Drag radials for street use...questions unanswered by the "experts".

[MoMo]

I just built a really powerful 427 big block for my Corvette. I am dismayed that the 255/60SR-15's are woefully inadequate. At just 1/4th of the way into the primaries, my son tells me I'm laying down serious rubber for a good 30 feet. There's no way my "street-rated" tires are anywhere near adequate or safe on this car. So I wrote to The Tire Rack to ask some basic questions about drag radials. As far as I know, there are two manufacturers producing drag radials, BF Goodrich, and Nitto. BFG's drag radials have been the ONLY tires that friends of mine in extremely powerful muscle cars have been able to successfully run on the street and the strip. But they tend to propel a car to well beyond an S-rated tire's safe speed capabilities. So I had to ask the experts. 1. You can get a drag radial in sizes that no longer have speed tires made. For example, you can get a 275/50R-15 drag radial at both BFG and Nitto. But the closest speed rated front runner is only 24" in height in that wheel size. Expert's answer: Sorry, there are no speed rated tires made in the diameter that I desire. Plus, I was told not to run a different tread pattern on the front and rear tires. 2. Based on that answer, I asked where I could get an identical tread in a front tire? The last tire BFG made with anywhere near the same tread pattern for the fronts was the now-discontinued Comp T/A R-1. And absolutely no one makes the gatorback tread pattern to match that of the Nitto drag radial in 15" with a diameter of at least 26". So I asked them how exactly I was supposed to get an identical tread pattern for the front tires. Expert answer: No answer. They ignored me. I must've stumped the chumps. 3. The drag radials are street legal. Another question I had asked is how much the drag radials can be run on the street or highway safely, and up to what top speed are they rated. Expert answer: Although they are street legal, do not drive them extensively on the street unless the car is stopped periodically to let the tires cool back down. Catastrophic tire/car damage could result. 4. Based on that answer, I asked the experts how much they CAN be safely driven before I need to pull over and cool down the tires, and for how long. Expert answer: No answer. I'll bet I'm really pissing these guys off by now. 5. So I wrote to Nitto. I asked them the same questions. They say their NT555R drag radial is designed to last up to 15,000 miles of normal street driving, and that their tires are completely safe for the street. I asked them how safe? What about heat cycling and cooling down the tires? How high is their street rating? Expert answer: No answer. I'm not even sure if these guys monitor their tech lines. Basically, what's a guy to do? Buy 17" wheels and kiss their pristine original 15" factory wheels goodbye? Only to have the tire manufacturers continue to cater to mostly foreign cars and their wierd tire sizes in a few short years, forcing us to then sell our pristine 17" wheels and upgrade to (gack) 20" wheels? Is there an expert that can answer my questions above? Thank you.

[69ttop502]

Boy did you nail this one on the head Momo. I am in the same boat with my soon to be completed 600 horse 502 in my 69. I just don't know what I am going to do. I too do not want to get rid of my 15's. I would look into some of the vintage racing and autocross tires like the Goodyear Blue Streaks and dunlops. I haven't really researched them yet but that will probably be what I end up doing as I will never drive my car in the rain or wet. I know Carrol Shelby has a website that carry the Blue Streaks as Chuck Harmon gave it to me but I don't have it here. I will be watching this thread very closely. Bill.

[Luke@tirerack]

I do not know who sent you the e-mail but here are some facts from my drag car which runs 10.20's @ 140+ on drag radials....

tread patterns are there for only 1 reason ... to evacuate water and drag radials don't even attempt to do that (they absolutely suck in the wet)

speed rated tires are available to match the 275/50-15 ... why not the 225/60VR15 BFG touring T/A and there are many options if you use a 28" diameter like I use on my car

I have driven my car for several hours non-stop (5+ hours with a several gas stops) but nowhere near enough stop time for the tires to cool down

I have driven and raced on the latest set for over 5,000 miles and still have them on the car.

Hope this helps
Luke

[No Go]

Not trying to be offensive, but I think you are being a bit anal:)

A relative has run 275/60-15 DR's on the back of his 461/M20 Caprice for over 3 years. It was driven from Iowa to Seatle with no problems. He just paired it up with a Goodyear Eagle GA in the front.

I have Nitto Extreme 555R II roadracing tires on my 96. So far 4000 street miles with some 250 track miles. I drove it from Nebraska to Alabama and back straight thru-15 hours each way. No problems.

Tires are pretty durable. When you run it out of tread, lousy balance, have nails, low tire pressure, etc then I would be concerned.

Our niche is so small, I'm quite thankful that manufacturers actually offer these tires-imagine a world with no soft DR's!

Bottomline, I don't think the template of requirements manufacturers put out there are realistic for very high performance tires... ;)

[MoMo]

Maybe I am. But with $30,000+ invested in my Corvette, do you blame me for trying to put a safe tire combo on my car?

