Anyone have any firsthand experience with the Nankang SP-7? Hate running the foreign-made tire and the modern (goofy) tread pattern but, it's all I can find in this size above a T-rating. These can be had pretty inexpensively online and Walmart. Maybe they're cheap for a reason, other than from being made offshore? Brand: Nankang Part Number: NK-24370103 Name: SP-7 Performance X/P Load: 107 Speed: H UTQG: 420 AA A Warranty: 40,000 Mile http://www.discountedwheelwarehouse.com/Discount_Tires.cfm?pn=NK-24370103&pID=83596
I've had good luck with Coopers and just stick with them so I wouldn't even look at these. My 2 cents.
If I'm deciphering that correctly, your question is why you require and H-rated tire, yes? T-rated is for up to approximately 118 mph, where H-rated is 130 mph.
Sorry for the typo. T rated tires are higher speed rated than the a S rated tires that are on 95% of the cars that we all have in our garages. How are you using your car that you need the H rated tires?
L 75 mph 120 km/h Off-Road & Light Truck Tires M 81 mph 130 km/h Temporary Spare Tires N 87 mph 140km/h 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 I had this problem. My car was primarily street driven. But I'd go to the track once or twice a year to have some fun. Then it was pointed out to me that my front tires were S rated, 112 mph. And that's where I was at the top end of the 1/4 mile. Yikes. Too close for me. I swapped them out for a set of H rated right away.
Exceeding the speed rating for 1 or 2 seconds a year is NOT a reason to change speed rating of your tires. If you were going to run the Silver State Classic, then we should talk about speed ratings. The speed rating has to do with heat buildup in the tire as a "steady state" condition - and you'll never see that in the 1/4 mile. It also makes some other assumption (i.e. the ambient temperature is at the high end of the temperature rating, you'll be doing some cornering, and so on). If you hit 120 MPH in the 1/4 mile then apply the brakes, a tire rated for 118 MPH is totally fine. Or 112 MPH even. If you have tire problems, it won't be because of the speed rating. -Bob C. p.s. One other reminder - NEVER put never-seize or any lubricant on the back of your rim, on the mating surface to the hub. Please. Never. That must be a dry contact surface.
X2, and as most guys do at the track, they inflate their front tires up to the max to reduce rolling resistance which also cuts down on the heat built up in a rolling tire. A radial tire heats up from the sidewall deflection (radial bulge) at the contact patch.
Better safe than sorry. For $200 I wasn't going to take a chance on blowing a tire and wrecking the tire and possibly someone else. Not to mention me.
When I first got my Buick I bought Dunlop GT Qualifiers. They were S rated. Every time I went to my brother's house, 30 miles away, the tread would separate. Yes, I did 120 for maybe a minute of so. I didn't think the S rating was any big deal. After breaking 3 tires I quit Dunlop's tires and went with BF Goodrich tires, S rated. It never happened again. Were the Dunlop tires that cheaply made? Just my experience(s).
John, just curious what the Dunlops were inflated to. Any tire that is subjected to those kind of speeds for, in your case, up to 2 minutes, should be inflated to the maximum inflation pressure listed on the sidewall. Many are misinformed on the subject of tire inflation, and to add to that, the maximum inflation pressures have been going up for the last 8-10 years. The tire placard information in your owners manual, or door, goes right out the window when you go to a newer tire. Tires manufactured today can have much higher maximum inflation pressures listed on the sidewall. As an example, the Cooper Cobras on my GS have a maximum inflation of 44 psi. The Yokohama tires on my 98 Riviera are 51 psi tires. The tire pressure placard for my 98 lists 30 psi front and rear for an OEM equipped tire with a 35 psi max inflation pressure. The Yokohama tires at 30 psi are very under inflated and the ride and handling are very noticeably worse. I run them at 43 psi, and you would think they would ride hard, but they do not, quite the opposite. My Coopers on the GS are inflated to 39 psi. The car rides great. It's really important to actually look at the sidewall of any tire you have on the car, especially if it is a new tire. In general, you should run a tire at 85-90% of the max inflation pressure listed on the sidewall. If you intend to subject any tire to sustained speeds above 100 MPH, then I would inflate it to the max pressure cold before hand, especially in hot weather. Like I stated previously, radial tires have a bulge at the contact patch. Think about that bulge propagating along the entire tire as it rolls at high speed. That is what builds up heat in a tire. Higher speed tires are built to deal with that heat and dissipate it. They still need to be inflated properly. Something to think about.
A little late to the thread but Maxton were about the only H rated tires in 15's that would fit a muscle car when I was looking a few years back. Turned out I didn't need them for running the Maxton Mile in my class but I was about ready to pull the trigger if I did. SUV/LT but our cars are pretty much that when compared to some of the newer vehicles. http://www.maxxis.com/catalog/tire-8-104-marauder-ma-s1
Exactly. They don't have a time at speed duration coupled to that max speed rating. How often do I run that fast? Depends how I'm feeling in the moment and where I'm at, never kept track of it. I consider the speed rating more like any insurance policy you purchase.
Hey Larry, In response to your question about how much about "How much air pressure did I run in the Dunlops?" That was more than 20 years ago, but I always run the maximum air pressure. I believe it was 35 PSI as are my BF Goodrich's right now. Check this out... My alignment shop, which is one of the oldest in West Palm Beach, recommended that I run 41 PSI in my front tires, 35 in the back tires. My car drives GREAT that way. I've never had any issue even driving the 1,100 miles to Bowling Green. Food for thought....................
John, my point is that new tires may in fact be different than what originally came on your car. That means the OEM tire pressure recommendations no longer apply. Tires made today commonly have 44 and 51 psi maximum inflation pressures.
