Landracing Forum
East Coast Timing Association => ECTA General Chat => Topic started by: manifest on January 20, 2012, 06:52:52 AM
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Looking at rear tires for our Modified Sports class car and just wondering what some of you high hp guys are running for rear tires? We already have a 28" GY Frontrunner on the rear for Bonneville use (may end up getting the actual LSR tire) but for Wilmington we will need a drag radial i'm sure. Looking at the GY and M/T 275/60R15 but just wanted to get opinions before I order anything for our 8" wheels.
Zach
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Looking at rear tires for our Modified Sports class car and just wondering what some of you high hp guys are running for rear tires? We already have a 28" GY Frontrunner on the rear for Bonneville use (may end up getting the actual LSR tire) but for Wilmington we will need a drag radial i'm sure. Looking at the GY and M/T 275/60R15 but just wanted to get opinions before I order anything for our 8" wheels.
Zach
We have been really happy with the M/T radials.
Geo Turner
Geezer Racing
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the mickey thompson drag radials are amazing.. i think they might even hook in the rain.... lol but seriously once we put them on the #1946 roadster there was no more tire spin with over 900 hp
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Have either of you ever had any problems with them slipping on the rim or doing anything funny on the top end due to the way they grow at speed? I remember seeing some of the NHRA Hemi SuperStock cars running radials years ago and they all got a weird woblle at the top end. Does anyone run wheel screws or beadlocks?
Zach
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We haven't had any problems except on the wheel dino. No slippage in the rim. No locks,been 210mph
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Me too, just don't run no pressure, thats when you'll have problems. Think street use type pressures. your results may vary though.
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We ran Goodyear Taledega race tires at Maxton in the fall and will be running them again
this year in Ohio. I bought them at Penske Racing in Reading Pa. BGMS class
Dave
#3611
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Just beware with the drag radials if you are going really fast. Some of the real high power cars running 220mph plus in the mile have had tire failures due to their growth and the time they spend at speeds like that in the mile.
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Just beware with the drag radials if you are going really fast. Some of the real high power cars running 220mph plus in the mile have had tire failures due to their growth and the time they spend at speeds like that in the mile.
Do you know which drag radials and what starting tire pressures ?
Charles
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we run 28 psi-35.Goodyears and M&H. went to good years to get taller tire.
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I don't know the pressures but I believe they were Mickey's. The Hinson Corvette crashed because they grew enough to touch the car and come apart. The LMR Camaro I believe had a tire debead. Both were well north of 220mph or so. I also heard that M/T told them not to run them at those speeds for that amount of distance. 1/4 mile is ok but not the mile.
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If the drag radial tire slips on the rim, drag racers have been using Permatex High-tack to glue the tire to the rim. Screws are not recommended by MT, IIRC. I slip them about 1/2" per pass drag racing with no high tack.
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It's not so much that they slip on the rim but the centrifugal forces cause them to grow alot and could potentially make the bead separate from the wheel.
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I talked to a Goodyear Rep. at PRI last month and he explained that Drag radials were just what I should run. Hard launches are not a common place thing in LSR stuff. I have about 8 complete sets of Good year and M/T tires that we used in open road racing. I have not felt comfortable using these in a mile event. In my opinion they are good tires but really need a lot of heat in them. They are really good in corners
but I think in a stright line traction is a problem. It would also require more camber that I would feel right running. I think I will stick with the drag radials. I question them growing . Radials by their nature are much more stable and with steel belts not as prone to grow as a bias ply. Has any one noticed "C" shaped tires at the traps? Getting this old farts Camaro to not spin in first is a on going problem and resulted in short shifting and even leaving in 2nt all last year. Even when Pete reported no wheel spin, the pictures taken from the truck showed different. We were running about 27 PSI cold. We had moved the instant center alot for the last meet. That seem to help. Comments?
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Our instant center is way out front of the truck and it nearly dead hooks leaving the pushtruck at Maxton but we have a real tall 1st gear and weigh near 4000lbs in mile trim. We have been running the M/Ts with no issues but from my understanding they are not recommended for much time over 200mph or so.
I also just came across this on the M/T site..
TIRE USE ON A DYNO
Mickey Thompson tires which have been subject to use on a Dyno must no longer be used for subsequent, normal service. Use of Mickey Thompson tires on a Dyno will invalidate the tire warranty.
At no time should the following Mickey Thompson tires be used on a Dyno:
ET Drag
ET Motorcycle
Pro Drag Radials
ET Street
ET Street Radial
ET Street Radial II
This is Mickey Thompson DRAG / STREET Technical Bulletin #18.
