Hi, There is a conflict between the table in the handbook and the sticker on the door for the tyres. This has prompted some questions.

1. The door sticker suggests I can use a 255/35R20 97Y whereas the manula shows it should be a 255/35ZR20 97Y.

I have read that either is suitable - can somebody please confirm?

2. There is a choice of 3 different sizes for both front and rear.3. Must I stay with the Dunlops or Pirelli or could Hankock or Goodyear be installed (these are much cheaper - but I am unsure if there are suitable replacements)?

4. The dunlops on the car at present are very noisy - is this normal for dunlops? Does anybody have experience of other makes?

Thanks for any help

Simon

 

Simon:

The Z is the just the speed rating, there is no difference in size. You don't have to stick with Dunlop if replacing all four. Hankook are suppose to be making nice tires for the money. I am a fan of Bridgestone or Michelin. Pirelli can be hit of miss. I assume in Dubai, summer only tires would be fine. Check out Bridgestone SO4's; don't break the bank fwiw.

 

How to read a Tyre?

Until someone comes along to give you the answer, read the above url and look at the jpg I attached with the underlined in red line. ZR it seems to indicate one fast tire and that ZR has to be on the tire due to some regulation of DOT. EDIT: Sorry, didn't see the post above mine. Too late.

That said, my 2007 is too noisy on certain road surfaces. Those particular surfaces usually look like rough aggregate material. Fortunatley I don't encounter a lot of that type road surface, but when I do, the rear tires especially transmit a Lot of noise. Smooth asphalt surfaces are just fine with me and the car. Concrete surfaces with a lot of expansion strips are NOT fine with me and the car.

 

Thanks for the replies. If the last letter on the code is a Y indicating that the speed rating is 300KPH, wouln't that mean the Z in the ZR is not needed. Dont they mean the same or similar thing?

Thanks

Simon

 

The 3 different specs on the door sticker are for 18", 19" & 20" wheels; same with the specs in the table - what size do you have? Since you mention the 20" tyre, I'm guessing it may be that - in which case, you need 255 front, 285 rear.

The table from the manual is for "arduous terrain", i.e. rough, unsurfaced roads. If you spend most of your time on tarmac, I suggest you ignore those. If you do spend time out on unsurfaced desert roads, pick the tyres appropriate for your wheel size.

ZR tyres have a reinforced radial construction for very high-speed driving - if you have an unmodified XK, it will be limited to 250 km/h, so you won't come near the 300 km/h rating of a ZR tyre. I'm not sure why the door sticker recommends ZR 18" tyres but R for 19" & 20" - perhaps the forces on the sidewalls are greater with the smaller wheels.