PS2's - Two Different Speed Ratings

[Copperhead245]

Just got another set of front PS2's. Unlike my previous ones, which indicate 275/35ZR18 on them, these say 275/35R18 (and the stickers on them also say "R")...

I realize the real speed rating is the "Y" in the "95Y" following the size info, however on the "ZR" tires, the 95Y is in parentheses, while on the "R" tires its not.

The parentheses indicate "in excess of 186 mph" (without paretheses, 186 is max speed). Not that I hit 186, but most of my driving is to, on and from a track.

Anyone know what's up, did Michelin change the PS2? Did I get the wrong tires? (being Saturday morning, I can't speak to my supplier right now).

Ron

 

[Bill Pemberton Woodhouse]

Check to the right in the service description ----likely is a Y or W rating and that is the actual speed rating ( as you noted ).

Likely you are fine.

 

[Copperhead245]

As, as I noted, it is a "Y" on both sets, however the parentheses do make a difference. Since I paid for ZR's and got R's, I'm returning them...

 

[Martin]

Did you get them from one of those vendors in New York City that have really good deals on name-brand merchandise? I just got a killer Rolax watch for myself and Luis Vutton handbag for my girlfriend. They only charged me $250 for both because they said the manufacturer made some printing errors and had to clear them out really cheap, so he could give me a great deal on them. He was asking $300 but I talked him down. I'm stoked.

 

[Copperhead245]

Kind of feels like I paid for a Rolex and got a "Rolax", but I ordered them via the same vendor I got the last set - he's real close to your northern location (not his fault, as the invoice was for ZR's and they were shipped from an eastern warehouse).

 

[Black Moon]

R for 'retread'

Seriously, I think PS2's only come in one rating.

 

[AZTVR]

I would say that Luke at Tirerack would be the best source of info. I had never heard about this speed rating distinction before.

I have a set that I bought at Discount Tire that have M0 after the word "Pilot Sport" only on the outside side and are labeled 275/35R18 95Y, no parentheses, and no letter/numbers in the block after that. I didn't know about the special Viper C1 version at time of purchase; but, was later told the M0 was adesignation for Mercedes I think, and was not significantly different performance such that I would notice.

An extra tire that I picked up has 275/35ZR18 (95Y) and a C1 after it (means designated for Viper) on the outside side (No characters after the word "Pilot Sport" like on the other tire)

So, maybe that is why one set of tires is different from the other. Unless you have plans to exceed 186, I would think that it would be more hassle than it is worth to exchange them, if the Viper C1 version is even still being made.

My last PS2 fronts, which I bought through JonB, were wider 295/30ZR18 (98Y) N2 which, if you can exchange and if they fit your wheels might be a more desirable option for the track.

 

[Copperhead245]

Thanks Jim, you've confirmed what I've got...

My previous ones - 275/35ZR-18 (95Y) do have a "C1" after that and nothing after "Pilot Sport" ("PS2" is in small print under the "t" of "Sport"). My "new" tires "275/35R-18 95Y" (no parentheses), like yours, have "MO" after "Pilot Sport" (along with the same small "PS2").

And yes, eventually, I will be looking at other wheel/tire for the track, but I don't (yet) have a tralier and I am running stock sizes. I have my original Sidewinder rims with either run-flats or PS1's for the street and I've got a set of ACR (black Sidewinder) rims that I have the PS2's on.

They ARE different tires - "(95Y)" are rated "in excess of 186 mph", "95Y" rated at 186 maximum.

Since my last set of PS2's only lasted me 4 track days (outside edges worn, and can't rotate, flip, or side-to-side swap), I'm having an alignment done this week (a bit of negative camber). So, I'm at about $900 just for the fronts (tires, shipping, balanced, mounted, and alignment).

I've done the math - it cost me about $2 per mile for the last set (just the fronts, not counting the backs which are wearing but not as fast). If I average 12MPG, that's eight times as much as gas!

For that kind of $$$, they should be the best friggin' stock-size tires I can get (that are good for both street and track)...

 

[ViperGeorge]

The Mercedes spec tire was the only non-runflat PS2 that was available for the Viper a few years ago. That was because the Gen 3s came with ZP tires (runflats) while the Mercedes came with non-runflat PS2s. It wasn't until the Gen 4 came out that Viper switched to a non-runflat version of the PS2. I used the Mercedes tires on my 06 while competing in the Cannonball One Lap and I put many track miles on them. No issues. You would be fine to use them. I originally bought the Mercedes spec tire from Tirerack at their suggestion.