For more information regarding Mickey Thompson Performance Products ph: 330.928.9092
We try not to use any sticky tire on our dyno because they get chewed up and suck up alot of HP but until now I did not know that it voids the warranty.
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Our experiance on the D/BSTR roadster at Maxton by viewing photos and video taken crossing the finish line show the M/T drag radials growing a lot in diameter at 200 to 206 MPH. The tires do not display the C shape like the top fuel boys experiance they are still very round just a lot taller. The increased diameter adds to the overall final gear ratio which of course adds a bit more MPH.
On my Lakester the photos and video taken at the finish line at Maxton show the M/T drag radials I run have grown in diameter even at the lower speeds I have run which to date is just under 175 MPH. The added diameter change has helped me gain a bit more MPH over what the Mark Williams wonder wheel figures say I should get with the RPM, gear ratio and tire diameter I run. So far Im very happy with the results using the drag radials.
Ronnieroadster
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I guess my question is how can you tell the grow. To say they grew an inch or two from a picture taken from 100ft away is not really proof. Do you have a gauge to measure? Based on my pictures I haven't seen the growth. Rumors of the tire separation problems were caused from too little pressure. Not from the speed itself. Host went faster then anyone with mickeys and had no problems. How do cars 20 mph slower have issues. I didn't know race tires had a warranty.... I didn't know race anything had a warranty an. Guess I wouldn't expect it. I have blistered. Bran new mckey t on the dyno tho
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Hmmm. Interesting thread.
I am new to land speed racing but I have been a Michelin research engineer for 5 years now.
I understand the need for traction but why drag radials? I know Michelin (as well as other manufacturers) makes several sports car tires with very soft compounds that are intended for speeds in excess of 200mph. They are the “(Z)” rated tires (not to be confused with “Z” ). I know drag radials (or any drag tire) will beat these tires off the line but the (Z) should run circles around drag tires at speed. They are designed for extended high speed driving applications on “super cars” and they are sticky. They won’t grow like drag tires so why wouldn’t they make a good LSR tire? Just curious.
Fred
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If you are doing 170 to 190 My guess is that a pass takes 20 seconds or so. Even at 201 to 206 around 20 or so seconds. Not very long and the tires won't be in that range until the very end. I would guess tire separation could be caused from bruising . If you tow in the trailer with your race tires there is one spot that will be abused the entire time. I have also had a 12 ply tire that was brand new come apart . I had hit a chuck hole at speed on the way to Bonneville. Not unlike what we did all the time at Maxton. Thats why its important to run your tires all the time. A bruise will start a seperation that will lead to total loss of the tire. Keep looking at them. I also can not verify that drag radials grow. As a rule, the tires we run are too narrow to balloon. My program gives me a speed for RPM. It is always high. I either have drive line slipage or tires are slipping. Twice I have flashed the traps at a RPM that I was sure would produce a 200 MPH hat ,only to find out that is was not that fast. So were they getting smaller. I think not.
As a side note I have run almost the same tires above 165 for 118 miles .
They got greasy at the finish but were still okay.
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My two cents on "Z" rated tires. They Will do okay. All the road racing rubber I have run over the years required heat to work. They also are designed to turn. That should require very different side walls. Also every "Z" rated tire I ever ran I had shaved down to 3/32 before they worked. I do believe the rolling resistance is higher. As simple as it sounds on the LSR stuff "for me" it has boiled down to how easily does it roll. How much traction does it give me in third. Most of the cars are running 700 HP and up. Those that are hitting 200 I would guess are 800 . That will produce slippage at speeds. I don't much care if the car pushes or is tight. We have alot of caster and a little toe in. As a rule high speed cars that turn, run toe out as it causes the car to turn in faster. There are a jillion suspension twicks that cars that turn use. Cars that go straight have the ability to go straight and continue going straight. I for one am looking for every little thing I can find. I would have Ceramic Bearings on the front end and in the rear if I could afford them. After I win the lottery maybe. But in my mind "small as it is" I want a tire front and back designed to go straight. I only need to turn at the turn off.
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that should read (Y) speed rating which are marked "Z" but are different. sorry for any confusion
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I can't imagine that a radial (M/T, MH, Hoosier, GY, BFG, etc.) would beginning to fail in just one mile. The radial drag cars are doing burnouts then lauching and having sub 1.20sec. 60fts. with them and the life of the tire is only the sidewall lasting. As for the Y/ Z rated tire I have only ever seen ones made for production style wheel, i.e. 17" and bigger and most do not have much hieght. BUt is may be something to look into. Right now i am still leaning towards the 28" GY radial for our Datsun.
