I understand how they required new ratings for tires etc.
I have a c4 that can top 205 mph. I just sold my pirelli p zero rossos and went with Nitto Invos. The front tires have a W rating The rears are Y.
the 168 W rating, is this a sustained speed rating say for long distance cruising on the autobahn? Can you increase tire pressure and safely obtain higher speeds? This bothers be because this means I can't even top 4th gear on the highway with these tires
Luke or any Tire professional care to shed some light please.
I seriously doubt that the Invo's are designed for SUSTAINED all-out speed. An email inquiry to Nitto should get you the info you seek. In as far as tire pressure, I would not think it prudent to increase tire pressure beyond the recommendations embossed on the tire. Those tire pressures are calibrated based on extensive testing and are laid-out to you as a guide for safety.
Some years ago, you may recall that Firestone was called on the carpet due to factory supplied tires to Ford SUV's whereby there were traffic fatalities and roll-overs due to tires which were unsuitably designed for the intended purpose. Firestone settled that suit DEEP into the $M's. Tire manufacturers are required to be accountable for tire failure based on unsuitability for it's INTENDED PURPOSE. Therefor, you can be assured that whatever Nitto tells you will be the correct answer.
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
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.
Some years ago, you may recall that Firestone was called on the carpet due to factory supplied tires to Ford SUV's whereby there were traffic fatalities and roll-overs due to tires which were unsuitably designed for the intended purpose. Firestone settled that suit DEEP into the $M's. Tire manufacturers are required to be accountable for tire failure based on unsuitability for it's INTENDED PURPOSE.
the Firestone/Ford issue was caused by Ford recommending 26 psi inflation pressures to reduce the possibility of roll overs while cornering. Firestone was at fault for signing off on that recommendation to keep Ford happy
I understand how they required new ratings for tires etc.
I have a c4 that can top 205 mph. I just sold my pirelli p zero rossos and went with Nitto Invos. The front tires have a W rating The rears are Y.
the 168 W rating, is this a sustained speed rating say for long distance cruising on the autobahn? Can you increase tire pressure and safely obtain higher speeds? This bothers be because this means I can't even top 4th gear on the highway with these tires
Luke or any Tire professional care to shed some light please.
mixing speed rating is a bad idea and inflation pressure adjustments can not correct it
and if you are actually going over 170 on the highway DO NOT POST IN OT or the Road Race forum without flame proof underwear
Luke you sold me the pirelli P zero rossos I just removed from my wheels. I went with invos because 1. the tread looks amazing and it has a beautiful sidewall for tire dressing 2. The price is much much better than the rossos. 3. The sizes I wanted were available (315/25/19 and 265/30/19).
I didnt want to mix speed ratings but running a 10 and 11.5 inch wheel those are the 2 sizes I want that give me the diameter I seek with matching overall height. The 265s are w while the 315s are Y.
What I am really asking is are the ratings set while running the maximum load on the tire? It makes me curious because My car weighs 3275 and is well under the max load capacity. What I was asking about tire pressure was not beyond the specs, which I'm guessing 51 psi but say if the reccomendation was 35 psi I was suggesting running 38-40 if I planned to max out the car.
In all, this means I cannot even briefly surpass 168 mph without blowing up the tire ?
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
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.
Need Clarification.. W / Y speed rating ??
The rears are Y.
