Winger4800

I am plotting to get one of the following:

et streets or drag radials with 15" wheels (weld prostars)

First off i was told that 15" wheels will not fit my 89 formula because it has the ausi 9bolt with rear disc. BUT IF THEY CAN WORK HERE'S MY DELIMA:

If i choose the et's i want to keep the same tire height so the gear ratio will be the same. (or smaller will be fine. I just dont want a taller tire that will hurt the gearing and "slow" me down)So what would be the best size to run?

If I choose drag radials, which size would be better? 275/50/15 or 275/60/15. Either one will be going a 15X8 rim.

My goal is for my car to hook! My car isnt THAT fast where i must have et's. It's an 89 formula 350 with bigger TPI, 2500 stall, headers, exhaust..etc. right now on street tires it's a 13.50 car. I eventually want to supercharge it but that wont be for atleast a year. I would like et's but as long as i can get a drag radial to hook i will go with them......


Also, what size backspacing will i need for the rims to fit my car? What is my bolt pattern? I should know this but i'm too lazy....

IHI

iTrader: (1)

Simply put, ET streets-they work with less than perfect suspension set-up. Your slow enough you can probably get by with radials, but they may not hook deadly consistent every pass as the bais ply's will.

the 275/60 (28" tall) will work best because it's a taller tire and your putting more contact area to the ground becasue of it.

The 275/50 (26" tall) you may take a chance at over powering them since it is shorter (less rubber on the ground) and your overall gearing will be numerically higher than if you used a 28" tire.

Depends on what your ultimeate application will be. If your going to try some bracket racing, do not even consider a radial tire design. If all your worried about is fast ET then start looking at the drag radials since consistent 60' times wont be of concern for you.

Winger4800

Thanks for the help but i still have some unanswered questions....

IHI

iTrader: (1)

15" rim
8" wide 4.5" BS
10"wide 5.5" BS
4.75" bolt pattern

Have no idea bout the brake issue with the 9 bolt fitting inside a 15" rim

itsjustabird

iTrader: (1)

i cant say for sure how the new michey thompson radials hook on our cars stock suspension but hey rick head 7.60s smooky hall 2 weeks ago here in florida set the record for first nitrous drag radial car to run 7s with a 7.87 @181 so they will definately hook my friend has a "stock" suspension mustang with gears and dropped the clutch @6000 on motor and didnt spin a bit in fact it tried to bog the motor first with only those mods he cut a 1.80 60 ft I am extremely impressed with these tires im buying some within the next month just slightly larger 325/50/15 just my 2 cents also have you ever driven in the rain with slicks i promise a radial is a much better all around tire ive cut 1.7 60s with a wore out and hardened set of nittos that were 3yrs old

IHI

iTrader: (1)

board screw up....

IHI

iTrader: (1)

another bad post

IHI

iTrader: (1)

Not flaming or spamming you but you have alot to learn. Those 10.5" cars are not a stock car that they just throw a huge turbo or shot of nitrous on, they are a finely tuned race car that have the chasis and suspension tuned with a fine tooth comb to be able to hook up with these drag radials. You cannot and will not see a stock suspended car doing anything impressive with any amount of hp/tq with stock suspension and just throwing on a set of drag radials, even if they hook so-so once in a while I promise you they will NEVER repeat a 60' number back to back ever.

Your buddy with the mustang and gears dumping the clutch at 6K and ONLY gettinga 1.80 60' needs alot more than just his "gears" and ridiculous clutch dumps if that's all he can bring to the table. If a 1.80 is his 60' then yes I firmly believe these radials may hold, but once you start getting 1.70 and lower...you need to get your suspension working perfectly for a chance, and again I will promise you it will not repeat 60's times back to back, they will be all over-ESPECIALLY in the heat of the summer with a less than perfect track surface.

Lastly, if you get caught in the rain with DOT slicks, full slicks, and yes even these drag radials, you are in for a white knuckled ride. These drag radials do not have the rain channeling design like regualr street tires do, the tread depth is so shallow even when new they are no better than a DOT cheater slick, and give your new radial slicks 1 day at the track and see how much tread you have left. After a few days of what I consider "normal" time at the strip you will have a tire with no signs of tread left.

Another racer summed it up better than anything I've ever heard:
"If you want to race run the radials; if you want to win run the bais ply"

Most guys-and I'm not saying winger4800 is one of them-just do not have the time, and /or budget to do the testing to get their suspension/chasis dialed in so they can make good use of these radial slicks

Case in point, another member of this board came and raced with me at our track where traction is awesome on race day and most all the cars set-up that bracket race seriouosly do not move .003 all day long in their 60'. Anyways, he comes up here with his new M/T drag radials (he normally runs ET Streets-but also heard he'd be faster with the radials so he tried them) he jumped from 1.7? to 1.8? all day long NEVER repeating a 60' ever and his overall ET/mph package showed. He has pictures with the ET streets mounted going 1.6? 60's pulling the front tires off the ground, his pictures with the radials he ALMOST gets the front suspension to top out.