Zach
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Our experiance on the D/BSTR roadster at Maxton by viewing photos and video taken crossing the finish line show the M/T drag radials growing a lot in diameter at 200 to 206 MPH. The tires do not display the C shape like the top fuel boys experiance they are still very round just a lot taller. The increased diameter adds to the overall final gear ratio which of course adds a bit more MPH.
On my Lakester the photos and video taken at the finish line at Maxton show the M/T drag radials I run have grown in diameter even at the lower speeds I have run which to date is just under 175 MPH. The added diameter change has helped me gain a bit more MPH over what the Mark Williams wonder wheel figures say I should get with the RPM, gear ratio and tire diameter I run. So far Im very happy with the results using the drag radials.
Ronnieroadster
Thats how we found out our tires were growing, when the 5 mile exit speed was higher than the rpms that were turned and what the computer and dream wheel said they ought to be. Rpms were about 300 less, adding 11/2'' tire growth to tire diameter made the time slip and rpm to come out right for our 275 mph time slip.
JL222
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Greenjumk
Your asking for a measurement? Dude the tires grow at speed THE PHOTOS at the mile PROVE THAT bottom line if you use them make sure you have addtional clearance in the fender area so you do not rub them causing a failure at speed. The drag radial tires are awesome one less detail to think about for a LSR vehicle.
Ronnieroadster
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I've used them for years with no clearance problem. I just don't see how you can tell from the picture that the tires grow. From my calculations I'm not seeing any diameter change at 200 and I run a narrow wheel and a wide tire providing even more opportuniy for growth. That's why I asked whether you had a way of measuring or if it was your best estimation based on what it looked like
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Hi David
The added clearance to the ground on my Lakester under speed is at least an addtional 1 to 1-1/2 inches under the rear of the belly. IM very concerend with keeping the car as low as possible {who isn't}the move to Ohio will allow me to lower the car since we no longer should have any concern with rocks and any rough surface to tow the car on. After viewing the 8x10 action pictures of my car carefully I have determined I can go a bit lower with the suspension in the rear to compensate for some of the height gained at the finish line. Not sure if one inch lower is possible but IM sure going to try and lower it that much and see if can even get her out of the shop and onto the trailer.
The tire growth on the roadster was great enough to cause the tires to rub on the fenders a bit of tire smoke was visable on the top end the tire growth was definitely greater on the roadster at a much higher speed.
Ron
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Got it. That makes more sense. I'm probably not seeing the tire growth because I'm getting 250 of downforce at 200 plus I have an extra 175lb of balast I'm thinking that's keeping the tire looking more "normal". You don't get the priveledge of downforce in a tanker
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We use the drag radials at Maxton.. and have not had a problem even though we weigh over 4,000lbs and are running close to 200mph. I am convinced they do grow, based on our RPM/Speed calcs, but would be interested to see how much the growth difference is at varying tire pressures for the same speed. Let's put my GoPro on the tanker and see what they do up close! I would do it on my truck.. but we are about out of tire room already and we would have to provide light in the wheelwell......
Kix
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OK,, seems like maybe I should buy the M/T ET Drag Radials,,, 235/60/15 (26 X 9.50 X 15)
The M/T's on the Vicky are 27.1 tall and 10.5 wide,,, they are to wide and to tall,,,
My experiance with the M/T's (on my 1933 Vicky sedan)has been much better for launch up to 1/2 mile,, but seemed greasy at the finish..
(it was a brisk cross wind that day,, and I may not had enough air in them,, only 26psi)
I will order the M/T's for the Studebaker,,, any starting air pressure suggestions ??
Charles
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Hi Kix
Great idea about the Go-Pro it remined me I did use the Go-Pro on one of my last runs pointed rearward I wanted to see the chute deploy. Looking at the video again it looks like to me using my old eyes I can see some increase in tire height. The video would have been better with no cloud cover and not running over the patch to view the tire better but its interesting anyway I think.
The car was moving around a bit a combination of needing a little more suspension work and a driver{thats me} who's not so nervous kind of like driving a go cart on steroids.
Ron
http://www.youtube.com/watch?v=yTd5W1psJa8&feature=related
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A sunny day would certainly have helped the cause! Sure looks to me like the tread gets wider right after you pull the shoot. Nothing dramatic... but we are talking about 1/2" diameter growth spread over the whole circumference of the tire.... so it wouldn't be anything dramatic to see. We'll mess around with the camera more at Wilmington and see if I can get one right up close in the fender well... maybe I can drill a hole in the wheel tub and look straight across the top of the tire. Hopefully it will be smooth enough there to see what is going on.
