Landracing Forum
Bonneville Salt Flats Discussion => SCTA Rule Questions => Topic started by: revolutionary on July 06, 2010, 01:46:15 PM
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Does anyone (DW maybe?) know if there is a specific ruling as to the rated speed for drag radials? Looking closely at the rulebook I see various ratings for OEM - vr/ZR rated tires but the drag radials such as Mickey Thompsons don't have a speed rated letter i.e. 255/75R15. They are listed under their 'Strip' section on Mickey Thompson's website and the description reads "this D.O.T. approved street legal drag radial will get your car down the track in record time and drive you home with sure handling and an excellent ride" indicating it is a tire made specifically for racing that happens to be street legal. I would read that as being within the "Special tires for racing as designed by the manufacturer" rule and would certainly feel safe running them at 240 but my opinion doesn't realy matter here. I'd like to know for sure if there has been such a ruling on these.
Thanks
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I am not sure about the use of drag radials for LSR. You may want to contact either Lee Kennedy or Kiwi Steve Davies, both are in the rulebook. Maybe some one else can jump in here.
DW
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not recommended for motorcycles :roll:
Kent
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I recall being told MT Drag Radial Racing Tires approved up to 225mph or 250mph... Since all I need is 215mph, I can't full rememeber which was the max mph 225 or 250.
The same MT or Goodyear drag race radial slick (non street legal) is Ok to 250 from what I read... I would think the street legal version may be as good or better for LSR as it "seems" to have a slightly stiffer side wall...
I ran them on the Vicky at Maxton and they felt more loosey gooesy on the rear, so I went back to V rated BFG G Force Sports (extreme summer tires) and felt very stable...
May be I did not have enough air in the MT Drag Radials for LSR ???
Charles
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Last year I inspected a Toyota Celica that we had to limit the speed on because there was zero supporting info on the speed rating for the M/T drag radials that were on the front of the car. The decision at that time was that we would need to see actual M/T documation stating a speed rating before the speed limit would be lifted. Unfortunatley, "I heard they were rated..." won't get you through tech. Bring a piece of paper with you from the tire manufacturer that says exactly what they're rated to.
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This may be a dumb question but doesn't "DOT approved" mean that they have a rating and it is branded on the tire?
Just went and looked at the MT web site. The only ones advertised as DOT approved are the ET Drag motorcycle radial, the ET street, the ET street radial and the ET street radial II. None of the 6 "ET Drag" labeled tires are DOT approved and the ET front has a disclaimer saying it is not approved for land speed use.
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Waiting to hear back from Kiwi Steve for the official word
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Waiting to hear back from Kiwi Steve for the official word
Please let us know what he said.
Thanks
Charles
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Looks like we'll be able to at least give them a try. We'll bring backup tires in case but really want to try to get these approved permanantly for future racers.
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I still think the safest thing to do would be to contact M/T for speed rating info. Are you just going to run 'em until they fail and then we'll know their speed rating?
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Whats a drag radial look like with 60 PSI in them on an 8 or 10" rim? Just courious......
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"Are you just going to run 'em until they fail and then we'll know their speed rating?"
Only if they fail in the lights.
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I got a reply back from Steve that said we could run them on a trial basis with inspections between progressively faster runs. That is exactly the kind of response that I was looking for and shows an openess to new ideas.
As far as running them til they fail - lets hope that never happens.
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I STILL don't understand why you haven't contacted M/T.
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I STILL don't understand why you haven't contacted M/T.
I have in the past spoken to MT... "for liability reasons" they will not even answer a question once you say Land Speed Racing as it pertains to those tires. They say those tires are for short distance drag racing at high speeds.
I then reworded my question,, I asked OK,,, "on the drag strip" would the tires be OK for 225 to 250 MPH.... the answer was yes because they are only at top speed for a few seconds.
So no real good answer.
Just relaying my experience calling MT...
Hope whomever calls again gets a more decisive answer than I did.
Charles
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They say those tires are for short distance drag racing at high speeds.
That's all I needed to hear...er um, see.
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They won't release results of destructive testing that shows what the true limits are. Same story with nascar tires. they have different compounds for different tracks designed for different speeds and loads but they are not differentiated in the scta rule book and talking with the tire reps that I have they dont have a good answer as to what the maximum speed rating is for X tire. Only that 'those' ones were designed for Martinsville or Daytona or whatever. But people still use them for LSR. Front runners when you talk with a tire rep are not designed for land speed racing. But people still use them for LSR. The only tires that are designed for land speed racing are...land speed racing tires. The question is at what point do you need them vs. X tire? 10mph? 100mph? 200mph? 300mph? I don't have $2000 for a set of tires and I don't plan on going 250mph so I'm in a tire limbo land and trying to see what the options are.
Drag radials were initially design for short distance drag racing at high speeds, yes. But you know, Viagra was developed for high blood pressure and angina, and I hear it has more than the one use...
