0.4% compared to the front tires (1/10 of an inch shorter in diameter).

Tirerack has a good selection of summer performance and all-season high performance tires in this size combination, including the Michelin Pilot Super Sport, Continental Extreme Contact DWS 06, Bridgestone Potenza S04 Pole Position, Pirelli P Zero, Hankook Ventus, and others.

 

[kgroschi]

1. That is TSportline.com's recommendation, but it results in the rear tires having a circumference that is +3.6% more than the front tires. I personally would recommend that the circumference be within 1%.
2. Rear circumference is +2.2% compared to front tires.
3. Rear circumference is +0.7% compared to front tires, which is nice. However, 285 is absolute maximum width that you want to try to fit on an 10" wheel.
4. Yes, those two tires have equal circumference, but 245/45R20 will rub the front wheel wells on hard turns.

My personal recommendation would be 245/40R20 front and 275/35R20 rear. The rear circumference is -0.4% compared to the front tires (1/10 of an inch shorter in diameter).

Tirerack has a good selection of summer performance and all-season high performance tires in this size combination, including the Michelin Pilot Super Sport, Continental Extreme Contact DWS 06, Bridgestone Potenza S04 Pole Position, Pirelli P Zero, Hankook Ventus, and others.

Would that be extremely optimized for acceleration your 275 recommendation for the rear or is there anything else that I am not understanding right? I am also planning on mounting 20x9 wheels all around and just don't know what tires to buy. I don't want to drag race, don't want to spend money for super high performance tires, but I do want a decent efficiency for my car. Any help would be appreciated.

 

[SomeJoe7777]

Would that be extremely optimized for acceleration your 275 recommendation for the rear or is there anything else that I am not understanding right? I am also planning on mounting 20x9 wheels all around and just don't know what tires to buy. I don't want to drag race, don't want to spend money for super high performance tires, but I do want a decent efficiency for my car. Any help would be appreciated.

The 245/40R20 on the front + 275/35R20 on the rear is my recommendation for handling and looks with 20" wheels in a staggered setup. This is a good setup for drag strip use or track use, or just spirited driving.

If you want to do 20x9 wheels on all corners (square setup), with high efficiency and mid-tier cost, there is not a perfect choice. The Pirelli Cinturato P7 All-Season Plus is reasonably close, it has high efficiency with low rolling resistance, very highly rated tire, excellent performance for a grand touring all-season tire, comfortable ride and low noise. It's drawback is that it may be somewhat more money than you want to spend at $242.20 per tire. However, it's rated for a 70K mile life, so the cost per mile is quite good.

There are 3 other options in the 245/40R20 that are less expensive, but they aren't grand touring tires (they're ultra high performance all seasons), and as such may have a bit noisier ride. In addition, they're not low rolling resistance so the'll probably have 10% higher energy use:

BF Goodrich G-Force Comp-2 A/S, $184.55
Continental ExtremeContact DWS 06, $207.20
Yokohama Advan Sport A/S, $193.55


If you want to spend less and get high efficiency, you will need to drop down to 19x8.5 or 19x8 wheels. For those wheels you'll use the standard 245/45R19 size, and you have a few options here:

Pirelli Cinturato P7 All-Season Plus, $226.20
Michelin Primacy MXM4, $219.92
GoodYear Eagle Touring T0 with sound-reduction foam, $222.20
Kumho Solus TA71, $155.55.

The Kumho is quite highly rated for comfort and performance, and is the lowest price here. However, it is not a low rolling resistance tire, and may have 10% or so higher energy use than the other options. Also, read the reviews on this tire if you consider it, it's performance seems to be quite dependent on weather conditions and type of car it's on. It looks like it may not perform well in colder temperatures or on heavier vehicles like the Tesla.

The Michelin and the GoodYear are both original equipment tires that Tesla has fit to new cars (the GoodYear is the current OEM tire). I can personally relay my experience that the Michelin Primacy's are probably the most energy efficient tire you can put on a Model S, and are one of the more comfortable choices (ride quality and noise).