Kix
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OK,, seems like maybe I should buy the M/T ET Drag Radials,,, 235/60/15 (26 X 9.50 X 15)
The M/T's on the Vicky are 27.1 tall and 10.5 wide,,, they are to wide and to tall,,,
My experiance with the M/T's (on my 1933 Vicky sedan)has been much better for launch up to 1/2 mile,, but seemed greasy at the finish..
(it was a brisk cross wind that day,, and I may not had enough air in them,, only 26psi)
I will order the M/T's for the Studebaker,,, any starting air pressure suggestions ??
Charles
Start with 30psi then go up or down.dont try 40psi :-o
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Before you settle on a tire talk to MT, Goodyear, Hoosier etc, and they will all tell you that their drag radials (not drag slicks) are not suitable for LSR and only should be used for short bursts of speed as in 1/4 mile racing. Nitto was the only tire manufacturer that endorsed LSR for their drag radials.
Even with the qualification that it is only 1 mile, they all stated that they should not be used. I don't go fast enough to worry about it....just saying....talk to the guys who make them about how their products should be used.
Peter
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Without sounding crazy {I am sure I will} I have found most manufactures as soon as you say LSR will tell you the product is not suitable. I was trying to buy a wheel from a major manf. They supply NASCAR type wheels . As soon as I told him it was for LSR racing he said they would "not sell those to me". He explained That the wheels were not suitable for those type of speeds. When I explained that NASCAR cars go 200 at Daytona. He said of course. I still bought those wheels from a dealer instead of the factory. Seems its okay to bump wheels and corner at crazy speeds with high "G" loadings. But to go straight is a whole different matter. In this Law Suit happy world and with the mystery with LSR racing it is not a suprise that tire manf. would say things like that. How many years was it that no one made a LSR tire for Bonneville. Just a few months ago I saw some 20 year old tires for sale. And the price was as high as new ones. Watch your tires , maintain air pressure and don't cut corners . That will work for me. Read the disclaimer on that racing tire sticker next time you buy one. Like some one said earlier there is zero warranty on racing stuff.
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My understanding is that the tire makers are fine with racing on their tires, to certain speeds. When you tell them LSR, they assume 250mph or more for an extended period of time. Those drag radials are not meant for those speeds for that amount of time and they know that and that is why they tell you not to run them AT THOSE SPEEDS. Now 200-220mph I believe is just fine but there have been failures running over those speeds in the mile.
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Kumho makes a 225/50/15 that is Z rated. They are only 24" tall but they would work. There are also quite a few companies that make Z rated 16" tires if you havent already ordered wheels.
Here is a link to the Kumhos:
http://www.summitracing.com/parts/KUM-1794213/
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Well if your going to run street tires and spring for 16in wheels why not go to 17? Michelin makes a tire called Pilot Super Sport start in that size. It is a soft compound (durometer number of 69/70) tire designed for high speed. How high? I am not allowed to say but I am sure you will never exceed the tested limits in a mile... unless you are shot from a cannon. The PSS is made with the C3M process so is nearly perfectly round and uniform . No other tire is. because of this they require almost no balancing weight. They have no "joint" to separate (the usual cause of your tire coming apart at high speed). They have kevlar windings to control growth (they do not grow). They are as close to a road race tire as you can get for the street. I'm simply not going to say one way or the other if their durability exceeded the capabilities of our test equipment. That might get me in trouble. But i can tell you that our test equipment is second to none. Of course that is solely my opinion and does not by any means reflect the position/opinion of Michelin. I work for Michelin but their position on LSR is "stay as far away as possible". The way they see it LSR has nothing to offer except liability. The way i see it i want the safest tire i can get that will still get the job done.
Fred
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Fheckro is right on the money! For a more reasonably priced (read lower) similar tire (though not quite as sophisticated), check out the BFG's....owned by Michelin.
Peter
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R-1 is a good tire and liked by alot of people for track days. It needs to be heat cycled first. Somthing we can't do in LSR racing. A few companys offer heat cycling
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The problem is no companies offer a narrow enough tire that is tall enough. a 24" tire on a 900hp car is like trying to get traction with tires made of butter on frying pan. we need 26-28" tall and 275 wide, thats not a 22" rim.
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That is true
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Here are some Drag Radial tread hardness numbers from our tests.
MT 49
Hoosier 48
M&H 47
GoodYear 53
Nitto 57
BFG 51
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The problem is no companies offer a narrow enough tire that is tall enough. a 24" tire on a 900hp car is like trying to get traction with tires made of butter on frying pan. we need 26-28" tall and 275 wide, thats not a 22" rim.