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While I agree with the general jist of what you've said, we've allowed the use of front runners because they've widely been proven to be a reliable LSR tire to certain extents whereas drag radials have not. So it seems to me that you're exploring this avenue because of tire availability and possible tire sizing issues. Many drag radials are smaller diameter for use on normal passenger cars or even FWD cars. Are you going to be running a FWD car that needs a shorter tire to fit? If not, what is driving you to want to use drag radials?
I may be totally wrong here but I'm ASSuming that you're running a FWD vehicle and you're assuming (well I'm assuming that you're assuming) that you can't get an appropriate LSR to fit your car. I'd have to point out that both the Hondata cars are using small diameter LSR tires and the RSX has gone over 200 mph multiple times without issue.
Anyways, sorry for all the hassle. Just hate to see someone be a tire failure test dummy if the don't need to be, ya know?
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I'm not trying to over simplify this but the 2010 SCTA rule book on pg. 19 under 2F clearly states what tires are required.
Goodyear does indeed make an LSR tire that is based on the "front runner" drag tire.
I myself personally would never run a drag radial.
Tire makers will never release "absolute" tire information (as you have found out) because racers run in so many different configurations. ie total weight, down force, track surface conditions, air pressure, open to air or enclosed wheel well, temperature, etc.....
If the record in your class in under 200 mph I don't understand the issue, sorry.
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Are you going to be running a FWD car that needs a shorter tire to fit? If not, what is driving you to want to use drag radials?
96 firebird B/FALT rwd running on a 237 record. Miles away from the speeds that he ^^^ ran (incredible BTW!). I don't have anywhere near the beans for that but I think I have a pretty fair shot at getting near the 237 mark. I'd like to run the drag radials because A: I have them and they fit (275/50r15 which is 26 tall x 10.5 tread), B: as mentioned before I don't have $2000 for a set of Goodyear LSR tires C: I have access to NASCAR superspeedway tires but they are 28 x 10.5 which screws up my whole combo because I have to jack up the rear end to make them not rub D:You said yourself that front runners have proven to be a reliable land speed racing tires whereas drag radials have not - how would you plan to prove their reliability then? How did front runners prove their reliability? E: pg 19 under 2F clearly states that over 200mph what is required is "special tires for racing as designated by the manufacturer" - what it does not state is for what type of racing they were designated. i.e front runners are designed for drag racing and not land speed racing yet they are used quite often with very little issue. Actually, the Hoosier rep told me specifically NOT to use their front runners for land speed racing because he did not think they would hold up.
Dyno you said you would never run a drag radial. Even on a car going 70mph? Why not?
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Several faster (180 to 225 mph) cars at Maxton use M/T and BFG Drag Radials.
I guess since the 10" width helps with traction. I watched for 2 years Roadsters and Full Bodied Cars go down the track at those speeds with drag radials, I then asked the drivers about the tire etc... I checked with the chief tech and was told all OK to use them.
I bought a pair for the rear of my 1933 Ford Vicky. 1. yes they hooked up better than my street tires, I only hazed the tires for a few hundred feet. 2. The car went a bit faster 3. They felt unstable to me above 150, I may have had to low tire pressure.
I switched to BFG G Force Sport Z rated tires,,, a little less first gear traction, better stability and I went faster,, faster was because the car handled better....They are low profile Z rated tires and did quite well.
If I use the drag radials for LSR on the Stude,,, I will air them up more...and see how that works
Charles
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If not mistaken drag radials are designed to run a fairly low pressure by LSR standards. What does your combination look like with 60 psi in them? I'll bet they are not flat. Bonneville is not a place where you are allowed to run to a tire with "drag race" air pressure. The use of wide rim/tire combination usually ends with you getting to keen view at ALL of the race course during your run (as you spinning around)
Goodyear lists a 26" diameter front runner which meets your diameter spec. (looked up both on the Roger Krause website) You would need a narrower rim which for the most part has been much better for LSR use.
All kind of motor sports have inherant costs and one of LSR's is tire/rim combos. At least most of ours lasts for many years.............Good Luck
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But the point is well taken. How did it become known that Goodyear Frontrunners were safe to use. How did it come about that Dunlop Vintage race tires were accepted. People just started running them and nothing bad happened. That I know about, anyway. So it seems that a test session has been approved to see how the Drag Radials work in real life. Works for me. We will never know as long as we are relying on debate. MT has no good reason to reply with a speed rating for the tire. As almost everyone who has tried to get something in writing about using tires for speed trials knows. It don't happen
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Rich,
Here is what an old memory remembers. Back sometime in the 1980's there were no tires available. Everyone was running on old tires. Old indy tires, old MT LSR tires etc, because no one was building any LSR Tires.
Gail Banks had a door car he thought would go 300. He had the pull to get Goodyear to approve Front runners to a speed of 300. That is what I remember on the subject of front runners.
Tom G.
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That may well be. But in my memory I remember having Front Runners on my coup in the 70s. And I sure wasn't breaking new ground. So how exactally it came about that Front Runners became accepted, I don't know. But it wasn't Gale Banks in the 80s.
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Rich,
Sorry, I should have clarified that is how they got a rating good for 300 mph for Gail's car.
Tom G.
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Why re-invent the wheel er tire? Approved tires already exist and are easily obtainable.
