Tyres - What is the difference

I have had my A6 tdi for 4 years and it has always worn

Dunlop SP9090 235/45 R17

They are up for replacement again and as ever i keep coming across

Dunlop SP9090 and Dunlop SP9000 they look the same same tread but it has worn the 9090 from new and the price difference can be £20 a tyre....

9090 235/45 R17 Y (94) - £107
9000 235/45 R17 Z (94) £81

Anyone know the difference, can i save £25 a tyre and get the 9000, does the Y or Z really make that much difference on a 1.9tdi.....

Anyone had experience of these..

Muffin

Basically its just the different speed rating.
[FONT=Arial,Helvetica,Geneva,Swiss,SunSans-Regular]http://www.tyres1.com/tech_main.html[/FONT]

Here is a link that says that the 9090 is a specially tuned version of the 9000 used by Porsche, it also sells them for 81.14 exc VAT. Not sure how they are tuned, perhaps different types of belts? Do you really need a tyre that will sustain speeds of 149 MPH? http://www.tyresite.com/product.asp?P_ID=201
It shows different tread patterns for the 9000 and the 9090, I prefer the 9000 since it looks more like the HydroEdge pattern and should be good in the wet.

The Z speed ratings is "over 149 MPH" the Y is maximum speed of 186 MPH. As you go up in ratings you lose comfort as the tires get stiffer so a H rated 130 MPH tire would be much softer than a Z rated tire.

Muffin; Here is some more info so you can make an informed choice;

http://forums.tdiclub.com/All-Season Vs. Touring Vs. Performance

All-Season tread designs will provide good all-around traction for varying road conditions such as Wet, Snow and Ice, but still provide good Treadwear & Tire Noise characteristics. Performance tread designs have been engineered to Enhance a vehicles Handling capabilities on wet and dry roads, but usually exhibit increased Tire Noise and Lack Long Treadwear Life. Performance tread designs usually have larger tread elements to provide a stiff tread area for handling performance. Touring tread designs were designed to bridge the gap between All-Season & Performance tires. Touring tread designs combine the technology for good treadwear characteristics from All-Season tires and handling & grip associated with Performance tires. Touring tires also exhibit very good Tire Noise and Ride Comfort.
http://forums.tdiclub.com/Treadwear Performance Vs. Grip/ Handling/ Traction Performance...

The treadwear-traction trade-off has been a focus in Tire Performance-Enhancement Technology for decades. Tire companies have been trying to reduce the trade-off between treadwear & traction through the development of new rubber, new tread designs, and new tire construction techniques. Basically, a tire will wear-out quickly if it is providing maximum grip to the road. This is due to the tread rubber being torn from the tire (on a microscopic level), while it is adhering to the road surface. An excellent treadwear tire minimizes the amount of rubber being removed at the road surface; thus providing long tread life, but less road gripping traction.
http://forums.tdiclub.com/Tire Speed-Rating ("S","T","H","V","W","Y","Z")

A common Trade-Off for higher Speed-Rating is reduced Ride Comfort. An "S" Speed-Rated tire will give a more comfortable Ride compared to "H" Speed-Rated tire, and a "H" Speed-Rated tire will give a more comfortable Ride compared to a "Z" Speed-Rated tire. The Ride Comfort Characteristics can be attributed to the tire's Overall Stiffness. A tire capable of running at High Speeds requires a more stiff construction, in order to provide the necessary high speed stability & durability.
Tire Speed Rating Symbols:

S180km/h or 112mph T190km/h or 118mph U200km/h or 125mph H210km/h or 130mph V240km/h or 149mph W(ZR)270km/h or 168mph Y(ZR)300km/h or 186mph ZRAbove 300km/h or 186mph
A Z-Speed Rated tire without a Service Description means that the customer must consult the Tire Manufacturer to obtain the tire's Maximum Speed Capability.

As long as the load rating is correct and the speed rating you pick is not one you normally exceed then it is all personal choice. Do you have something like www.tirerack.com or www.1010tires.com that you can use to check user reviews?

Thanks for all the responses, one of the websites is not correct the 9090 and the 9000 both have the same tread pattern, hydro thingy and to me they look the same, and they both have a kerb protector

Will have a good read though once i hit lunch break....

I did ask at a local supplied yesterday and he said mine is only really fitted with these as the wheels where upgraded from new and AUDI just have a pile or wheel with tyres and as the same wheels fitted to 2.7t Petrol and all other models, they use one tyre for all within reason

But he was also told by a well informed customer that the 9090 have a higher load rating for the diesels as they are heavier engines and the torque puts more strain on the tyre... not sure will check think mine at lunch break, and a nice RS6 parked next too me...

For £20 it is not worth risking an accident, it is just now the 9090 is less available....

Muffin