Check out the Michelin site and download the tire size chart for the PSS... I bet you'll be surprised how many diameters you can get. Joe and I have both been looking for someone to make 18" steel wheels... I found someone who has 18" spinnings and he said he can make laser cut plate wheels for about $185 each... We're considering going this way because the PSS has a 27" tire that fits in the truck's wheel wells...
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The problem is no companies offer a narrow enough tire that is tall enough. a 24" tire on a 900hp car is like trying to get traction with tires made of butter on frying pan. we need 26-28" tall and 275 wide, thats not a 22" rim.
Check out the Michelin site and download the tire size chart for the PSS... I bet you'll be surprised how many diameters you can get. Joe and I have both been looking for someone to make 18" steel wheels... I found someone who has 18" spinnings and he said he can make laser cut plate wheels for about $185 each... We're considering going this way because the PSS has a 27" tire that fits in the truck's wheel wells...
What size was 27" tall ? I need a 27" tall and narrow say 9" wide to 9.5" wide section width (tread width around 8.5 to 9.0")
Send me info on the 18" wheels as well..(my guy makes 15" and 16" wheels not 18")
Thanks
Charles
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Firestone makes a Firehawk PV-41 16" V rated 26.6" Dia. These were made for Police Cars. Used to make a 15" also.
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I attached the Michelin Pilot Super Sport table of the tires I found applicable to LSR, but will send it to your email too Charles.
The wheel manufacturer is Marsh Racing Wheels... nice guys.
http://www.rockcrawler-mrt.com/offroad%20wheels%2018%20inch.html
Kix
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Kix,
Thanks
Charles
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Guy's,
Marsh Racing Wheels are what we have on the 974 Studebaker since we built it. Good people to do business with.
Hooley
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Hooley,
What rear tires did you use when you ran at Texas ?
Charles
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Charles,
We put B.F.Goodrich drag radials on. They worked good but we were able to over power them. I think for running on concrete I need a 4 link rear suspension instead of ladder bars. I will readjust the ladder bars for Ohio and add some weight. Maybe that will do it.
I am looking it a NASCAR tire too.
All in the name of FUN.
Hooley
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Hooley,
If you have room to fit those wider Nascar rear slicks,, try the
Tire GoodYear brings to Talledega for the Left Front
I hear they work good.
I don't have room to use that wide a tire.
Charles
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Has anyone tried BFG R1s ?
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Have run R-1 on a track day, a couple of times. They are a great cornering tire and turn in very nice. We were running 1/8 tow out that helped. Side walls I think are Stiff. Don't think its a good mile LSR type tire. I think the BFG drag radial would be better
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I already have rear M/T Drag Radials so I have ordered Set of BFG Drag Radial II's (and are having them Heat Cycled)
this way I will KNOW which works best and which fits best.
The Heat Cycle process cost $15 per tire, but since it is under a controlled process and we don't allow burn outs, it seems the best choice to properly season a race tire,,,
Charles
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Thats the best $30.00 you will spend.
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Thats the best $30.00 you will spend.
Bob, I sure thought so myself...This way I know they have been properly heat cycled.
I ran my M/T's on the rear of the Vicky..(I did two little burnouts in my driveway before I loaded on the trialer,,, that was not enough,, Learned my lesson)
CV
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It took about 8 passes at Maxton to get the back tires right. They were green and would not scuff . On the last pass in OCT. we started getting good scuff patterns. I think my Home owners association would frown on me doing a burn out in front of the house. They all ready do.
We were running Goodyear Eagle DOT drag radials. THey should be just about right in April.
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I attached the Michelin Pilot Super Sport table of the tires I found applicable to LSR, but will send it to your email too Charles.
The wheel manufacturer is Marsh Racing Wheels... nice guys.
http://www.rockcrawler-mrt.com/offroad%20wheels%2018%20inch.html
Kix
Further on down the road... we have been looking for 18" - 20" wheels to run the Michelins on... and found these unbelievable beauties.
http://www.landracing.com/forum/index.php/topic,11174.0.html
There is also a new Goodyear Land Speed tire that is 10" wide and costs about the same or less than a drag radial.... two more options!
Kix
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Further on down the road... we have been looking for 18" - 20" wheels to run the Michelins on... and found these unbelievable beauties.
http://www.landracing.com/forum/index.php/topic,11174.0.html
There is also a new Goodyear Land Speed tire that is 10" wide and costs about the same or less than a drag radial.... two more options!
Kix
Size Tire Code Compound MSRP Rim Width Overall Diam Section Width Tread Width Weight Min Inflation (psi) Max Load (lbs) Max Speed (MPH)
28.0x10.0-15 2270 Hard $229 9.0 28.0 13.2 10.3 22.0 70.0 1700 300
Interesting!
Mike