Q Tire Speed Rating vs T Speed Rating at HWY Speeds (1 Viewer)

[KWLC250]

(TLDR) Are the differences negligible at real world highway speeds (65 -85 MPH)? Would you even given the difference a second thought? Or should I give more thought to the higher speed rated tire if my use case will be for tires that travels at higher speed more often than off road?

I'm looking to swap out the Michelin LTX trail tires that came on my LC250 to a larger tire with a more aggressive look. I live in Key West, FL. It's a small island in the Caribbean, 120 miles (3.5 hours drive) from the mainland. My car will almost certainly be 99% on road use due to my location and geography. I need a tire that can handle well in the wet for sure. Sunny day flooding is very common and obviously we have tropical weather/storm systems. While commuting on the island I don't exceed speeds of 40MPH. But it's pretty common to need to make the 3.5 hour drive to the mainland at highway speeds (~65MPH). And to traverse the Florida turnpike at constant speeds of 85MPH and higher for extended periods of time (example: I drove 7 hours each way to purchase my LC250).

Should I be concerned about a Q tire speed rating vs T tire speed rating?

Q is safely rated for 99mph and T is rated for 118mph. Using my example above; 85mph would be essentially 85% of the maximum "safe" speed of a Q rated tire, where as it would only be 72% of a T rated tire. Logically it sounds safer to travel at 72% of the maximum safe speed for extended periods of time vs 85%.

Are the differences negligible in real world scenarios, like the example I've given? I don't see myself exceeding 99mph in this rig. Or should I give more thought to higher speed rated tire if my use case will be for tire that travels at higher speed more often that off road?

 

[80t0ylc]

It’s not the speed that kills the tire, it’s the heat. Of course, the higher the speed, the higher the heat. But what also contributes is the tread pattern. The more aggressive, the tread, the more heat is generated. I don’t know what tires you’re looking at, but in your location, you’re probably considering an AT tread for your off road travels. A compromise for your vehicle use. That’s pretty moderate, but still generates more heat than a passenger car tread would. If I were in your shoes, I would go for the higher speed rated tire. Just a seventy year old person’s opinion.

 

[KWLC250]

It’s not the speed that kills the tire, it’s the heat. Of course, the higher the speed, the higher the heat. But what also contributes is the tread pattern. The more aggressive, the tread, the more heat is generated. I don’t know what tires you’re looking at, but in your location, you’re probably considering an AT tread for your off road travels. A compromise for your vehicle use. That’s pretty moderate, but still generates more heat than a passenger car tread would. If I were in your shoes, I would go for the higher speed rated tire. Just a seventy year old person’s opinion.

I was looking at the Nitto Ridge Grapplers, I like the aggressive look of the sidewalls and my wife's truck has the Ridge Grapplers so I'm already familiar with the ride characteristics (noise, comfort, etc.). Nitto offers a 285/70/R17 with a 116Q rating. My other choice would be the Toyo Open Country A/T III, which Toyo offers in a P285/70/R17 with a 117T rating. The Toyo also seems to edge out the Nitto in "Ride Comfort" and "Quiet Ride" (according Toyo's grading scale (Toyo also owns Nitto)).

 

[80t0ylc]

The last 20 yrs or so, Toyo has been my 1st choice in tires. I am currently running the AT lll size 31X10.50R15LT on my 2003 Ford Ranger FX4 pickup, which happens to be 'S' speed rated, according to Toyo's website. I can't speak for Nitto other than I've heard they're a decent and reliable tire. I'm currently running Toyo AT ll 315x75x16 that I can't seem to wear out before the recommended date code replacement on my '94 80 Series Land Cruiser. Also running Toyo M55 on my Ford F350 that I have the same "problem". IMHO Toyo tires are, in the same category as Michelin, some of the best made tires available. Toyo's are generally heavier than other same size tires. That tells me they're well built and able to stand up to the abuse that off road can dish out. I've had no issues with my AT lll. I think you'll be satisfied if you go with the Toyos.