Luke, thanks for your answers. Both of you have reinforced my confidence in running rear drag radials. You really should have a talk with your tech line people, because of the answers I was getting.

So, in your opinion, are these tires safe for very high top speeds, for say 100 miles at a time? Or should I stick to typical street driving with these, and utilize a road racing tire on different wheels for the road racing events, i.e. Pony Express 100 and Silver State Classic?

225/60VR-15's huh? Hmm, that's a size I haven't considered. Do they handle okay? Seems a little narrow, but on the flip side, perhaps they won't follow every road rut the way the 255/60-15's do. Also, the diameter on those are a little over an inch less than the 255's. But if that's the only way to get a speed rated tire on a 15" wheel, maybe I will have to go for the "hotwheel" look.

As far as the contention that our group is such a narrow group that we should feel lucky they even make tires in our size, I reject that. By narrowing the selection of the best speed rated tires to mostly Japanese cars that do not even closely require those kind of speed ratings, the tire manufacturers are clearly catoring to a niche that is nothing but trendy, and it's because of profit margins. It's not that the technology isn't available. A decade ago, we used to be able to buy a good 27" diameter 15" speed rated tire from a choice of manufacturers. "Supply and demand has shifted". Yes that's true, but it doesn't mean we don't need tires anymore.

The typical Corvette of most generations is capable of blowing away most imported cars in top speed, so what these imported cars need with megabuck 35 series tires that don't fit anything else, I couldn't begin to understand.

Anyway, that's my feelings on the subject. :skep:

[Luke@tirerack]

this is going to sound harsh ... and it should

Using a drag racing tire for a road race automatically qualifies you for a Darwin Award and hope you don't kill anybody else when you are carreening off the road into who knows what .... they are designed for sraight line use they have very little steering response and sidewall rigidity. Drag tires are designed to absorb the shock of launch with their soft sidewalls and road race tires are built to corner .... use the proper tire for the venue you wish to compete in .....


[Modified by Luke@tirerack, 1:46 PM 12/23/2002]

[MoMo]

Well that's why you're the expert and I'm the one asking you.
You know what they say, the only question that is a stupid question is the one that wasn't asked. We're not all experts like you guys.
:mad

I have not yet road raced, but is a venue that I want to get involved in. You yourself apparently hit 140 mph on a routine basis at the dragstrip, BUT that does not require handling. And that is not for an extended period of time.

The reason I ask is because Nitto claims their drag radial is suitable for road racing as well. So naturally, I was wondering. But nevermind.
In not so many words, you have answered my question.
For road racing events, get a different set of road racing specific tires and run those on a completely different set of wheels. And then use the drag radials for safer street use.

In less harsh terms, is that what you were trying to say?
:rolleyes:


[Modified by MoMo, 3:03 PM 12/23/2002]

[Luke@tirerack]

Actually, it sounds like you have been given incorrect info about drag tires and tread designs ....

#1.) drag tires have softer sidewalls to absorb the shock of launch .... by wrinkling up .... I'm sure you've seen picures of a drag car launching and the sidewalls are all twisted up ... they are designed with that in mind. Drag radials even though they are radials do wrinkle when used properly. The radial aspect of the tire enhances high speed, straight line stability. While on the other hand road race tires have a very stiff sidewall and are designed for steering response and feedback when cornering.

#2.) the only thing that tread designs do is channel and evacuate water from under the tread area and drag tires do not have enough tread depth or the correct design to perform that function anyway. The only reason drag radials have any tread at all is to make them DOT legal for use on ther street.

#3.) I agree and would not use an "S" rated tire on any of my cars that can and regularly exceed 125mph because it is just not safe. and the size that I recommended (225/60-15) was only a suggestion but, there are other options. What diameter can you use.

Sorry I was not trying to offend you I was just using humor to express my point at how bad of an idea it would be to use a drag tire in any event that has corners taken at speed

Luke
877-522-8473 ext. 362


[Modified by Luke@tirerack, 2:59 PM 12/23/2002]

[69ttop502]

Momo, I hope you don't mind if I jump in here but this is avery educational thread and thanks to Luke for the information. So Luke, in my situation with a 600+ horse 502 with a race ready suspension in a car that will never be driven in the rain and may be autocrossed eventually but mainly high performance street driving, what tire would you recommend. I don't care about tread life or cost within reason and the car will only see 3-4k miles a year, but I would like to stay near the 27 inch diameter with the 15 inch wheels. I have offset trailing arms in the rear so I can accomodate a wider tire. Do you have a Z rated tire that would work. Thanks, Bill.