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Why not?
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Different strokes I guess.
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Why re-invent the wheel er tire? Approved tires already exist and are easily obtainable.
Why try to progress? Why try to set new records? Maybe I should just buy a crate engine and bracket race it instead of trying to push our sport...Rich Fox took my point that there must be a way to figure out what really is safe or not. I have received approval to make progressively faster runs with inspections between runs which is the best way to do this. I guess you just don't like change. Keep the status quo. It's not like I'm doing something crazy like driving a stock bodied car 300mph;) See you on the salt.
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pg 19 under 2F clearly states that over 200mph what is required is "special tires for racing as designated by the manufacturer" - what it does not state is for what type of racing they were designated
What type of racing? How about land speed racing?
front runners are designed for drag racing and not land speed racing
Goodyear does indeed make an LSR tire that is based on the "front runner" drag tire.
... which by the way is what you'll find on most LSR cars using Goodyear "Front Runners".
You using a potentially unacceptable tire simply because you don't want to buy the correct tires isn't progressing our sport IMO. Sounds to me like you're being cheap and want to work around the rules but you're disguising this by getting philosophical.
But hey, you already got approval so I guess we'll just have to wait and see what happens. I will say that I agree with Dynoroom and that I would not use a 10.5" wide winkle wall soft compound drag tire that is only designed to be used a quarter mile at a time.
See ya in inspection.
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Are you going to be running a FWD car that needs a shorter tire to fit? If not, what is driving you to want to use drag radials?
96 firebird B/FALT rwd running on a 237 record. Miles away from the speeds that he ^^^ ran (incredible BTW!). I don't have anywhere near the beans for that but I think I have a pretty fair shot at getting near the 237 mark. I'd like to run the drag radials because A: I have them and they fit (275/50r15 which is 26 tall x 10.5 tread), B: as mentioned before I don't have $2000 for a set of Goodyear LSR tires C: I have access to NASCAR superspeedway tires but they are 28 x 10.5 which screws up my whole combo because I have to jack up the rear end to make them not rub D:You said yourself that front runners have proven to be a reliable land speed racing tires whereas drag radials have not - how would you plan to prove their reliability then? How did front runners prove their reliability? E: pg 19 under 2F clearly states that over 200mph what is required is "special tires for racing as designated by the manufacturer" - what it does not state is for what type of racing they were designated. i.e front runners are designed for drag racing and not land speed racing yet they are used quite often with very little issue. Actually, the Hoosier rep told me specifically NOT to use their front runners for land speed racing because he did not think they would hold up.
Dyno you said you would never run a drag radial. Even on a car going 70mph? Why not?
We all know we're not talking freeway speeds here or the question wouldn't have come up.
But the main reasons for me not to run drag radials is because "generally speaking" LSR cars that run on the salt either weigh quite a bit more (mine do) or have more down force than drag cars that run the type of tire you propose. The side wall construction is designed to "give" a bit with lower air pressures to aid traction on the drag strip. This sidewall flex in a heavy car could be an issue at speed on a surface we already know to be somewhat slick. I'm not saying they can't spin the speed you need to go for the amount of "time" they need to be there (but we don't know do we) just saying you might not like some of the "other" things that happen along the way. But if Steve says you can run 'em great. I have no problem learning from others.
Stop by at Speed Week and let me know how your doing with this test.
Good Luck with your project. :cheers:
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Mike makes my point. I like to look at things as a "Risk to Reward ratio" Get up in the morning. "Should I rob a bank today?" Risk- Get caught, go to jail, lose everything. Reward- couple grand. Not a good ratio. No bank today. Here revolutionary is willing to risk some time and money. The reward may be an inexpensive, readily available tire that works for some of us. Seems a fair trade off. No risk to me and a possable reward. Today there are lots of tires around and they are not as much of a consideration as they once were. But who knows when that will change. If there was a useful tire you could order from Summit, what is the down side?
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The last line in Mike's signature says it all.
Mike
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I started this post a number of times over the last few days, but never finished. I don't post much, but feel compelled to address this topic.
At present there is NO public data on running a drag radial to failure EXCEPT the design engineers at the manufacturers. They will NOT release that information because of liabilities. You want to run these DOT/Drag tires at MY venue and go on your head when it fails at the big end, I don't get it.......and I don't want to see it. There are smarter ways of pushing the envelope these days.
For those that don't know me, I ran a Merkur F/PS during the 90's ane early 2000's with a reasonable amount of success. I have moved on to do my present liner which hopefully will be done next summer.
I also worked with Ford on the Hydrogen Fuel Cell Fusion 999. We went 207 MPH with an electric car, with no batteries.
My Merk was only around 700 HP, and 4200 pounds, wet ready to race. (pretty heavy for a 102" wheelbase car.)
I did not have unexpected major traction problems.
I didn't always listen to the "wise, old, left coast experts" and even ran 28" Talladega tires one year till I spun around 180something
and almost took out the lights. Switched to GY front runners and made a record knocking on the door of 200.
For a number of years I was lucky enough to have Michelin/BF Goodrich as a sponsor. and I worked very closely with a Michelin engineer who even would attend the Maxton meets with me as long as I didn't tell anyone who he was.