 

[ViperGeorge]

My guess is that the difference between the two tires is slight and is likely related to the spring rate of the tire.

 

[Copperhead245]

Agreed the difference is slight and I'll never be able to tell the difference, but has the "R"/"MO" tire been sitting on a shelf longer? I certainly did not get what I paid for...

 

[MuscleJunkie]

From my research they have both type of PS2's The (Y) and Y

(Y) Over 186MPH
Y - Maximum 186

I need to clarify but I think I remember John B explaining something along the lines that the Viper spec are new "old" tires (the ones with the (y) over 186 MPH) and to get new tires you might be limited to the "Y" (maximum 186MPH designation)

Hope this helps

 

[plumcrazy]

i wouldnt want that on my car personally. its not what you ordered. im sure the guy will make right and get the correct tire out asap

 

[Copperhead245]

Thanks Plum - we still got to meet up one of these days. Are you going to NJMS with the NJ VCA next Thursday???

 

[AZTVR]

Agreed the difference is slight and I'll never be able to tell the difference, but has the "R"/"MO" tire been sitting on a shelf longer? I certainly did not get what I paid for...

If the tire comes from Tirerack's warehouse, I believe that you can trust that it has been stored correctly, and the specific Date Code on the tire is not a significant issue in that case.

I have been exactly where you appear to be. I want "the best" for my money; and I tend to obsess a bit over it; however, in the end, I know that at my level of driving, I would never notice the difference. But, ahead of time, I don't know that I wouldn't notice, so, I go round and round in my mind.

I believe that you can trust JonB and Luke's advice. I believe that they value their reputation more than a few bucks, and would NOT tell you a tire is suitable unless their experience tells them that that it is..

 

[plumcrazy]

no, not going there.

was just blasting thru your neck of the woods 10 minutes ago. will let ya know next time.

 

[JonB]

If you crave the Z for Z sake, you will be saddened to hear it is exceeded/superceded/obsoleted.
When Z-speed rated tires were first introduced, they were thought to reflect the highest tire speed rating that would ever be required, in excess of 240 km/h or 149 mph. While Z-speed rated tires are capable of speeds in excess of 149 mph, how far above 149 mph was not identified. That ultimately caused the automotive industry to add W- and Y-speed ratings to identify the tires that meet the needs of new vehicles that have extremely high top-speed capabilities.
W168 mph270 km/hExotic Sports Cars
Y186 mph300 km/hExotic Sports Cars

My bet is your NEWEST new tires dont have the Z..... and the 2-3 year old yet 'new' tires do?

Here ya go: Z is GONE on newest-built tires, and this 'splains why:

Tire Tech Information - How to Read Speed Rating, Load Index & Service Descriptions

Were we your vendor? Gimme A Call ! I've 'splained this to a LOT of customers, a LOT of times!

 

[01sapphirebob]

Jon Helped me on this very same issue. I had got a set of PS2's from him and noticed the same thing. Bottom line. I don't plan on having the car over 186 mph for an extended period of time so the regular ps2 you have without the "ZR" rating should be fine

If you crave the Z for Z sake, you will be saddened to hear it is exceeded/superceded/obsoleted.
When Z-speed rated tires were first introduced, they were thought to reflect the highest tire speed rating that would ever be required, in excess of 240 km/h or 149 mph. While Z-speed rated tires are capable of speeds in excess of 149 mph, how far above 149 mph was not identified. That ultimately caused the automotive industry to add W- and Y-speed ratings to identify the tires that meet the needs of new vehicles that have extremely high top-speed capabilities.
W168 mph270 km/hExotic Sports Cars
Y186 mph300 km/hExotic Sports Cars

My bet is your NEWEST new tires dont have the Z..... and the 2-3 year old yet 'new' tires do?

Here ya go: Z is GONE on newest-built tires, and this 'splains why:

Tire Tech Information - How to Read Speed Rating, Load Index & Service Descriptions

Were we your vendor? Gimme A Call ! I've 'splained this to a LOT of customers, a LOT of times!

 

[Copperhead245]

Thanks Jon, that's exactly the info I read before posting. I know the "Z" means nothing anymore. If you read all the way down, however, the parentheses do mean something - with parentheses (the old "Z"), they are rated at a higher speed ("in excess of 186 mph").

But, if they can't be had, then that's that. The "Z" tires may be obsolete/superceded, but they are NOT "exceeded" by these.

