Michelin PSS 245/35/20 and 285/30/20 "K1" Ferrari Spec vs Normal

Since this will be a popular tire choice for the F10 I figure this will benefit others when they search on this topic and save them some headache.

Here is the deal with the Michelin PSS in "Ferrari K1" spec compared to the normal spec tire.

1) The Ferrari "K1" spec tires ARE different compared to the normal non Ferrari tires

2) The "K1" spec starts out with less tread wear. For the 245/35/20 size it starts out with 9/32 tread where as the normal tire is 10/32. Barely any difference but.....the 285/30/20 K1 Ferrari tire starts out at just 7/32 tread where as the normal tire is 10/32. You are basically losing 30% of tread right off the bat to save weight (more on that later).

3) The tread design pattern is the same but the grooves in between the tread columns on the K1 tire is wider. You have to see the tire side by side to see the difference.

4) The K1 Ferrari tire tends to be lighter weight than the normal tire. For the 285/30/20 size the K1 tire is approx 2.6lbs lighter. This doesn't mean its only from shaving down the tread of the tire because the overall diameter of both tires is exactly the same according to Michelin's specs.

5) Now here's the kicker. Since i originally ordered the K1 spec tires for both the front and rear just to find out now that Tirerack also sells the Normal version non K1 tire in the 285/30/20 size, I called to exchange the tires since i haven't mounted them yet. Now that i have both sets of the tires in front of me the K1 tire has a different profile sidewall and is also much stiffer than the normal non K1 tire. The K1 tire's sidewall is more rounded and has more of a stretched look while the normal version is a more traditional blockier sidewall (less stretch look). You can tell just by looking at the tire without them being installed on a wheel. The part that worries me is that the K1 tire will probably have stiffer ride comfort (better handling) compared to the non K1 version. I believe this is due to the K1 tire having a higher speed rating than the normal tire. Not sure.

6) The "K1" tire also cost more. TR has the rear tires for $406 each while the normal version is $359 each for the 285/30/20 size.


Alan

Just had a Michelin rep call me back and he assured me that the tires perform 99.9% the same. Both version have the same speed rating which is different from what is shown on Tireracks website.

He can't explain why one of the tires sidewall is more rounded and why one of them feels stiffer to the hand but just said as long as these tires are mounted on the same axle there is no need for concern.

On tirerack, the non-K1 285/30/20 has 0.7" more tread width, is that what you see? If the grooves on the K1 are also wider, but has the same pattern, does the K1 skip a column?
The narrower groove pattern but same tire width leads to the rounded sidewall you're talking about?

Try bouncing them up and down vertically on the ground or hit them with a large metal tool to feel if the rubber compound is any harder/softer..

For the same size tire, the non K1 gives a larger track for better grip, but would be a little less nimble.. probably suited for their indicated purposes

Same number of columns on both tires but one of them is wider in the non K1 tire.

Picture (K1 Ferrari spec left and Normal PSS on the right)

Notice how two of the columns on the normal spec tire (right) is wider and the tread looks deeper which makes sense. K1 tire starts out at 7/32 tread while the Normal tire starts out at 10/32.

Side wall difference (K1 Ferrari on top and Normal PSS on the bottom)

You can see how the K1 tire on top have a more rounder profile where as the normal spec tire on the bottom has a more square sidewall.

According to the Michelin website and the rep that called me both of these tires have a 99Y load/speed rating and all of the specs are identical.

Alan

I see, those are two quite different patterns, more cousins than brothers.
The basic 'philosophy' in threads is the same, the application quite different -even in the left most outer columns the crossthread width differs..
Good to see the tiremaker really have customised the tire for different applications, but how can we know which one is better without trying it?
Nice pics.

add: Here's what I do, K1 on the front (rounder sidewall for better turning), normals rear (larger contact/smaller groves for better comfort)
(I take no responsibility of course..)

I am wondering if Michelin did this strickly to save weight. Saving almost 3lbs per tire is a lot and makes a difference in such a high performance car like a Ferrari.

Maybe the sidewall looks different is because theres less tread on the K1 tire but the overall diameter needs to still stay the same. What they had to do was make the tire bigger with shallower tread depth where as the Normal spec tire is smaller but with deeper tread which is impacting how the sidewall looks.

grimlock wrote

add: Here's what I do, K1 on the front (rounder sidewall for better turning), normals rear (larger contact/smaller groves for better comfort)
(I take no responsibility of course..)

lol this will be my exact setup.

