Letter next to the aspect ratio

[ChocolateFrog]

As an example.

225/50Z/R18 89V

What does the Z stand for? The Internet has failed me.

[RoadToad84]

Speed rating. Can't remember what the figures are now, but Z is one of the higher ones

[ChocolateFrog]

So why does it contradict itself with the V which is for 149mph IIRC?

[BlackTails]

Isn’t that the tyre construction letter? It’s usually R for radial. You sometimes see ZR though which is a speed and construction rating. ZR means good above 149mph but the final letter gives you the max rated speed.

It’s more likely the tyres are marked 225/50 ZR18 [xxx]. Do you have a photo? V seems incongruous.

Edited by BlackTails on Monday 17th February 17:11

[mmm-five]

[mmm-five]

ChocolateFrog said:

So why does it contradict itself with the V which is for 149mph IIRC?

• V is for upto 149mph
• ZR/Z is for over 149mph

But other codes have come in such as:

• W up to 168mph
• Y up to 186mph
• ZR/Z(Y) over 186mph

[ChocolateFrog]

BlackTails said:

Isn’t that the tyre construction letter? It’s usually R for radial. You sometimes see ZR though which is a speed and construction rating. ZR means good above 149mph but the final letter gives you the max rated speed.

It’s more likely the tyres are marked 225/50 ZR18 [xxx]. Do you have a photo? V seems incongruous.

Edited by BlackTails on Monday 17th February 17:11

Think you might be right. Got it second hand from my brother who wrote it as I did.

I've asked for a picture but it's got to be ZR I think.

Not something I've seen before.

[stevieturbo]

ChocolateFrog said:

As an example.

225/50Z/R18 89V

What does the Z stand for? The Internet has failed me.

Post an image of an actual tyre with this. I've never seen one like that

Your ZR and also V would contradict each other somewhat

[MustangGT]

RoadToad84 said:

Speed rating. Can't remember what the figures are now, but Z is one of the higher ones

Don't think so, the speed rating comes immediately after the load rating, 89V in the OP post.

[Pica-Pica]

R came in to signify a radial tyre (when there were still cross-ply tyres)
Then ZR came in to indicate high speed capability (of around 150mph maximum)
Then as cars became faster, the Z was dropped and the R remained with a speed index code after the load index.
So we have (as others have stated)
V for up to 149mph
W for up to 168mph
Y for up to 186mph
A lower speed rating of H is retained for up to 130mph (you won’t often see ratings lower than H)

So my rear tyres are 255/40 R18 95Y
And my wife’s car has 195/55 R15 89H

I would like to see a photo of a modern tyre with ZR on it !

[BlackTails]

One of two cars we have with ZR tyres.

[Vsix and Vtec]

In that photo, 103Y is your load (103) and speed rating (Y)

[BlackTails]

Vsix and Vtec said:

In that photo, 103Y is your load (103) and speed rating (Y)

The speed rating is ZR(Y) - > 186mph.

[Pica-Pica]

The Z is redundant

[stevieturbo]

It's a bit odd.

Although ultimately, the 103 is the load and the Y the speed, regardless of any other lettering.

[BlackTails]

Not according to the table upthread.

Y is good for up to 186.
ZR(Y) (or just (Y) as some tables have it) is good for over 186.

[Kawasicki]

ZR(103Y)

Over 186mph, a specially made tyre, with an agreement between tyre and car manufacturer for precise load and speed and operating conditions.

[ChocolateFrog]

Finally got a picture, think that clears it up.

A over 168mph rated tyre seems a little overkill on a volvo.

[E-bmw]

I know you will likely already know this, but just because they are fitted doesn't mean they are needed.

That rating could have been on stock that day, or on offer that week, not everyone is 100% vigilant about fitting the correct spec.