Pointedly we had a really good trusting relationship.
When I asked about trying drag radials, the immediate answer was no. They were mostly concerned with vehicle weight, heat and high speed stability. They had all the info on my car and recommended what they "knew" would be safe.
I don't know how to engineer a tire, but do know how to listen to an expert. The guy that designs these things is the expert.
The typical "Tire Company Representative" is not the engineer that designs and validates the product and is not qualified to say ok to run them.
With all due respect to the SCTA Tech guy that said it is ok to run them, I think it is the wrong thing to do. Especially when there are tires available to do the job.
It has nothing to do with being innovative or ground breaking, It is just plain stupid to run a tire designed for drag racing on a heavy car at speeds way over 200. I think a speed of 237 was mentioned.
I'm getting a little tired of the guys from other forms of racing or street cars not wanting to spend the money to make their car safe for very high speeds, coming around saying OH, my car is safe, the salesman told me it is so change the rules to let me run with the big dogs.
People get hurt in our sport, and I would hate to see it because someone insisted on defining the limits of a tire by trial and error.
There are certainly better ways of testing a tire.
Joe Law when he retired from LSR, had a tire testing machine that was "FOR SALE" he said real cheap. I'll bet no one stepped up. (even me), because there are now good tires for 200 to 300 MPH and higher. They are costly, but nobody said it was gonna be cheap..or easy
I'm with Mikey. I would not run a drag radial on the salt. No way, no how.
Actually I wouldn't run them on the street either even at 70 MPH.
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Rick, I'm glad you posted this. I too have been reading this thread with the same feelings you have. Anyone running a car 3 to 5 miles over 200 MPH needs to have lsr tires ( in my opinion). I found out the hard way.
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Are you going to be running a FWD car that needs a shorter tire to fit? If not, what is driving you to want to use drag radials?
96 firebird B/FALT rwd running on a 237 record. Miles away from the speeds that he ^^^ ran (incredible BTW!). I don't have anywhere near the beans for that but I think I have a pretty fair shot at getting near the 237 mark. I'd like to run the drag radials because A: I have them and they fit (275/50r15 which is 26 tall x 10.5 tread), B: as mentioned before I don't have $2000 for a set of Goodyear LSR tires C: I have access to NASCAR superspeedway tires but they are 28 x 10.5 which screws up my whole combo because I have to jack up the rear end to make them not rub D:You said yourself that front runners have proven to be a reliable land speed racing tires whereas drag radials have not - how would you plan to prove their reliability then? How did front runners prove their reliability? E: pg 19 under 2F clearly states that over 200mph what is required is "special tires for racing as designated by the manufacturer" - what it does not state is for what type of racing they were designated. i.e front runners are designed for drag racing and not land speed racing yet they are used quite often with very little issue. Actually, the Hoosier rep told me specifically NOT to use their front runners for land speed racing because he did not think they would hold up.
Dyno you said you would never run a drag radial. Even on a car going 70mph? Why not?
You might take a look at the goodyear eagle sports car GT series tires, thet have a 25'' and a 26.8'' 10.5'' wide in 15'' and 16'' rims
#1995 and #1996 .....$199 and $204 some of the faster sports cars are way up there in speed and they punish and torture their tires
way more than in LSR.
JL222
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Are there a few people here confusing "Frontrunners" with Goodyear "Landspeeds" that have Frontrunner moulded in the sidewall....but are of vastly different construction?
Personally, I don't see $500 as too much to pay for a tire the manufacturer rates to 300mph , and I'm driving a car at under 200 that will probably carry a wheel if it blows a tire, like, how much have you spent on your motor?....... If I was in a door car , i'd be saving my experimentation for things other than a cheaper line on tires, plenty of people have come unstuck and got hurt under 200.
And I'm scratching for every dollar.
Dr G
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Are there a few people here confusing "Frontrunners" with Goodyear "Landspeeds" that have Frontrunner moulded in the sidewall....but are of vastly different construction?
Dr G
Dr G,
Long before Goodyear ever made "Landspeed tires" some people used the standard dragracing frontrunner tires. As I remember Gail Banks got Goodyear to OK a speed rating of 300mph for the standard dragrace frontrunnner. This was when no new tires were available. Since that time Goodyear has come out with
"Landspeed Tires" which are far superior, to the dragrace tire.
Does this help to clear up any misunderstanding?
Tom G.
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Are there a few people here confusing "Frontrunners" with Goodyear "Landspeeds" that have Frontrunner moulded in the sidewall....but are of vastly different construction?
Dr G
Dr G,
Long before Goodyear ever made "Landspeed tires" some people used the standard dragracing frontrunner tires. As I remember Gail Banks got Goodyear to OK a speed rating of 300mph for the standard dragrace frontrunnner. This was when no new tires were available. Since that time Goodyear has come out with
"Landspeed Tires" which are far superior, to the dragrace tire.
Does this help to clear up any misunderstanding?
Tom G.
