jsnbd3ll

So I have been told that my RX-8 requires Z rated tires. Now Z rated tires are rated to withstand 186 mph. That is great and all but there is no way my *** is ever getting close to that speed. So with that being said, if I put W rated tires (168 mph) on my car, am I in any danger? Please help!

Wilson

I think your numbers off a bit.

Z = <149 mph
W = 168
Y = 186

You can check it out here.

jsnbd3ll

Ok, I stand corrected. So what rating tire should I have on the RX-8? Should it be a Z, W or Y? Please help!

Wilson

It comes with W rated tires. You could go with less if you don't drive at high speeds. How low would be a question that only you can answer, depending on the speeds you drive.

That said, you might have a hard time finding something like an H rated tire in the sizes we use.

jsnbd3ll

Thanks for the fast responses Wilson. I am looking at putting a new set of wheels on and have been checking prices like crazy. I have staggered wheels ( I know, I know). The front will be 245/40 and the rear is still up in the air. I am leaning towards 275/35 rather than 265/40 mainly because of the cost. But I will not be putting a H rated tire on my car. The tires I am looking at are a good buy and are rated Y. I was just curious about what was really required for the RX-8.

RX26b

Actually, it's your #s that are off. Z, as along as I remember, have been speed rated at 150+. This from back in the days when there were only V & Z for high performance cars. V was up to 149, and Z took over from there.

Wilson

I was 2 miles per hour off. (Z in the size signifies a maximum speed capability in excess of 149) That would mean 150. Thanks for catching that for me. I also did not notice my mistype. I put 148 and meant 149, but that would have still been off by 1.

RX26b

Z having maximum rating of 150 mph, and V having a 149 makes no sense. Z is 150 + mph. In the old days before W and Y tires, all sports cars capable of more than 150(and even some whose top speed wasn't quite 150) received Z rubber. Porsche 959, ZR-1s, Testarossas, and tons of others with top speeds in the 170s, 190s, or over 200 were equipped with Z tires.

As written in the article you linked, manufacturers don't specify a ceiling with a Z tire; they simply say 150+. So it's a different measuring system than all other letters ( H, V, W, Y, etc.)

KimiFelipe

What your car requires is a tire with a load rating that is at least as high (e.g., 94 W) as the stock tire.

You don't _require_ Z rated tires. Whoever told you that is either lying to you or knows nothing about tires. You can run Q rated winters for example, this means nothing.

Get the stock size, or an equivalent sized tire, and you'll be fine. If you go to tirerack.com you can look up your car and it will give you lists of tires that will fit of all kinds. Start there. You can register free and then save your car info there so any time you need tires or even wheels you can look it right up.