 

[MuscleJunkie]

I think there might be a bit of a misunderstanding about the "z" letter being thrown out here

All of these tires being spoken of are "Z" rated tires. There are still "Z" rated tires meaning the tire is rated I believe in excess of 149MPH. You can still buy tires for various cars with just a plain old "Z" rating.

But there are also tires that have a "z" rating with an "additional" letter that further specifies to what speed over 149MPH the tires are rated for. Some tires will say ZR with the additional letter and some others will just have R with an additional letter.

Meanings of additional specification letter

W - up to maximum 168MPH
Y - up to maximum 186MPH
(Y) - Exceeding 186MPH

Looking at TireRack you will see the following

Kumho Ecsta XS have a W speed rating (up to a maximum of 168MPH)

Pilot Sport ZP Run Flats
Both front and rears currently being sold by Tire Rack are (Y) speed rated yet from the product description it appears that maybe at one time the rears were only standard Y speed rating.

Nitto Invo (not sold by Tire Rack) Nitto DOES NOT sell a matching "speed rated" set for the Viper - see below

Fronts are only W speed rated. You cannot get a matching speed rating for the fronts and the fastest (Y) speed rating is not available on fronts or rears.

Rears are standard Y speed rated


Pilot Sport PS2 (They sell multiple types of the same tire)
C1 Spec rears are rated (Y) (exceeding 186MPH)

One type of PS2 FRONTS are rated only Y (maximum 186MPH)

Another type of PS2 FRONTS (C1 spec) are rated (Y) (exceeding 186MPH)

And yet another type of PS2 Fronts are (Y) rated

So it appears with the PS2 tires you should be sure you get the C1 spec or the "other" non C1 spec (Y) rated tire if you want the fastest (Y) speed rating instead of the slower standard Y speed rating

 

[JonB]

Thanks Jon, that's exactly the info I read before posting. I know the "Z" means nothing anymore. If you read all the way down, however, the parentheses do mean something - with parentheses (the old "Z"), they are rated at a higher speed ("in excess of 186 mph").

But, if they can't be had, then that's that. The "Z" tires may be obsolete/superceded, but they are NOT "exceeded" by these.

PS2s in 275-ZR CAN be had.....but with mid-2007 production dates, and less tread.

My use of 'exceed' was/is to say that the new W and Y ratings present speeds in excess of te 149 mph Z ratings.

 

[Luke@tirerack]

ok guys ... here's the entire story

Michelin designed the Pilot Sport PS2 to be the ultimate street tire that can offer world class performance while maintaining a level of performance few tires could achieve. It is manufactured in 17" - 22" diameters for sports cars and sports sedans and two different speed ratings 'Y' and '(Y)'.

In the 275/35-18 size in question the speed rating is (Y)

here's a nice cut and paste from the tech thread that goes into more depth about speed ratings

Speed Ratings:

In Europe, where selected highways do not have speed limits and high speed driving is permitted, speed ratings were established to match the speed capability of tires with the top speed capabilities of the vehicles to which they are applied. Speed ratings are established in kilometers per hour and subsequently converted to miles per hour (which explains why speed ratings appear established at “odd” mile per hour increments). Despite the tire manufacturer’s ability to manufacturer tires capable of high speeds, none of them recommend the use of their products in excess of legal speed limits.

Speed ratings are based on laboratory tests where the tire is pressed (to reflect its required load) against a large diameter metal drum and run at ever increasing speeds (in 6.2 mph steps in 10 minute increments) until the tire’s required speed has been met.

Speed Rating - Miles/Hour - Kilometers/Hour - Typical Use
N=87 MPH, 140km/h, Spare Tires
P=93 MPH, 150km/h
Q=99 MPH, 160km/h, Winter, LT Tires
R=106 MPH, 170km/h, LT Tires
S=112 MPH, 180km/h
T=118 MPH, 190km/h
U=124 MPH, 200km/h
H=130 MPH, 210km/h, Sport Sedans
V=149 MPH, 240km/h, Sports Cars
Z=149 MPH, 240km/h and over, Sports Cars
W=168 MPH, 270km/h, Exotic Sport Cars
Y=186 MPH, 300km/h, Exotic Sport Cars

*Today, the Z-speed rating is the only speed rating that is still branded “within” the tire size, as in P225/50ZR16. All other speed ratings are shown in the tire’s service description.

