The speed rating system has changed over the years. The "Z" doesn't mean what it used to. Look at the info below for the correct speed rating determinations. The items in BOLD are what really determines the maximum speed of the tire.: 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.
Here is some more fun stuff. 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: L 75 mph 120 km/h Off-Road & Light Truck Tires M 81 mph 130 km/h N 87 mph 140km/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
So I still cannot run W rated tyres but can run Zs as long as they don't have a secondary rating. I don't know who to be more p!55ed off with, the tyre companies fore not making the tyres or Ferrari for making such stupid sized wheel!
Al, you definetly look at going down the 360 wheels route. I cannot because I have knock-ons and a conversion is big big money
Do you have a real, operational need for W, or higher, speed rated tires? (I repeat) The stock OEM TR tire is V speed rated.
My only concern is that on a car with a top speed of 186mph, the insurance company may, in the worst case scenario, refuse to pay out if it only had tyres on rated at 168mph, regardless of what speed might be involved. I don't like leaving potential loop holes. I will chase my insurance company up again. al
By this logic, no stock TR could have ever been insured properly in the UK -- I'm sure that that has not been the case. Unless you have a real need to operate at those uber-high speeds, I don't see how using the OEM speed rated V (or higher) tire can be a problem -- i.e., the insurance company should already be aware that stock TR use V rated tires. JMO.
Yay! Insurance company confirmed that I can use W rated tires But what does this mean from Wikipedia? "The tire code for the U.S. version of the vehicle had Goodyear 225/50 VR 16 and 255/50 VR 16 for the rear tires, whilst the tire codes for the international version had Michelin TRX 240/45 VR 415 for the front tires and TRX 280/45 VR 415 for the rear tires" I am presuming the "international version" is the hated "metric" option, but are the actual wheels that much bigger that they can take 280/45s? Could I in practice go wider than 265/45? Nothing's ever simple is it.
I think that your insurance company would never look at the speed rating after a loss and I would me more concerned of the fact that you were going a crazy speed. Unless you got something in writing its hear say anyway. Your over thinking this. Even if your tires are balder than bald and you have a blow out and loose it in a divider they would cover everything but the tire. At what point did you think you would not be covered. Are we talking about track coverage. R
The "international version" is UK Metric wheels, which use the Michelin TRX's. Mine is a ex-Swiss car that uses "normal" tyres, i.e the 225/50/16 & 255/50/16. You can't put TRX's on non metric wheels.
I think the short answer is "yes". If you look up the recommended wheel width for 255/50-16 tires, it's usually given as 7"-9" (so the 10" TR rear wheel is really too wide). If you can find a 16" tire wider than 265, please post the information.
Right now ANY tires will do Steve! My concern has only ever been not giving the insurance Co ANY loophole should the worse occur.
Well, I'm sorted for this year anyway. I have just received delivery of a pair of 255/50/16 Z Goodyear Eagle F1s (which match the front), with 5mm tread still on them for the grand sum of £145 for the pair. Hopefully they should do the job until we can find a better source
Just received delivery of what might actually be the last BF Goodrich 255 50ZR 60 in the world! Got it from www.treadepot.com. I only needed one and miraculously, they had it. Now I have to hope I don't sustain any more unrepairable punctures.
What is the production date of the tire? More info at: http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=11
Per the website and a phone call to BF Goodrich the 255/50 16 size will be available in April. Looking at the specs for the tires it states the rim width range for the tires is 7 - 9 inches. Is that a problem for a TR with the stock rear rims that are 10" wide? Thoughts?
I have them on my TR and I don't really care for the look. From the rim to the edge of the tread area the sidewalls curve inwards, making them look a little narrow for the wheel. A 275/50 would look much better (and correct). From a safety stand point the 255/50's are fine. From a traction standpoint I don't like them. The compound is 340, TOO HARD, and should be closer to 180 for the big-ass on this car.
No argument at all that the rear tire should be wider just to balance the heft of the TR rear coachwork, but make mine 275/45-16 or 285/45-16 -- a TR doesn't need a taller effective gear ratio