[ML67]

Luke,

can't speak from personal experience, but i know of several people running drag radials w/ normal pressure (ie > 30 psi) w/ outstanding results on road race courses, solo events and general high performance street driving. I *have* driven one big block corvette (not mine -- a friend's) w/ 275/60-15 DR pumped up to ~ 35 psi and the handling was outstanding.

Not arguing w/ you, but there is more than anecdotal evidence to suggest BFG DR *can* be used for more than straight line performance.

take care,

Mark

[Chuck Harmon]

MoMo,

I am in the same boat. I really don't like the fact that I can't find anything but shorty tires with a speed rating worthy of the car. I also understand Luke's comments regarding drag tires not being the best choice for a sports car.

Like you said, I have given and continue to give serious thought to simply getting the Blue Streak vintage racing tires. I know that racing tires typically have very thin sidewalls to run cooler at high speed and are therefore very susceptible to sidewall damage while driving on public roads, "curb" scuffing in particular. I don't plan on parallel parking this car!

The G7 700-15 Blue Streaks are 26.7" tall, 8.6" wide and treaded. They come in a variety of grades of softness (stickiness). Race tire side walls are sometimes so thin the air bleeds through causing them to go flat within a day or two. But I think the Blue Streaks are a bit thicker but I believe they can also be run with tubes if needed. They are not state of the art tires for people racing for the big bucks. They are for cars to be driven simply for the pleasure of having fun at the track, like mine!

No, Blue Streaks don't have a DOT approval and "No" they don't include the road tax, BUT, they fit, they should stick just about as well as any tires offered for my ZO6, and they look the part! With my typical driving I would still expect to get 15-20K mileage from them. Yet even if the actual number is less, so what. They would still be close to $100 cheaper per tire than my ZO6 tires and they only last about 20K miles. Guys chew up Z tires very quickly if they race a lot and so it would be with my L88.

Can anyone give me a good reason why I should not use them? I am looking for good solid feedback.

Thanks,

Chuck

[Luke@tirerack]

here are some tire sizes / diamters to consider and some speed rated tires in those sizes

225/65-15=26.5
225/70-15=27.4
235/70-15=28.0
275/50-15=25.8
225/65-15=26.5
235/60-15=26.1

225/65VR15 PI P4000E
P225/70VR15 GY EAG RS-A
P235/70VR15 GY EAG RS-A
225/65ZR15 PI P4000E
235/60ZR15 PI P600
P275/50ZR15 HO R3S03 RADIAL
P245/50ZR15 HO R3S03 RADIAL

[Chuck Harmon]

Luke,

I understand Hoosier has just dropped out of the DOT tire business. I don't think the other tires you listed are in the same league regarding their compounds/stickiness. The Hoosier bias ply street TD would also have been a great tire. I think this is virtually the same design as the Blue Streaks I was speaking about.

Chuck

[MoMo]

Actually, those are some excellent suggestions, Luke. There are several there that would work. I was surprised to see a 275/50ZR-15. I'm also not familiar with that company. Are they available through the Tirerack?

The Blue Streaks may be a possibility for an extra set of Camaro wheels that I have. But I still have a set of the old 255/60VR-15 Comp T/A R-1's on them. They're bald, but probably okay for dry weather autocrossing or road racing.
I've got a good set of those too. I was thinking of running them on the front and a good set of 275/50ZR-15's on the rear. But those R-1's will last about as long as a bar of soap in a bathtub. Then I'll need a plan B.

Thanks Luke for those sizes.

[Chuck Harmon]

MoMo,

I think the HO 275/40ZR-15's are the Hoosier street series that Hoosier has discontinued. The new tire requirements imposed after all the Ford/Firestone brewhaha made low production tire runs impractical. If not the Blue Streaks, the BFG g force looks like a pretty good alternative. They have a 25.7 diam tire in the 17" wheel size. If so, I need to calculate how wide a wheel I could then go to stretch that carcas and make one firm footprint. I think an 18" wheel clears the parking brake bracket and end of leaf spring. The 17" wheel may be close.

I've got 18's on the rear of the Z now; but, I just can't quite bring myself to go that big on the C3. Something just doesn't look right. Yet, having the same tire size for both cars could make it convenient for track days. When I wear the Z tires down to the bars they are then perfect track depth. I could still use them on the L88 for track days.

Chuck

[The Money Pit]

I know that my tires are not speed rated,but for what it's worth I've run Kelly P295 50's for five years(this is my second set) and tracion is fairly good for a street tire. Of course I can smoke them if I want,but for the money I can't complain. With a 3.70 rear,my top end is only 130mph anyway,and with the roads around here,130mph doesn't happen very often,or for very long. I must mention that on hydroplaning,anything more than damp pavement,too much throttle and you will be doing dougnuts,like it or not.
By the way these Kelly tires are good for around 40,000 miles a set. :chevy