Winger4800

lets say i was to get skinnies for the front? what size is best? would these work?

click here

IHI

iTrader: (1)

For strip only the 3.5" rims work perfectly. Be sure you mount about a 27-28" tall tire on the front of the car, this will help you ot go red. Tall tires slow down your R/T short tires speed them up, it's easier to go with a tall tire and add air psi to quicken your R/T than have a short tire with no place to go, you can let air out of the tire, but there's a point at where it's unsafe also.

Most guys run the 165/75 tire and this is only 25" tall, but if your car's a behemoth and your new to racing, you may be alright with them inistially, but think about taller when you upgrade.

If this is going to ba a street/stripe car like I have, opt for the 5" wide front rims. They will take the abuse of the pot holes better than the narrow rims and allow a slightly wider front tire for better on road manuvering/handling.

Winger4800

i'm goin with the 275/50/15. I'm still considering what todo for the fronts....I think i will run a 15X5 front. i dont know what size tire i should use........205/50/15 or 205/60/15?

IHI

iTrader: (1)

Since your going with such a short rear tire (26") and given the fact a short front tire will kill you on reaction time if your any good (shorter front tire=faster reaction time-taller front tire=slower R/T)

So to keep the balanced look heigth wise the 205/60-15 would be the best bet. The 50 series which is considerably shorter will be harsh on the street thanks to no sidewall and also tend to help you go red once you figure out the tree.

Depending on how serious you ever plan to hit the track I'd personally recommend at least 275/60-15 as they are pretty close to 28" tall as this will greatly help aid in traction should the summer sun start makng the track fade away in the traction department and then 205/75-15 which are 27" tall so you can fine tune your R/T with air pressure. more air R/T will be faster less air it will be slower. Before I got my transbrake our track used to be incadesant bulbs and I would have to run 50psi up front to cut decsent lights, at the NHRA track with LED's I had to drop them to 25psi so I did'nt go red.

Low profile tires just are the thing to have when you want to bracket race, try any competative racing on a drag strip, not to mention with tires as short as your thinking about I dont know how well you you'll like the look you end up with. Depending on stance of your car, it most likely will look like a 4x4 since you'll have so much space between the tire and top of wheel well.

Just my opinions though

BadBowtie88

WERD. After doing a couple of things to my '89 before I rebuilt the motor, I threw on a set of Nitto DR's and headed to the track. Guess what? Spun as if they were regular radials. Went online and paid a pricely sum of $60 for some aftermarket LCA's with poly bushings. Installed them and went back to the track. My 60' times not only jumped from squirrely 2.2x's or so, to CONSISTENT 2.0x all day long. With ONLY aftermarket LCA's. Can only imagine what it's gonna be like when I actually complete everything this time with the new motor....

IHI

iTrader: (1)

One thing you guys need to remember and I'm not cutting you down, those 60's being claimed on here are not impressive and are not going to push the limits of a radial tire much less a drag radial. I drag raced my first season with junk off the shelf 245/60-15 MasterCrafte $35tires, stock suspension getting as low as 1.84. Even that is not impressive, but geing stuck with a daily driver tire it is'nt too shabby. Once you get the gearing and hp so your consistenly in the at least the lower 1.70-1.75 range, THEN without suspension tuning you may start to see these tires being taxed and inconsistent.

Not to mention short tire life. Before with my small motor I could go a whole summer racing every weekend, driving all over town on 1 set of Hoosier Quik Time Pro's, I will literally put money down with anybody that a drag radial will not hold last half that long.

I'm not runnign down the tires and they will work great for under powered undergeared daily drivers, but once you step upto a more powerful drivetrain, you will need to address the suspension area as well.

BadBowtie88

I agree 100% with you. My 60' times are nothing to be proud of, I was just pointing out what only ONE piece of suspension will do for you combined with a drag radial tire. Keep in mind I was only running 14.3x's to 14.4x's with those 60's times. Was just agreeing with you. I was in NO way taxing those tires, but, it was doing me absolutely no good having a drag radial w/o any suspension to back it up.

Winger4800

What kind of lug nuts will i need for the weld prostars??

I got 15X8 4.5 bs rear
15X5 3.5 bs front

TunedPort 335

Talk to Summit, I have the same exact wheels... you will need a 12x1.5 pitch (I beleive). It is going to be a long shanked lug nut. The guys at Summit looked it up in the book and they fit perfect for me.

For the front 15x5s i am running 205/70/15 Toyo Spectrum radials. They are a stock height tire and they should ride very good

Winger4800

what size tires do you have in the rear?

Winger4800

205/70/15? why so high? Oem for firebirds and camaros are 235/60.15?? so whynot go with 60 height to retain stock height?

KagA152

iTrader: (5)

they are the same height or very close to it. the second number isnt a measurement of the side wall. it is the aspect ratio, the percentage that the sidewall is high as to the tire is wide (thats badly worded)

mw66nova

iTrader: (13)

IHI, i respect you ALOT, but your not entirely accurate about your 60' consitancy issue with radials

my father has all off the shelf suspension parts:
hotchkis lca's and panhard rod
spohn torque arm for powerglide

all of which is readily available to anyone and is a direct bolt in. he is running a stock ride height, and while he has a set of lcarb's, he has not installed them yet.

he ran a set of 275/60/15's drag radials for the longest time and ran consistant 1.7x's 60' times. the non impressive 60's are due to the power glides lazy 1.82:1 first gear, but, non the less, the car was consistant, and ran 11.7x's all day long.

