Gretch

Third yea vote on the yoks....I run them on both P cars.....(when I am not running slicks on Gretch)

AO

Beginning in 1991, the speed symbol denoting a fixed maximum speed capability of new tires must be shown only in the speed rating portion of the tire's service description, such as 225/50R16 89S. The most common tire speed rating symbols, maximum speeds and typical applications are shown below:

M 81 mph 130 km/h
N 87 mph 140 km/h Temporary Spare Tires
P 93 mph 150 km/h
Q 99 mph 160 km/h Studless & Studdable Winter Tires
R 106 mph 170 km/h H.D. Light Truck Tires
S 112 mph 180 km/h Family Sedans & Vans
T 118 mph 190 km/h Family Sedans & Vans
U 124 mph 200 km/h
H 130 mph 210 km/h Sport Sedans & Coupes
V 149 mph 240 km/h Sport Sedans, Coupes & Sports Cars

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.

W 168 mph 270 km/h Exotic Sports Cars
Y 186 mph 300 km/h Exotic 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.

225/50ZR16 in excess of 149 mph, 240 km/h
205/45ZR17 88W 168 mph, 270 km/h
285/35ZR19 99Y 186 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 99Y 186 mph, 300 km/h
285/35ZR19 (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.

Mark

Andrew - EXCELLENT Info!

jheis

Geez, I would NEVER put chinese tires on my car - no matter what their speed rating is.

I may be cheap, but somethings are worth the price.

James

michaelathome

944s Boyeee,

I don't think that I would have bought those tires, I saw it earlier in the threadmentioned by some one else, take care of your car, it can be expensive.

Andrew,

It kinda looks like you pulled that right off of Tire-R__K's site, not fair, they are trying to sell you the "Best" tire they can fit into your budget.

IIRC tire ratings were designed with a maximum speed/load/heat/friction based upon 24hr or longer sustained runs with little or no stop. I have looked at several sites including http://www.safercar.gov/ but I couldn't find anything above C rated tires going outside of manufacturers sites.

Once again IIRC it is really friction and heat involved w/tire rotational speed that cause the problems. Problems with things like belt separation and tread loss were more of an 80's and 90's thing and that is what has forced some of the changes that we see today in ratings.

I have owned BFG's Yoko's and Mich's and have never had a problem outside of flats with any of them at any speeds. I guess I shouldn't bring up tire age here and now.

Getting back to things 944s Boyeee, you will likely have a VERY soft ride, enjoy it while you look for the new set (all 4)!

Michael

FlyingDog

michael, tire ratings are based on the sidewall's ability to maintain form at high speed. It has nothing to do with friction.

michaelathome

FlyingDog,

You can be doing 10mph and spinning your wheels at the equivalent of the same tire with a rotational speed of 200mph? You don't get that? There is no heat or "friction" involved? There are other factors involved? I thought the ony tires built w/out a "radial" form of support were the ones on my lawnmower or my "Radio Flyer!"

Oh, I forgot about the radial expansion of drag tires. I guess they may not have that kind of radial support. They are real cars aren't they?

Michael

FlyingDog

You can have a 200mph rated tire with almost no friction. You can have a 50mph rated tire that's stickier than used bubblegum. The speed ratings are the tires ability to maintain form at that speed, not the tires ability to get you to that speed or hold a corner at that speed. I didn't say heat wasn't involved, but it is only indirectly in that it effects the tires ability to maintain it's form at high speed.

Drag tires weren't speed rated like regular tires last time I checked.

Barry Johnson

Personally, I run the Hankook Sport K104s on my S4, and they (although don't have many miles on them), seem to grip pretty well, aren't very noisy, and have the price, tread pattern, and speed rating I'm looking for.
I've also heard great things about those ES100s, and the sidewall is good looking too, which is important if you want an agressive looking tire.
I'd get either one, but we'll see how these K104s do over time...

UKKid35

There's little chance your insurance company will settle any claim if you were to be involved in an accident and tyre condition (and type) is routinely checked by assessors in serious cases.

AO

I posted the link first, but it didn't look like anyone was following it, so I posted the text. Didn't mean to mis-represent.

Jeff928S4

Andrew - thanks for the link (and subsequent posted info)!

Garth - here is the info on the tire itself......

Hankook Ventus H101
Tread - 2 steel, 2 polyester, 1 nylon
Sidewall - 2 polyester
P245/50 R16 96H

This tire is "S" rated on some sites and "S/H" rated on others.

Now on the front - I could not even find a name on the tire. They say HPZ-760 225/50/ZR16; the only thing that was a "word" was "Made in the U.S.A. Mentor". I searched "Mentor HPZ-760" and got no results at all. They look to be the correct speed rating - what with the "ZR" in the size (thanks to Andrew again). The tread pattern is very similar to the Hankooks on the rear.

In an older post - Garth said........."For an amusing comparison, other tires in common use (rear) on 17" wheels are 255/40R17 at 25.1", 827 revs/mile - some even use 275/40R17 at 25.7" od, 809 revs/mile: this is the same as the 245/50R16. Jump to 18" rears, and the commonly used size is 265/35R18 at 25.3" od and 819 revs/mile.". I will be going back to get different tires today and wanted to know if these sizes Garth mentions will fit on my car. Garth mentions 17" wheels - wouldn't I have 16" wheels?....thus making these sizes unavailable to me?

Jeff928S4

**UPDATE**.

Ok - I'm an idiot - the "Mentor" on the front tire apparently is where they were made...."Made in the U.S.A. Mentor" - duh!!

Now these HPZ-760 tires are either Mastercraft (I didn't know they even made a high-speed rated tire) or Hercules (which would be good, because I know the place I got my tires from sell Hercules tires). Anyone hear of the "HPZ-760"???

928fan4life

what about cooper tires? Are they any good? here is a link to there ultra high performance tires.

http://www.coopertires.com/us/en/Pro...itle=UHP+Tires

WER

The cooper looks good, but they don't have anything in 245-45-16, which is what he'll need on the rear of an S-4.