When Z-speed rated tires were first introduced, they were thought to reflect the highest tire speed rating that would ever be required, in excess of 240 km/h or 149 mph. While Z-speed rated tires are capable of speeds in excess of 149 mph, how far above 149 mph was not identified. That ultimately caused the automotive industry to add W- and Y-speed ratings to identify the tires that meet the needs of new vehicles that have extremely high top-speed capabilities.
W168 mph270 km/hExotic Sports CarsY186 mph300 km/hExotic Sports Cars
While a Z-speed rating still often appears in the tire size designation of these tires, such as 225/50ZR16 91W, the Z in the size signifies a maximum speed capability in excess of 149 mph, 240 km/h; the W in the service description indicates the tire's 168 mph, 270 km/h maximum speed.

225/50ZR16in excess of 149 mph, 240 km/h205/45ZR17 88W168 mph, 270 km/h285/35ZR19 99Y186 mph, 300 km/h
Most recently, when the Y-speed rating indicated in a service description is enclosed in parentheses, such as 285/35ZR19 (99Y), the top speed of the tire has been tested in excess of 186 mph, 300 km/h indicated by the service description as shown below:
285/35ZR19 99Y186 mph, 300 km/h285/35ZR19 (99Y)in excess of 186 mph, 300 km/h

As vehicles have increased their top speeds into Autobahn-only ranges, the tire speed ratings have evolved to better identify the tires capability, allowing drivers to match the speed of their tires with the top speed of their vehicle.

Then we have the vehicle manufacturer input which is quite common in the tire world

Mercedes wanted a little nicer ride quality soMichelin made the tread depth slightly deeper (9/32" compared to 8/32") but, that added tread depth will create more heat at speed and it also weighs more so, the speed rating is slightly lower at 'Y' with a max speed of 186 mph.

Dodge wanted a little more grip so a modification was made to the rubber compound but the tread depth remained 8/32" and the speed rating was not effected and stayed '(Y)'

so, yes there are three distinctly different versions of the Pilot Sport PS2 in the 275/35-18 size

there ... now it should be clear as mud ...

here's an interesting point about speed rated tires on certain vehicles ... at the top speed of almost 268 mph the tires on a Bugatti Veyron Super Sport only last 37 miles.

 

[JonB]

............here's an interesting point about speed rated tires on certain vehicles ... at the top speed of almost 268 mph the tires on a Bugatti Veyron Super Sport only last 37 miles.

And what tires would those be, Hmmm?

 

[Luke@tirerack]

And what tires would those be, Hmmm?

Michelin PAX system runflats which can only be purchase through a Bugatti dealer

reported pricing is somewhere north of $15k a set

 

[MuscleJunkie]

And what tires would those be, Hmmm?

Probably these

Tire Search Results



J/K

 

[JonB]

Michelin PAX system runflats which can only be purchase through a Bugatti dealer. reported pricing is somewhere north of $15k a set

The only Veyron I ever saw was at Miller Motorsports Park, and he drove there from COLO. He later parked in the same block as us downtown in SLC, dinnertime. He drove it a LOT, and had a bazillion squished bugs to prove it.

It had PS2s on it, looked the same as my Viper's !

 

[Luke@tirerack]

The only Veyron I ever saw was at Miller Motorsports Park, and he drove there from COLO. He later parked in the same block as us downtown in SLC, dinnertime. He drove it a LOT, and had a bazillion squished bugs to prove it.

that would be this one ... right ?

You must be registered for see images attach

 

[JonB]

THASSIT! Note the Lambo behind it....those 2 guys drove from Colo. You can even see the bugtalities

 

[Abe Froman]

I just purchased a set of PS-2's form Discount tire, the fronts are the "95Y" M0 and the rears are (105 Y)... What does the (105 Y) indicate??

 

[MuscleJunkie]

I just purchased a set of PS-2's form Discount tire, the fronts are the "95Y" M0 and the rears are (105 Y)... What does the (105 Y) indicate??

Basically you have slightly mismatched tires which may be ok to some folks

The rears in the PS2's only come in C1 Viper Spec with the fastest (Y) speed rating (exceeding 186MPH)

Your fronts are the Mercedes Spec PS2's (instead of the matching C1 Viper Spec PS2's) with only a standard Y (maximum 186MPH) speed rating. Your fronts have 1/32 more tread than your rears and if I understand what Luke and Tire Rack told me, the Mercedes Spec tires might have a bit different tread compound than the C1 Viper Spec PS2s