All of these tires are all-season category. If you want to look at using 2 sets of tires (i.e. summer set and winter set), then there are other options for the summer 20" category.

 

[kgroschi]

Thank you very much for your elaborate answer. I really appreciate it! You had me convinced to go 275 in the rear and now I am considering to go back to 265 or even be very conservative and go with 19x8.5 rims and with stock 245s haha. So much to think about.

I do live in Socal so cold temps are not an issue for me. I do want a somewhat efficient tire and not something super sticky like I used to have on my BMWs. I do might take a turn harder here and there but ultimately I use the car to commute and want to get a good range out of my 90D since the A/C in the summer already takes a good hit on the range. I might now even go with 19x8.5 even though I think they are somewhat too small for the car. I hate the big gap between the wheel and the car. Arghhh... don't know what to do lol.

I am looking at these Verde Axis or these Niche M117 hoping to make my white car look a bit more solid.

 

[SomeJoe7777]

I might now even go with 19x8.5 even though I think they are somewhat too small for the car. I hate the big gap between the wheel and the car. Arghhh... don't know what to do lol.

Take a look at the thread 19" vs 20" pics? for many pictures of 19" and 20" wheel fitment. A stylish set of 19"s can look very nice.

 

[kgroschi]

Take a look at the thread 19" vs 20" pics? for many pictures of 19" and 20" wheel fitment. A stylish set of 19"s can look very nice.

Thanks a lot again for that. Just hard to tell with these stock tire looks. I think I will go for the 20x9 +35 offset rims all around and get 245/45 20 in the front and 265/45 20 in the rear, unless some expert tells me that's not a good way to go for whatever reason. But a set of Continental Extremcontact DWS 06 would cost a reasonable $840. I think the 245s in front might be a bit tight for the 20x9 rims but it should work from what I read.

Also, I am not sure if the +35 offset will work all around. I will have to do some more research for that as well.

 

[kgroschi]

Or 255/45 20s for the rear...? Too many choices and I don't know the effect of it.

 

[SomeJoe7777]

Well, I can tell from your posts that you're actually looking for a good look on the car more than you might state outright. You mentioned the wheel gap, you're looking at some nice matte black wheels, and twice you've suggested a staggered setup, so I suspect that your stated priorities of efficiency and ride are actually secondary.

How about this combination:

Continental ExtremeContact DWS06, 245/40R20 Front, 275/35R20 Rear

Axis MS 20x9 +35 Front, 20x10 +40 Rear Machined w/ Black Accent

Add TPMS and mounting, total package $2,132.80.


On your white 90D, these machined/black rims will look great. The 20x10 rims in the rear gives you a staggered setup, and choosing the 275/35R20 tires rather than 265/40R20 increases the options dramatically, as not a lot of tires are available in a 245/40R20 + 265/40R20 combination. The Continental ExtremeContact DWS06 is a very highly rated tire, it's an all-season, and it's rated for 56K miles.

Energy use will be somewhat higher with this setup than with a 19" LRR tire like the Primacy, but hopefully not too much. Also, this is a staggered setup which limits your rotation options. The only rotation possible is a same-axle swap (LF <-> RF and LR <-> RR). To get something close to the rated life out of these tires, you must rotate these every 4,000 miles or less. Don't skip this, or you'll be replacing these tires at 20K.

For max efficiency, keep these tires inflated to 46 psi cold. If you want to do some spirited driving or want to soften the ride, lower it to 42 psi, but be aware that energy use will go up.

Post pictures of your car once fitted.

 

[kgroschi]

Thanks a lot for that info and write up again. You are more helpful than most of the representatives I've talked to regarding this issue. Really appreciate it.