In 1994 we had a time of 288 mph with an exit speed of 279 [ trans gave up] using the non lsr Goodyear frontrunner tire, 10'' tire in rear same as Banks, we still have them up in storage and they don't have any CRACKS. We replaced them with a smaller tire as the top of the tire was slightly rubbing the inner fender. We also had times of 275 mph and 261 - 265 and 267 with no sign of problem.
JL222
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If Jon or someone else could get Denis Manning or Tom Burkland to chime in on this subject it would be wonderful. I talked to Denis for about a half hour at the gas up a couple years ago about LSR tires and the testing he had done. His knowledge of the causes of most tire LSR failure is very insightful. I've been racing for over 45 years in Sportscar, NASCAR, Motorcycles and LSR. I have done tire testing at Riverside and Ontario with Firestone and Goodyear and Denis still told me things about race tires I had not heard.
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In re: Doug Odom's idea of asking Tom Burkland or Denis Manning about tires -- I don't about Denis' on-line habits and so don't know if he reads this Forum. I do know that Tom does sometimes (maybe always?) does read here, but doesn't sign in or respond. I'll assume that's for his personal good reason, so will only encourage him (should he read this) to either contact me via email with a response to the query, or to contact Doug to give him the scoop.
Best I can do for now. . .
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Well we had a great time on the salt this year. Thanks Nathan for the good rookie orientation. Mike Spacek(?) checked our tires after every run and was extremely helpful in making sure that we were as safe as possible. We progressively ran the tires up to 186 in the 1/4 and in debating whether to keep incrementally moving up 5mph at a time I figured we only had one or two runs left (head gasket pushing water) so we swapped over to a set of 28 x 4.5 goodyear front runners that a friend of mine had to make a nitrous pass. I can say without a doubt the drag radials were WAAAY more stable above 175mph than the front runners. I made a pass with them thurs when the x winds were pretty bad and pulled the chute at 182 i was moving around so much then friday morn made a run with very little wind and still felt the car hunting pretty good at 185-195 on the long course. Head gasket was totally done by then so no more speed than that to compare.
I hope that Mike was able to get with Steve and Lee to pass along some of the info that we found and hopefully do some more testing with the DR tires. Maybe a 'controlled' spin to see how the sidewalls fare.
Again, a HUGE thanks to Mike for coming to our pits, the start line and return road several times to check on our safety.
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What vehicle were you guys running?
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HI all
My name is Fred Heckroth and I work for MARC (Michelin Americas Research Company)
I am a mechanical engineer and design tires for Michelin. While I have only been there for 3 years, I can tell you there is an immense amount of effort, math, testing, and technology that goes into designing a tire. In short the process is mind boggling. I could not begin to address it here.
While I will admit I don't know much about the Goodyear (or any other company's) "drag radial"... there are some things that about tire design that are universal.
I am sure ---> as your distance traveled on drag radials increases, you margin of safety decreases...significantly.
My opinion---> while you might get away with it 10 , 100, 1000 times, eventually you will find the limit.
Question---> why go there?
Fred
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What vehicle were you guys running?
White 96 Firebird # 9614 in B/FALT
I had hoped to see you guys run but my friend said there was an engine problem Sat or Sun?
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HI all
My name is Fred Heckroth and I work for MARC (Michelin Americas Research Company)
I am a mechanical engineer and design tires for Michelin. While I have only been there for 3 years, I can tell you there is an immense amount of effort, math, testing, and technology that goes into designing a tire. In short the process is mind boggling. I could not begin to address it here.
While I will admit I don't know much about the Goodyear (or any other company's) "drag radial"... there are some things that about tire design that are universal.
Fred
Fred Thanks for coming aboard. Apparently the big issue is sidewall strength during a spin. Do you have any data that would help regarding sidewall ply thickness/strength for various tires? What does Michelin have to offer in a tire that would be compatable with land speed racing and how many side plies? I am absolutely not opposed to using other tires but I'd like to know the reasons why. Looking at some posts it seems like the only tires that should be run at Bville are MT or Goodyear LSR specific tires and I get that but there are a good 80 percent or more people who dont run those there and are going 200-250 pretty regularly. Again they are using REGULAR front runners and not LSR specific tires (I looked at a lot of tires in line). Hopefully you can let me know why those are better than DR's in the 200-250mph range.
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HI all
My name is Fred Heckroth and I work for MARC (Michelin Americas Research Company)
I am a mechanical engineer and design tires for Michelin. While I have only been there for 3 years, I can tell you there is an immense amount of effort, math, testing, and technology that goes into designing a tire. In short the process is mind boggling. I could not begin to address it here.
While I will admit I don't know much about the Goodyear (or any other company's) "drag radial"... there are some things that about tire design that are universal.
Fred
Fred Thanks for coming aboard. Apparently the big issue is sidewall strength during a spin. Do you have any data that would help regarding sidewall ply thickness/strength for various tires? What does Michelin have to offer in a tire that would be compatable with land speed racing and how many side plies? I am absolutely not opposed to using other tires but I'd like to know the reasons why. Looking at some posts it seems like the only tires that should be run at Bville are MT or Goodyear LSR specific tires and I get that but there are a good 80 percent or more people who dont run those there and are going 200-250 pretty regularly. Again they are using REGULAR front runners and not LSR specific tires (I looked at a lot of tires in line). Hopefully you can let me know why those are better than DR's in the 200-250mph range.
