drag slick vs. drag radial

I'm currently running hoosier 31.5 12.5 W 15, stiff side wall, have had good luck with them for bracket racing, the problem I'm running into is keeping the front end down on the launch, depending on weather changes I could have a pill set to just barley bring the front end up then the later in the day the air gets a lot better and the big wheelies start and I need to pill down on the break, what I was thinking if I switched to the m/t drag radial in similar size, I could keep the trans pill low, not pull a big wheelie and still cut good 60', ive heard radials are a lot less forgiving than slicks, the car is at 2650 pounds with a small block and 904, so witch one would be the best option???

The problem of the front end in the air has nothing to do with the tire, or even the power level. Simply put the setup isn't right.

You think it wants to wheelstand now on a slick, likely be way worse on a drag radial

The problem is the car is short, Plymouth arrow, its a 50/50 tube chassis car, but I figured with the radial I could keep the trans break pill low and not hit it so hard with the power, ive herd you get better 60' with the radials, so I wouldn't loose the 60' times and keep the front end down, would using a bigger tire with more roll out help out?

Where is the instant center point, and what shocks are on the car?

I'm not sure where the center point of the car is, I had it scaled last year because it was going right on me, now that I think back on it it was a 51/49 set up with 51 on the front, its a 4 link car with afco single adjustables in the rear, up front is a spindle strut set up from the early 90's, no adjustment other than the coils, there are no markings on them for brand, the car leaves dead strait now sence the scaling, I mean I can chip the break down a lot and never worry about the wheelies but starts to leave like a turd, ive also been told to go higher on the pill so it doesn't flash the converter so hard, but the higher I go the higher and longer the front end goes up and out. the wheel base is only 96 or 98 long, at the end of the season last race the air was really good but had a 35 mph head wind, had a 3200 pill in the car and it was just coming up and touching the bars and back down nice, then as the wind picked up and air got better it was carrying the front end out and really high then coming down and bouncing though 2nd, then I chipped it down to 3100 and it didn't even pull the tires off the ground at all, and 60' fell off

Radials hook or they don't. And they DEAD hook, no tire slippage. So if it picks up the front when the slicks dead hook, it will do it EVERY time on radials.

The keep the car from picking the nose up on slicks is an easy concept. You need MORE wheelspeed to rotate the tires a little to keep them from dead hooking. So you need more power, less tire pressure, tighter settings on shocks, more front weight, different instant center......something

If you have non adjustable front struts from the 90's, I would say you have spend some money on good shocks before anything. Second would be replacing the rear shocks with some double ajustables.

How much front end travel does it have? Tieing the nose down might help if it has a bunch of travel. Finding the instant center would be good too and adjust from there

Strap the front end down and or buy some better shocks.



As Monte said, a radial will only be worse.

How fast is your car? At some power level the 51/49 will be too light up front no matter what you do.

How do you keep the front end down on a radial?

WEIGHT and suspension settings. We have to run our Drag radial car at around 56% on the nose to keep it down

Is it true you need a higher gear with a radial than a slick? Guys keep telling me I need a 3.91 or something that area. I keep thinking that is only good for boosted cars. I can't imagine that formula works with NA.

I'm told you want around 6.60 when you take; 1st gear x rear gear ratio = 6.60

SLR(starting line ratio) is all about managing the power you have. Ours is 5.32

FWIW:

At your power level the dead hook or spin on a radial things is true. I'm an 11 second car and I can feel my Pro Bracket Radial "buck" or "slip" and recover. I felt it "spin" and I lost .01 in the sixty two weeks ago

Also, even at my power level........I raised the front end (wanted to change the stance of the car) and started having spin problems with the PRB.....while at the track on that same day.......I dropped the front end height back to the former height which was like a 1/2" drop at the track and the spin stopped

The best the car has done is 9.79 at 137, usually runs low 9.80s through the summer, 1.32-1.35 60' times,

Front suspension travel length, and how fast it comes up can be the deciding factor of it spinning, and hooking.


I love the pbr's


We've been 1.14 on the 28s with a 3000lb mustang.

Just put a set on my car a few weeks back. Way better then the 275 pros on the street so far.

The front doesn't have a lot of travel, the car comes up extremely quick when it does, I think I'm going to move the bottom 4 link bar up one hole on the housing to move the center forward, the car originally had a big block in it before we bought it as a roller, I think moving the bottom bar up will be the cheapest and easiest thing to try first, still kinda interested in the drag radials though, we will see what it does with the slicks first

Where is the 4 link now and where will it be when you move it? You can't just think that LOOKS right or like it might help. You need to KNOW where it is and where it will be.

Also, a tube chassis, short wheelbase car with a loose strut is not a good plan

I seen in your earlier post one of the things to do is to move weight forward, wouldn't moving the bottom bar of the 4 link up a hole on the housing put the weight forward? I get what your saying, check everything out before I start making changes, but I was thinking I would start there

I used this to find instant center on my car. With a string line and some tape for making marks. On my ladder set up putting the front pivot right on the instant center line where it crosses made the biggest improvement. Now its just shock settings.



Theres some more info if you search 4 link tuning on google or whatever you want to use.




Hope these help.

On a ladder bar car, the instant center is the front pivot. You can raise or lower it, but the length never changes because the length is whatever the ladder bar is and that doesn't change. Same with a leaf spring. A 4-link has a "virtual" instant center because the bars are spread and the IC is an imaginary point. Moving the instant center out, up, down or back on a 4-link deal changes how the car reacts, but doesn't physically move any weight. If the car is 50% on the nose, you can move the bars wherever you want and it's still 50% on the nose. So moving the lower bar as you described will likely lengthen and lower the IC, but that in no way means it won't wheelstand. If it's light on the nose and dead hooks, it's still going to wheelstand. That picture above is misleading. It says "similar" IC locations. Really the only thing similar is the length, the heights are different, so that means the IC is different. Suspension is about leverage and how it applies that force to the chassis. The bottom bar is always pushing and the top bar is pulling, so you have to visualize how that will effect the chassis. Long ICs put the pickup point further forward and this is where it tries to push the chassis up