I don't like the rims you chose however. They are too close to the Tesla Turbine Wheels (TTW). They do look nice, but I want something different. And yes, you might be right. Looks are important to me, but I don't want the widest tires and lose lots of efficiency because of it. I also didn't know that you have to rotate tires that often. When it comes to tires I am such a noob.

To me, I want a thicker sidewall for protection and ride comfort, that's why I thought of a 265/40 instead of anything /35.

I will keep looking around but hope to pull the trigger soon. Thanks a lot!!!

 

[SomeJoe7777]

Thanks a lot for that info and write up again. You are more helpful than most of the representatives I've talked to regarding this issue. Really appreciate it.

I don't like the rims you chose however. They are too close to the Tesla Turbine Wheels (TTW). They do look nice, but I want something different. And yes, you might be right. Looks are important to me, but I don't want the widest tires and lose lots of efficiency because of it. I also didn't know that you have to rotate tires that often. When it comes to tires I am such a noob.

To me, I want a thicker sidewall for protection and ride comfort, that's why I thought of a 265/40 instead of anything /35.

I will keep looking around but hope to pull the trigger soon. Thanks a lot!!!

I understand on the rim choice ... that's a very personal thing and ultimately you have to be happy.

Tire type and rubber composition have more to do with the efficiency than the size. The 275/35R20 Continentals are probably slightly more efficient than say, 255/40R20 Michelin Pilot Super Sports just due to the rubber compound and seasonal category. Wider doesn't necessarily mean less efficient.

As far as the sidewall height and protection, 265/40 and 275/35 are close in sidewall height (4.25" vs. 3.75"). At those heights, the sidewall will not protect the rim at all from curb rash. Even 19s are still susceptible with 45 series tires. I only chose the 275/35 instead of the 264/40 because so many more tire choices are available in 275/35. There's literally only 2 choices of 245/40 front and 265/40 rear, and neither are all-season.

A decent compromise for you might be 20x9 wheels in square setup, with 245/40R20 on all wheels, but reduce the wheel offset a bit for a little wider stance, say +35 mm. One of your choice wheels that would fit this setup is the Verde Ax.

Combine those with the Continental ExtremeContact DWS06 all-season high performance tires. This setup is a bit more efficient (not a lot) than the staggered setup, and allows much better rotation options for long tire life.

If you had your own tire shop move your existing TPMS modules to the new wheels, and have them balance and mount, you can get the 4 wheels and 4 tires from TireRack.com for $1,708.80.

 

[kgroschi]

Even 19s are still susceptible with 45 series tires. I only chose the 275/35 instead of the 264/40 because so many more tire choices are available in 275/35. There's literally only 2 choices of 245/40 front and 265/40 rear, and neither are all-season.

Ya the tire choices are a great point. And I didn't know that 275s could be as efficient as 265s but it makes sense of course.

I actually decided on the rims and really want to go with the Niche M117. I think they look spectacular.

Why do you keep suggesting all-season tires btw? Do they have a better roll efficiency? I live in LA and never need winter tires and always had summer high performance tires on my BMWs.


Thanks!

 

[SomeJoe7777]

Why do you keep suggesting all-season tires btw? Do they have a better roll efficiency? I live in LA and never need winter tires and always had summer high performance tires on my BMWs.

Fair question -- yes, you can get great performance out of summer performance tires which will almost always exceed all-season tires performance. However, trying to use summer tires year-round can be problematic.

Even though LA doesn't get ice or snow, you do occasionally get cold/wet temperatures. Summer tire rubber gets stiff in colder temperatures (<45 deg F) and will lose almost all grip, especially if it's both cold and wet. The Telsa is a heavy car, and once the traction breaks loose, you're going to be skating. I think it's unsafe to run summer tires in the winter months, no matter what climate you have.

Summer tires also have lower tread life than all-seasons, and have higher energy use as well. Both of those characteristics occur because when it's hot the rubber is softer.

You mentioned that performance suitable for track-use wasn't a huge consideration, so I don't think a max performance summer tire is the best fit here.

