LSR Tire Recommendations Needed

[bvillercr]

What kind of suspension are you using; stiff, soft, none?

[Dr Goggles]

I am not much of a pro, having only run one year, but  narrow tires and a whole lot of lead is the way to go.  I ran my 1990 ZR1 with 4.5 X 28 X 15 in the rear and about 2000# of lead with 640 Hp and it ran straight and true to 219 mph.  tried removing 100# from the rear in an attempt to go faster earlier. And things got way loose once I was over  215,  on the salt weight is definately your friend.  Also one of the  things I learned was that its still a drag race, and you need to hook up early if you want to get to 230 plus you better be going 215 by the  2.25 mark, as a whole lot of track goes under the car every second once your at speed.

my comment after my first run was man, 5 miles is short:)
 
Good Luck

Dave

ABSOLUTELY...............it's funny but it's not til you're up against it that you really see it as a problem....from the outside it seems obvious but when you are going fast, the track goes away pretty quick...if you want to go fast you have to accelerate, the faster you go...the less time you have to do it, and ,er, then you have even less time, to go faster.....we were putting on 12 mph a mile, over the last three, no wheelspin  , we could use a little more power

but I definitely agree...you need to be getting going EARLY in order to be going later

[jdincau]

Here is a data point;
152 inch wheelbase,solid rear, sprung front, modified roadster,weighs approx 3,500 lbs. 372 cu in blown on alcohol, has run as fast as 270 MPH.
We tried an experiment, back to back runs with 7.00-18 Firestone LSR tires and 8.00-15 Goodyear stock car specials. The Firestones were traditional narrow rock hard LSR tires, the Goodyears were standard bias ply stock car tires with about a 10 inch wide contact patch. Speeds were the same but the driver said the narrow tires were much easier to drive and the wide tires were "squirrely".
Jim in Palmdale

[jdincau]

It definitely is a drag race if we aren't going 245 in the quarter it's over. You just have to be able to accelerate with a little finesse.
Jim

[bvillercr]

Here is a data point;
152 inch wheelbase,solid rear, sprung front, modified roadster,weighs approx 3,500 lbs. 372 cu in blown on alcohol, has run as fast as 270 MPH.
We tried an experiment, back to back runs with 7.00-18 Firestone LSR tires and 8.00-15 Goodyear stock car specials. The Firestones were traditional narrow rock hard LSR tires, the Goodyears were standard bias ply stock car tires with about a 10 inch wide contact patch. Speeds were the same but the driver said the narrow tires were much easier to drive and the wide tires were "squirrely".
Jim in Palmdale

I agree with you on open wheeled vehicles.  Wide tires have too much aerodynamic down fall.  For doorslammers it is completely different, so are set ups.  

[jl222]

I am not much of a pro, having only run one year, but  narrow tires and a whole lot of lead is the way to go.  I ran my 1990 ZR1 with 4.5 X 28 X 15 in the rear and about 2000# of lead with 640 Hp and it ran straight and true to 219 mph.  tried removing 100# from the rear in an attempt to go faster earlier. And things got way loose once I was over  215,  on the salt weight is definately your friend.  Also one of the  things I learned was that its still a drag race, and you need to hook up early if you want to get to 230 plus you better be going 215 by the  2.25 mark, as a whole lot of track goes under the car every second once your at speed.

my comment after my first run was man, 5 miles is short:)
 
Good Luck

Dave

  How was it with wide tires and a lot of lead or less lead?
 

                      JL222

[Bruno]

as to suspension, we were moderately stiff, with 52 % weight to the Rear.   I thought about using a four link set up to get a better weight transfer, but that just works for the hole shot, and not what you want at speed.  I had two problems last year, I could not get on the wood, untill I was long in second gear due to wheel spin, and  once I hit 215 I was at the aerodynamic limit of the body and was getting several inch's of lift in the front, even with a lot of weight on the front.  The Factory lift numbers for my vette are 440# of lift at 200 mph, so you can see how much this changes on a production car with just a  small increase in speed.
What I can say is the car ran straight and true, like it was on rails untill I took some weight out of the car then the tires broke loose at top speed, I had to pull the chute to prevent a spin.
I have not tried the wide tires, but  in 1990 when the zr1 came out it was run at bonneville, bone stock.  According to the team, I was told it was horribly unstable at 180.  Once again production body.

I believe, you will find once you vist Meca ( the flats) and see how, loose the first 1/8" is and how hard the surface is underneath, you will come to the concusion with the majority, that what you want is a small foot print with a lot of weight.    But Hey go for it and good luck.

[bvillercr]

as to suspension, we were moderately stiff, with 52 % weight to the Rear.   I thought about using a four link set up to get a better weight transfer, but that just works for the hole shot, and not what you want at speed.  I had two problems last year, I could not get on the wood, untill I was long in second gear due to wheel spin, and  once I hit 215 I was at the aerodynamic limit of the body and was getting several inch's of lift in the front, even with a lot of weight on the front.  The Factory lift numbers for my vette are 440# of lift at 200 mph, so you can see how much this changes on a production car with just a  small increase in speed.
What I can say is the car ran straight and true, like it was on rails untill I took some weight out of the car then the tires broke loose at top speed, I had to pull the chute to prevent a spin.
I have not tried the wide tires, but  in 1990 when the zr1 came out it was run at bonneville, bone stock.  According to the team, I was told it was horribly unstable at 180.  Once again production body.

I believe, you will find once you vist Meca ( the flats) and see how, loose the first 1/8" is and how hard the surface is underneath, you will come to the concusion with the majority, that what you want is a small foot print with a lot of weight.    But Hey go for it and good luck.

Bruno....I just don't know where to start with this rediculous statement that you just made.  I know your a rookie at bonneville so I will try to be easy on your ego.  Our car has been running at bonneville for over 20 years.  We built the car for the purpose of this sport and modeled it very closely to Gale Banks firebird.  Our car puts out four times the power that yours does.  We run a four link, and Goodyear 2222's they are fatties.  Last year we ran 268 in the 1/4 and 285 in the mile, so your trying to tell me that a small foot print is better.  I'm not saying that skinnies are bad, and many have gone fast with them but only two maybe three doorslammers have ever gone faster than ours in that first mile.  We also run a soft suspension set up and we launch pretty good even at the 1/8 mile.   Maybe you should read our build diary (Getting ready for Bonneville) and check out our set up.  

[Bruno]

Thanks for not rubbing that in, Hey,  I am alway willing to learn , I checked out your build diary, hard to argue with your success. Way cool car.
 All the records in my class are set with skinnys, so maybe  I should not be following the rest of the sheep.  With a non Altered Body fighting lift at speed its hard to put the weight where I need it for launch, and still keep the front down.  I will looking to a softer spring rate, that could be my ticket to impound.

[SPARKY]

LOTS of Rake 

[jl222]

It definitely is a drag race if we aren't going 245 in the quarter it's over. You just have to be able to accelerate with a little finesse.
Jim

  Yea Jim ...I consider it a drag race unless your middle mile speed is as fast as your last mile exit speed

                               JL222
 
  If your last mile speed is as fast as your exit speed on second thought.