Did you look at the "D" compound number on the Frontrunners? I would bet that most of the Frountrunners you looked at were LSR tires.
http://www.racegoodyear.com/tires/pdf/drag_front_runner.pdf
Check out this pdf on Frontrunners. LSR tires at bottom
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I have to agree with Mr. Revolutionary that many run non-LSR tires although the number might not be as high as 80%. Here is a picture of the front tires of a car that is in impound every year. Every record is over 200 MPH. I wanted to know what tires they were running. So I took a pic to take home and look up the number. That Front Runner tire costs $149 and has no load rating! I know the car and it is most likely generating about 500-600 lbs of down force on the front end at record speeds. A similar LSR tire costs $499 and is rated at 1,700 lbs load. The engine builder told me the car runs titanium con rods. I don't get it. . . expensive rods but cheap rubber? But in all fairness . . . failures of the drag front runners are relative rare. And maybe less that LSR tires that get destroyed by FOD. So far SCTA doesn't consider the drag tire an issue.
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Reading the complete thread there seem to be some misunderstanding. There are two kinds of Good Year front runners. One is a drag tire and the other LSR. They are both made in the same mold! They look exactly alike and you cannot tell them apart unless you look at the 4 digit hardness number. They are made for two different environments and obviously their cost is different.
I took the picture to show you as much of the "Front Runner" logo as I could but still get in the 4 digit number. This is an LSR tire and costs $499. The same drag tire costs $139. SCTA allows the use of the drag tire but I wouldn't run it. YMMV
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Sorry about the serial postings. :wink:
I remember talking to a streamliner driver at SEMA quite a few years ago. He was extremely proud of how he got a hold of some surplus (but new) Lear Jet tires. He wanted them because they were small diameter. His thinking was what could be better than something made for a jet aircraft. I tried to explain how he was using something exactly opposite of its design function! Aircraft land at high speed but the tires are at their lightest loading. (carrier landings are excused). As the plane slows the load increases as the wing looses lift. LSR is completely opposite. The lightest load is at low speed (the start, etc) and load increases (aero down-force) as the speed increases. He promptly shredded both front tires the next year. After that SCTA changed the rule book requiring a 45 day approval for non-rated tires.
Think about it. Drag racing is exactly opposite the LSR environment. The front tires carry almost no load due to weight transfer. Then high load for about 5 seconds (chute deployment)! Load decreases as speed decreases. LSR is completely opposite. Load increases (aero down-force) as speed increases and lasts for 2-3 minutes! LSR cars are heavier than a drag car.
Other than centrifugal force, Heat is what kills tires. Load x Speed x time is what creates heat. LSR is the worst environment. Do you really want to use a drag design completely opposite its intended use?
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I have run regular front runners over 270 mph and others have run them up to 300. The trick to making a regular drag race front runner work at high speed is to cut or grind most of the rubber off the tread and especially on the edges. The difference in the land speed front runner is it has 6 plys and several more wires in the bead. Then they removed over 50% of the tread especially from the shoulders. The tires weigh virtually the same. The 24" front runner is what funny cars run and is very stiff in the casing as they create a lot of down force at high speed. I actually have a picture of a well known streamliner that has the #D2981 front runners on it. When I asked about it he said the important thing was removing the rubber and increasing the load capacity with a lot air pressure. This was before the Mickeys became available. I have since change to the LSR tires and would recommend them to anyone over 250.
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I was definitely looking at the compound. All LSR tires start their compound wit '22__'. Anything else is a drag tire.
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I hear a lot of speculating.
First of all there are many factors that determine tire strength, speed and traction. It takes a new engineer about a year and a half to come up to speed with all that is involved in tire design so it is near impossible for me to impart it all here.
The rubber compound number (at least for Michelin, BFG, Uniroyal and a few others I work with) pertains to the tread surface only, and has nothing to do with the rest of the tire. I am confidant that this is universal throughout the industry.The tread rubber is no deeper than the lowest groove,(just the outer layer for a slick). It does not give any indication of speed capability. period
When you talk about a tire's speed rating it is largely a function of its internal construction. There are about 5 or 10 different rubber components and numerous non rubber components in the average street tire. For speed... the construction elements that mater the most are the construction elements just under the tread. But wait there's more! speed alone is not what you are looking at when you read the speed/load rating. All parts of a tire are interconnected and work together, so you cant stop there. when a tire is rated it is rated at a certain load at a certain speed. As the tire rolls it flexes. Flexing causes heat. The side wall must carry that heat and be able to dissipate it faster than it is being generated.
So:
A drag radial's "design concern" is with traction, off the line, and relatively nothing else! Heat build up is a real concern.
An aircraft tire is concerned with high speed with enormous load. The Lear jet tires were designed to carry an aircraft that weighs something like 12500 lbs at speeds close to LSR. Your car probably weighs far less and so heat build up should not be a concern. But these tires have extremely heavy construction so top speed becomes a concern.