Since my car will be an xdrive car i need to keep the rolling diameter as close as possible and the 245 tire up front only comes in one version, the K1 spec.

I didn't mind it up front since i'm not losing any tread wear but the rear size was nuts. 7/32 for a brand new tire?! Thats why i exchanged them for the normal spec version and will be running that in the back.

Spoke to two different Michelin reps and they both said that these tires will handle exactly the same. Who knows though...they didn't sound like engineers so....

Alan

Maybe, it could allow them to round down on a few performance figures..
Also, who drives their ferrari tires into the ground? I thought they spent most of the time in garages, and driven once a week if lucky?

Maybe, have you put the two with threads facing? Rounded edges may be a feature, it would effect how the turn-in is..

Alan l. wrote

lol this will be my exact setup.

Since my car will be an xdrive car i need to keep the rolling diameter as close as possible and the 245 tire up front only comes in one version, the K1 spec.

I didn't mind it up front since i'm not losing any tread wear but the rear size was nuts. 7/32 for a brand new tire?! Thats why i exchanged them for the normal spec version and will be running that in the back.

Spoke to two different Michelin reps and they both said that these tires will handle exactly the same. Who knows though...they didn't sound like engineers so....

Alan

kidding right?

Didn't know you had x-drive.. maybe not such a good idea for that
I have 225/45/19-8 Pzero Nero and 255/40/19-9 Conti DW but mine is RWD so although I am not an engineer I thought that was safe. Its a great combo, I am thinking of changing fronts to PSS when they wear in 2+yrs (my tires should last 4yrs if i don't get a puncture )

The rolling diameter has to be the same, esp for X-drive..

Oh well, just do it and blame tirerack if something comes up..

The rolling diameter for the 245/35/20 front and the 285/30/20 rear is identical so it is a perfect setup for xdrive or rwd cars. I originally wanted 255 up front but that might screw with the xdrive since it is about 1% difference or 1mph slower than the rear.

Alan

Great reseach, and a surprisingly big difference in tred pattern and depth I must say.

But are you sure there only one 245/35/20, the K1 version, because I'm seeing normal vertion too, but with a 91 load index.

http://ssl.delti.com/cgi-bin/rshop.pl

http://dekkmann.no/no/priskalkulator/?Bredde=245&Profil=35&Felgdiam=20&type+dekk=sommer&medlemskap=NAF

^^ Could be that is isn't being offered in the US.....yet.

The Michelin website only shows one version for that size.

Here is my new setup. 245/35/20 K1 spec PSS on the left and 285/30/20 non K1 tire on the right. You can see how the shape of the sidewall is slightly more round on the K1 tire.

So I had the non K1 Michelin Super Sport installed on my car.

The same 285/30-20 on a 10.5 rim.

Wow!!! Problem solved!!!!

No more stretched look...there's a tiny gap that looks normal running this setup but the huge gap and stretched look I had with the K1's is gone

Thanks Alan for your insight...much appreciated. I'm a happy camper

Glad i could help

Now go post up some pictures so we can see the difference!

Alan

before:



after:



That's a considerable difference!!!

wow that is a HUGE difference. Looks 10x better now!

Do you have a picture of how the K1 spec front tire looks?

Alan

245/35/20 x9 front and 275/30/20x10 rear non K1 works good for x drive as well.

How's the comfort & road noise quality?

F10 HRE wrote  

How's the comfort & road noise quality?

They're great.

They're a little stiffer feeling than a taller profile tire but since BMW fits their cars with run flats from the factory which tend to be very stiff due to the reinforced sidewall, the Michelins perform very close.

I have 20" rims and ACS springs which contribute to a harder ride yet I find the road noise and ride quality is very close to my stock M-Sport pack 19" rims that came with the car.

nwills wrote  

F10 HRE wrote  

How's the comfort & road noise quality?

They're great.

They're a little stiffer feeling than a taller profile tire but since BMW fits their cars with run flats from the factory which tend to be very stiff due to the reinforced sidewall, the Michelins perform very close.

I have 20" rims and ACS springs which contribute to a harder ride yet I find the road noise and ride quality is very close to my stock M-Sport pack 19" rims that came with the car.

Nice, good to know & thanks for the review. I'll most likely get these tires when my current tires wear out.

Where's the best place to purchase the non-Ferrai Michelin?