[~JC~]

Drag Tires

CAN YOU HAVE THE BEST OF BOTH WORLDS?


In the '60s, if you wanted to go fast there wasn't much of a choice in tires. It was either full-blown race slicks or crappy stock bias-plies. Like everything in the performance aftermarket, tires have evolved over the decades, and today's race tires are stickier, softer, and far better than they used to be. Hell, today's street tires are better than most full-race tires from 30 years ago! With the introduction of the BFGoodrich Drag Radial roughly ten years ago, racers have been given the choice of a good compromise between streetability and ultimate traction.

Drag Radials (most of them anyway) allow you to drive the car on the street and still have traction that far surpasses a traditional “street” tire. BFGoodrich and Nitto have long had drag radials, but with the introduction of new tires from Mickey Thompson and M&H, the drag radial world has gotten even more serious. Each tire has its pros and cons, and that's what this story is about: explaining the differences between drag radials so that you can make the right choice for your combination and usage.

BFGoodrich Drag Radial
BFG had the first drag radial on the market, and is by far the most commonly used drag radial in heads-up racing. The BFG combines very good traction with a legitimate lifespan when used on the street. How good does this tire hook? The faster cars in the NMRA's BFG-sponsored Drag Radial class are in the 8.30s at 170mph, and in unlimited form, Dwayne Gutridge has run in the 7's on the 315/60-15 BFG! They won't last as long as the standard Comp T/A on the street, but a few thousand miles is not out of the question.

Under Pressure
We know of some racers that run pretty low tire pressures in their drag radials and sometimes it looks like the tires are flat. We asked Todd Steen from BFG what kind of pressures they recommend, “Well, people that do a 'John Force' burnout on the tires, we tell them somewhere between 16 and 18 pounds. The biggest thing that we tell them is that if they've been launching on another regular street tire, and let's say you've been launching at 4,500-5,000 rpm, do not go out there (on our tires) and air them down to 17-18 pounds and try to launch at that kind of rpm, because you're going to break something. They'll say, ‘no, no…’ but we tell them that's why they're signing the waiver. They'll come back with their axle in their hand, and they're proud of it! We say, ‘we told you!’ ”

Heating the Hides
We know of some racers that absolutely annihilate drag radials in the burnout box, but according to Steen, ”The compound itself works best at somewhere between 160 and 180 degrees. Now you'll see some of these racers doing these huge burnouts on our tires, and it's all for show. Once you get these tires up to 200 degrees, at that point you're just burning rubber. Now, it will take somebody some real time in test and tune to figure out how much of a burnout it takes to get the tire somewhere around 160-180. In unscientific terms, think about getting a stove up to that temperature and putting your hand on it - that's “warm to the touch” for sure. It doesn't flat-out burn you, but if someone was to put their hand on the tire after the burnout, you shouldn't be able to just rest your hand on it. If not, you're leaving grip on the table.”

Tire Additives?
We've heard that VHT and stuff like that work s well with drag radial compounds so we mentioned that to Steen also. He said, “we haven't found anywhere that VHT or any kind of traction compound has worked against us, but it is a street-legal tire, so normal pavement with no additives, it will still work like it's supposed to. For the most part, it should be the same, although it might take some adjustment to the tire pressure to get the most out of the tire. The biggest thing we stress is that because they're street legal, don't leave the track while you're still driving around on 16 or 18 pounds.”

Drag Tires in Street Tire Clothing
If drag radials can be run on the street can they be treated like street tires? We queried Steen. “Absolutely, they can be rotated, and run “against the grain.” You won't get extra traction. Preferably, you'll run them in the direction the tread is pointed, but it won't hurt them. As a matter of fact, there are three guys who swear to me that they got better traction when they turned them around. If it works on your car, it works on your car, but in theory it shouldn't make a difference.'

Mickey Thompson Drag Radial
Mickey Thompson set the tire world on fire with the introduction of their new ET Drag Radial, which at first glance looked to be incredibly sticky. Testing since the introduction has proven that the M/T is a very sticky tire, with traction that's not far removed from their ET Drag slicks. The M/T ET Drag radial is the spec tire for the PSCA's M/T Wild Street class. Unlike the other tires in question, these guys aren't recommended for the street, but they sure can hook! We spoke with drag radial expert Jason Moulton from M/T and got the inside scoop on these new sticky race radials.

Construction
Moulton would not get into specific technical details about the tire, but did say, “It's basically all about how the tire is laid-up and constructed. Our drag radial is a true radial-constructed tire that we would consider an ultra high-performance platform, and they are a DOT-approved tire. We offer two drag radials; we have an E.T Street radial and an E.T Drag radial. The E.T Drag radial is a street tire that is similar to our E.T Street bias ply tires, but we don't recommend it for normal highway use because it will wear out due to reduced tread depth and void in the tire”.

Tire Life
Moulton said, “It's really hard to say how long these tires will last in miles. A lot of it has to do with the type of vehicle the tires are put on and the weight of the vehicle. We haven't really had enough time to tell how long these things are going to last as an average, since most of the tires out there are mostly being used on the strip.” Based on our observation and Mickey Thompson's own verbiage that does not recommend them for street use, you're not going to get very good life out of these tires on the street. But that's the price you pay for the incredible traction they provide.

Compound Differences and Wet Traction
The M/T drag radial offers a ton of off-the-line-performance but are the tire compounds the same between the E.T. Drag and E.T. Street radials? And what about wet traction? Moulton explained, “With these types of tires there's not a big difference in compounds for the E.T Drag and E.T Street. The compounds are in the same family but they are a little different. As far as wet traction goes, the best thing I tell people is use common sense and be aware of what you have on the back of your car. These tires weren't meant for wet traction but if you use common sense under normal driving conditions those tires will get you home, pending any type of hurricane or anything like that.”

Slicks or Radials?
Will these radials hook as good as a full-boogie slick? We ran that by Moulton and he said, “Well again it's all application. I know for a fact that you can try to put these tires (drag radials) on some cars that are used to hooking with a bias ply [slick], and they work. But depending on how they are set up with weight and power levels, a slick might work better. When you get to high power levels there will be a technique to it, so yes this is true.“

Who Needs 'Em?
Since the drag radials are so good, we asked Mickey Thompson if there will still be a market for the E.T Street tire, and they explained, “The market for the E.T. Street drag radial is for the guy that wants more of a user-friendly tire as far as streetability. E.T. Street slicks are for high-horsepower, high-torque applications and manual transmission applications. The way a clutch car will 'hit' the basics of a radial tire, it will not absorb the horsepower like a bias ply tire will, which is good and bad. By not absorbing the power the radial has a potential to be quicker if it can get off the starting line without spinning.”

TO BE CONT.