Winger4800

what did he run up front???

Winger4800

what did he run up front???

mw66nova

iTrader: (13)

195/50/15's or something REALLY small like that.

mw66nova

iTrader: (13)

here is a pic of the car from the side. don't mind the bad paint job, it was fixed last summer, but this is the only decent side shot i could find of the car on the web.

IHI

iTrader: (1)

But you have to figure in that dad has the power of prayer on his side also

TunedPort 335

Stock my tire height was 26" (215/65/15). Right now my tire height is 26.3" with the 205/70/15. Not a noticeable difference really. Like Kaga152 said , that second number is the "aspect ratio" or the percentage of the width that makes up the sidewall.

Right now for rear tires i have 245/60/15's but will be upgrading to 275/50/15's once those get burnt off.

12secformula

Hey I am not trying to hi-jack this thread, but where can I get some steel skinnies like what is on mw66nova's dads car? I have seen them a few times, but never found out where you can buy them. It would be cool if someone could help. Thanks,

Kyle

mw66nova

iTrader: (13)

summit or jegs sells them, but you have to call them and ask. the manufacturer is Bart Racing Wheels.

12secformula

thanks man, i'll have to check that out.

BlownBird

The 15" wheels will definately work with the rear disc brakes on the aussie9.
If you are interested, I have a set of draglites
15x10 5.5bs
15x5 for the fronts
all lug nuts included (even have 1/2" if you want to upgrade rear studs)
No rubs or scrapes will let go for $400 plus shipping for all.
DonB

Winger4800

check your pm

BlownBird

Nothing in my p.m. box...

anesthes

iTrader: (12)

Second that. I ran 15" firebird rims for years with a 9bolt. I ran slicks on a set of monte carlo rims. Only thing Ihad to do was file about .0000001" off one caliper cuz the inside of the rim wasnt perfect.

-- Joe

Winger4800

ok so i made up my mind. 275/60/15 for the rear. 28" tall. So what should I go with in front?? I'm getting 15X8 for the rear and 15X5 up front.....so would I need a 28" for up front right? whats the best size then?

mw66nova

iTrader: (13)

a 215/65/15 or a 205/70/15 would be what i would run up front. actually a 215/65/15 is what i am running up front. they are 26" and 26.3" respectively. my sig has a pic of my 275/60/15-215/65/15 tire combo

IHI

iTrader: (1)

I run 205/75-15 up front, 27" that way it flows a little better with the 28" rear tire i run, and helps with roll out as well.

83 Crossfire TA

iTrader: (2)

That sounds familiar... I'm running 215 65 15's on the front and 275 60 15 BFG DRs on the rear of my formula on a set of stock firebird rims. Actually it’s suprising how light that combination is… even with heavy GT+4’s on the front the wheel/tire combination only weighs 34# each, which is quite acceptable for something that is big enough that it handles like a normal street car.

Winger4800

Final question i swear!!!

What size lugnuts do I need for weld prostar 15X8 rear and 15X5
in front???

keep in mind I have the 9 bolt rear.......

83 Crossfire TA

iTrader: (2)

Um, what studs do you have installed in it? My 9" has 12x1.5mm GM style lug nuts in it. I ran across one last week that had some 14x1.5mm (current lugs used on most of the newer 2500 and bigger trucks) installed in it that the owner swore were "either 9/16 or 5/8"

Prostars need shouldered style lugnuts...

mw66nova

iTrader: (13)

if it has stock studs, it needs some sst style lugs in the 7/16" diameter.

Winger4800

I have stock studs...... whats sst????

mw66nova

iTrader: (13)

oh, sorry, they are the style of lug nuts you want. they are called SST. they are a shouldered lug nut. jegs has kits for 16 lugnuts, 4 wheel locks, washers, and valve stems for like $25.

errr, you need p/n........hold on........359-EK151C if you get them from jegs. that's actually a REALLY good deal too.

83 Crossfire TA

iTrader: (2)

Stock studs for what?

Most smaller ford applications (cars) use ˝-20 stuff, the larger stuff like the trucks can use lots of different stuff.

Stock f-body is 12x1.5mm, like I already said.

7/16” is what GM used in the 70’s and earlier, not sure where you’re getting that size nova…

mw66nova

iTrader: (13)

really?

oh boy, glad i didn't order my lug nuts yet! i guess that makes sense though, everything else on the cars are frickin' Metric...

Winger4800

So now i'm confussed?? Now I SHOULDN"T order that set from jegs????

mw66nova

iTrader: (13)

take one of your current lug nuts to the parts store. they normally have one of those little displays that have all the different size/style of studs sticking out of it. thread on the lugnut to whichever one it fits and the get that size/style.

for the prostars, you need a shoulder type lugnut, it's called an SST. get those in the size/style that you need. *should* be a 12mmx1.5