Increasing the air pressure will reduce flexing and therefore reduce heat build up, but does nothing for stresses generated by high speed (probably aggravates it).
Shaving off tread will reduce the weight of the tread sculpture therefore lessening the internal stresses generated by speed, but does nothing to address heat build up(probably aggravates it).
Sidewall plys, bead rings, and special belt packages effect tire performance in numerous ways, to speculate if a certain tire is applicable for a purpose outside of it's design intent based on "Ply rating" or "belt package" or "bead ring" is just that...speculation. without data and testing there is no way to know.
There are no street tire applications that I could recommend. That being said, a "Z" rated tire, especially a Michelin or BFG (and i say this not because I work for Michelin but because there is a marked difference between Micelin/BFG high performance tire construction and Goodyear or any of the others), would I think be a better choice than drag radial or aircraft tires. Keep in mind that if you exceed the rated speed of any tire you are in uncharted waters. But the internal construction of these tires is probably closest to what you are looking for (you already know this I'm sure).
I am not familiar with Frontrunners construction so i will have to research. Bear with me... I'm old but I'm slow. It might take a while but I'll get back to you.
Well I've probably said too much. If I were going to put my butt in a car that goes 200mph + on a regular basis I would probably wait till i could afford LSR or similar type tires. It's your life.
Fred
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The streamliner I mentioned went over 350 mph with the the non land speed tires. There have been times in the not to distant past when land speed tire availability dried up. The practice of removing all but a little bit of the tread eliminated the problem of high centrifugal force throwing chunks of rubber off the tire resulting in failure.
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(Snip . . .)
An aircraft tire is concerned with high speed with enormous load. The Lear jet tires were designed to carry an aircraft that weighs something like 12500 lbs at speeds close to LSR. Your car probably weighs far less and so heat build up should not be a concern. But these tires have extremely heavy construction so top speed becomes a concern.
The highest speed the tire will ever see is at lift-off or landing. (about 110-125mph for the Lear). That is 2x-3x slower than LSR use. But in general, at the tire's highest rated speed the load is ZERO! In both cases the wing is carrying all of the load! On the takeoff roll the wing produces lift and removes weight from the tire. On landing, assuming 500ft/min decent and reasonable flair, the wing is carrying most of the load when the wheels hit and load increases only as speed decreases. We have all felt some bad landings that seemed like 3 Gs. The reality is that the oleo struts absorb most of that and typical landings are less than 1G. Compare that to LSR when the load only increases as the speed increases.
There are many Lear variants with various takeoff weights. Landing speeds can be 110-125 MPH. I'm generalizing here only to keep the point simple. There are also 4 main tires on a Lear. So divide AC weight by 4. Now compare that environment to LSR. Just when the Lear tire typically sees no load and max speed, the LSR car is increasing load and increasing speed! Just the opposite of design intent. Not a good plan.
If I were going to put my butt in a car that goes 200mph + on a regular basis I would probably wait till i could afford LSR or similar type tires. It's your life.
Fred
I couldn’t agree with you more. :-)
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Hi Saltfever,
I don’t want to debate the inner workings of a Lear but I think you are missing the point.
The Lear 25 weights 12000 lbs, the 60 weighs something like 17000. Divide that by 4 and its 3 to 4 thousand pounds per tire. The momentum of landing is much greater than you think. Remember F= ma. If you want to calculate the load figure the time it takes for the strut to absorb the impact (1 sec). The shock strut travel (12 inches) and the rate of decent on touch down (20fpm). Remember the tire must withstand the maximum touch down rate the aircraft is designed for ( and if its designed for me it is going to have to be stout). When 4 thousand pounds is decelerated from 20 fpm to 0 any way you look at it that tire is going to take a beating. Throw in a tail wind and a short runway and you are getting to the design intent.
On a good day a Lear45 touches down at 130kts = 149mph but that is not the max it is designed for. There is always the chance of a zero flap landing which can up the speed generously.
The load transfer on takeoff is as you say but not as gradual as you think. A jet maintains some positive ground contact in the event of engine failure to maintain directional control (until V1 speed).
We don’t design, and the government won’t certify, parts that are designed to never exceed normal usage. We design for worst case scenario. Aircraft tires must withstand extreme loading/beating.
Fred
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http://www.landracing.com/forum/index.php/topic,8282.0.html
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Hi Fred and thanks for the continuing discussion. Yep, I agree . . . the purpose of my response was not to debate the characteristics of the Lear. As I said there are a bazillion flavors of the AC type and I was generalizing. Also, to keep things simple I left out information. But to support your point even further the landing gear system on all aircraft must meet G load factors. AFAIK, on general aviation, all parts of the system must accept 3Gs without failure. That means the tires must take not only the weight you mention, but 3x that weight! I am aware of the tremendous loads they must survive. However, that is not my point. The invisible load you are missing is centrifugal force. As you know, it increases as the square of the speed! In LSR, OEM VR or ZR tires are approved up to 200mph. So I thought we were discussing the use of a Lear tire over 200 mph and speeds far beyond that. You have already mentioned the incredible mass and multiple plies these tires have. So if your Lear is rated for 150mph and you run it at 300 mph the force is 4x its design and all that mass is working against you! The tires I saw shredded failed in the low 300 mph range.