Now, if you eventually plan to get 2 sets of tires and switch them for the winter and summer months, then by all means use a summer tire on one set and all-season or all-weather tires on the other set.

By the way, you may have to special-order that Niche wheel in a 20x9, that site you referred to doesn't look like they have the 20x9 size in the Tesla's offset and bolt pattern.

 

[kgroschi]

Fair question -- yes, you can get great performance out of summer performance tires which will almost always exceed all-season tires performance. However, trying to use summer tires year-round can be problematic.

Even though LA doesn't get ice or snow, you do occasionally get cold/wet temperatures. Summer tire rubber gets stiff in colder temperatures (<45 deg F) and will lose almost all grip, especially if it's both cold and wet. The Telsa is a heavy car, and once the traction breaks loose, you're going to be skating. I think it's unsafe to run summer tires in the winter months, no matter what climate you have.

Summer tires also have lower tread life than all-seasons, and have higher energy use as well. Both of those characteristics occur because when it's hot the rubber is softer.

You mentioned that performance suitable for track-use wasn't a huge consideration, so I don't think a max performance summer tire is the best fit here.

Now, if you eventually plan to get 2 sets of tires and switch them for the winter and summer months, then by all means use a summer tire on one set and all-season or all-weather tires on the other set.

By the way, you may have to special-order that Niche wheel in a 20x9, that site you referred to doesn't look like they have the 20x9 size in the Tesla's offset and bolt pattern.

Mhm, thanks for the input again. I have always had summer tires all year around and never had problems with it. I used to drive some M cars before the tesla and loved to play with the tail, but that all might be a bit different in a Tesla haha. I will think of all season tires.

I will definitely only get one set of tires though

Really? Tesla's offset is 35mm though and 5x120 right?

 

[bsmith60]

Has anyone tried the Michelin Pilot Super Sport 245/40-20 made for Porsche? It has 10 inch tread width. If it would fit it seems like this would be a good solution for front and rear, allowing for tire rotation and still giving maximum traction. The super sports are very highly rated tires.

 

[SomeJoe7777]

Really? Tesla's offset is 35mm though and 5x120 right?

Bolt pattern is 5x120, center bore is 64.1 mm. Stock offset is +40 mm, most aftermarket wheels for the Tesla are +35 mm. When I picked the Tesla model S from that site, your wheel style only showed up in a 19x8.5 size.

 

[kgroschi]

Has anyone tried the Michelin Pilot Super Sport 245/40-20 made for Porsche? It has 10 inch tread width. If it would fit it seems like this would be a good solution for front and rear, allowing for tire rotation and still giving maximum traction. The super sports are very highly rated tires.

Sounds like a good solution but it sounds expensive as well.

Bolt pattern is 5x120, center bore is 64.1 mm. Stock offset is +40 mm, most aftermarket wheels for the Tesla are +35 mm. When I picked the Tesla model S from that site, your wheel style only showed up in a 19x8.5 size.

Ya I wouldn't go by these sites. They don't have all fitting variations in the system always. I had the same issues before. I mean they won't let you put any 22s on the Tesla for example. I saw the rim is available in 20x9 +35 offset. That should work all around I'm hoping. Just haven't decided on the tires yet haha.

 

[PaulusdB]

Max tyre width on 9" rim is 265, @kgroschi.

More relevant info to be found here: Visual Tyre Size Calculator | Kouki Tech

 

[kgroschi]

Max tyre width on 9" rim is 265, @kgroschi.

More relevant info to be found here: Visual Tyre Size Calculator | Kouki Tech

Oh really??? I did not know that. And 10" are too big for the rear huh? Than I should maybe do the square set up of 245/35 20.

 

[PaulusdB]

My 20" setup has 245/40-20 on 8.5" ET32 and 285/35-20 on 10" ET35 (Michelin Pilot Super Sport).

Conforms very well to the original 21" Performance Plus setup.