We are both in agreement . . . neither one of us would run them . :cheers:
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Saltfever,
amen brother !
Fred
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I very rarely take part in these discussions but for those of you interested this was my official reply ;
Hi Daryl,
We are very wary of tires we are not familiar with. And these tires are also a lot wider than the majority of cars use.
For tires that are not originally designed for sustained high speed use, we have a supervised limited speed program we will put you through.
This will consist of supervised runs at , 175mph for the first (depending upon license), 185-190 for the second, 200 for the third, then 210, and so on.
The tires will be checked after each run for heat, damage, wear, or any other unusual effects they might suffer.
Handling problems or irregularities are also a concern with wide tires, this is another reason you will be supervised.
Be advised that the race surface on the salt is very different to Maxton.
Please contact Joe Timney for advice on the surface differences.
Please make yourself known to myself or Lee Kennedy upon your arrival in the tech area.
Regards,
Steve Davies.
Chief Car Inspector SCTA/BNI.
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Thats my 2 cents worth.
If anyone needs to reach me, my email is in the rule book.
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Kiwi
on those aircraft tires they were talkin about in this thread.... havent we been limiting them to 250mph....
kent
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Not all wide tires have handling issues, just cars that have the wrong set up. :mrgreen:
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Hi Kent,
All aircraft tires (or any tires seeking approval) go through the entire tech committee process, they have the final say.
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pretty sure they have a 250 cap.... Right Stainless?
kent
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Kiwi, just wanted to say thanks for all the help you guys gave and to let you know that I could not have been happier with how Mike went the extra mile (so to speak) to make sure he was on the return road at the end of every pass checking out the tire wear and temps. I had backup tires available (which I did end up using) but hopefully I can bring these back next year and we can do some more testing with them. In the mean time, I'm going to try to get in touch with whoever I can at MT to see if there is any further testing they can provide that will help out.
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Kiwi, just wanted to say thanks for all the help you guys gave and to let you know that I could not have been happier with how Mike went the extra mile (so to speak) to make sure he was on the return road at the end of every pass checking out the tire wear and temps. I had backup tires available (which I did end up using) but hopefully I can bring these back next year and we can do some more testing with them. In the mean time, I'm going to try to get in touch with whoever I can at MT to see if there is any further testing they can provide that will help out.
How did the two tires compare and what were the temps?
JL222
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Both tires and rims absolutely cool to the touch and the drag radials handled much better.
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Both tires and rims absolutely cool to the touch and the drag radials handled much better.
white car, my mistake. :-D
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Both tires and rims absolutely cool to the touch and the drag radials handled much better.
What air pressure did you run in the drag tire?
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Salt...I asked that on the first page and never saw a reply..............
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Salt...I asked that on the first page and never saw a reply..............
That is an important question! That is why I asked it again. :wink:
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OK, not quite on the topic, but relevant. At Speedweed we had a fairly low speed spin. I told the driver "go fast at the other end". Anyway at reinspection the Goodyear "Drag" Frontrunners were deemed unacceptable to continue racing. The tires are roughly 10 years old and had been exhibiting a circular seperation in the sidewall about 1&3/4" above the rim. After the spin you could feel the sepertion and peal the sidewall back about 1/4' toward the rim.
Anyway, I bought a set of LSR Goodyears from Gary Hart. With the cost I want to get the maximum life out of them. Looking at Jim Dincau's link I had some questions:
1. Can you get nitrogen at a welding supply store?
2. I have seen posts about storing LSR tires without any "Air" in them. Does this go for nitrogen filled tires?
3. I have also seen posts about storing the tires in black plastic bags in cool places?
Can you comment on these and any other methods for extending the life of LSR tires?
Tom
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1.) yes
2.) N2 is good. It displaces O2 as well as Ozone (O3) which is bad and hurts rubber. Just release the pressure.
3.) Yes. Black plastic bags help with No.2 above and also shields UV which is very destructive.
4.) Climate controlled environment (no temp changes) is even better. Put them in your wine seller. :wink:
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Yeah, if I could afford a wine celler, I probably wouldn't be worried about the price of tires.
My boxes of wine seem to last fine for 2 weeks at ambient temps.
Thanks for the info on Nitrogen.
Tom
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When we were road racing we found that nitrogen had different amounts of humidity depending on the grade and the conditions the cylinder was filled in giving us uneven tire pressures. Our solution was to run the nitrogen though an inline dryer. For the LSR car I found a dryer off a compressor from a clean room. I still need to build a small chassis with some casters to hold it, but if you want I can take a picture of it and post it tomorrow. Tony
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Salt...I asked that on the first page and never saw a reply..............
That is an important question! That is why I asked it again. :wink:
Sorry, I was running 44psi
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836 --- Just what is the best temperature to store a box of wine? Funny stuff ... Joe
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Carnauba wax them before storage?