What do I need to know to choose slicks for my race car?

[Clelan]

This past spring, I purchased a 73 Plymouth Duster, that was a former Pro class bracket car. It has a 436 small block stroker, 727 with about a 5k converter, 4.56 gears. It has stock front suspension w. 90-10 shocks, rear ladder bar suspension w. Single adjustable coil overs. It weighs right about 3000 lbs. I only made 4 passes in it this year because of time comments etc. It hooked good with just a slight slip on launch.
Currently it has 29x10.5-15 Hoosiers with tubes on 15x8 Weld Wheels. The tires are screwed to the rims on both sides.
I plan to switch to 10" wide wheels and 28x10.5-15 tires because I hate the look of the cut out fender openings in the back. I'd prefer no tubes, and no screws if at all possible. I am open to bias, radials, whatever. The car will be bracket raced a few times a year (as much as my schedule allows).
I am new to all this, so I'd love to benefit from the experience of racers here.

Cley

 

[Demonx2]

Track only tires or dual purpose?

 

[Clelan]

Track only. This car is not street legal.

Cley

 

[TT5.9mag]

There are guys running 7.50s on 10.5 drag radial. I say pick a tire in a size and style you like and make the car work with it.

 

[ValiantRacing]

Radials

 

[Clelan]

There are guys running 7.50s on 10.5 drag radial. I say pick a tire in a size and style you like and make the car work with it.

Eventually that is what ill do, I am just hoping for a bit of " This worked for me, and here's why I liked it." or "I tried this and I hated it and here's why." I am currently running a slower 12 second Duster on drag radials, but that's all the experience I have.

Cley

 

[GTX JOHN]

We run 9.0 x 30 Goodyear Radials running
mid to low 10s and low to mid 1.3 @ 60ft.
3300 lb Demons with Cal Tracs

 

[318willrun]

We run 9.0 x 30 Goodyear Radials running
mid to low 10s and low to mid 1.3 @ 60ft.
3300 lb Demons with Cal Tracs

This ?
Goodyear Racing Tires 5204 Goodyear Eagle Dragway Special Slicks | Summit Racing

 

[GTX JOHN]

This ?
Goodyear Racing Tires 5204 Goodyear Eagle Dragway Special Slicks | Summit Racing

Exactly what we run on our cars.
There are two similar tires = One with
92.5 rollout and one with 94 rollout.
I run the tall on both the wagon and
the Demon Stockers. Jon runs the shorter
ones.

I believe this tire was designed for the factory
shoot out cars. we are even going to try it on
our Superstock cars when we find the right rims
offsets (2 1/2 back spacing).

 

[318willrun]

Exactly what we run on our cars.
There are two similar tires = One with
92.5 rollout and one with 94 rollout.
I run the tall on both the wagon and
the Demon Stockers. Jon runs the shorter
ones.

I believe this tire was designed for the factory
shoot out cars. we are even going to try it on
our Superstock cars when we find the right rims
offsets (2 1/2 back spacing).

Do they take a lot of heat to hook?
How is the life...?? 100 passes?

 

[Locomotion]

Radial slicks can be a bit faster in ET and RT than bias ply slicks but they are more sensitive to track conditions. In other words, they will spin easier & more if the track isn't in good shape.

Going to a shorter tire will increase your top end rpm and, as MOPARMAGA mentioned, could be too much on the starting line and encourage spinning. I doubt you need more gear multiplication with the stroker and taller tires will work better. Radial slicks also don't "grow" at higher rpm like bias ply slicks so you will have a little more top end rpm with them as well. Do some testing & research to see if 4.30 gears might be better in any case.

Good plan to go to with 10". Actually, 11" rims with 10.5" slicks wouldn't be a bad idea either. You should be able to run a bit more air pressure in the slicks while still maintaining a full footprint. It's common for Stock class racers to use 10" rims with the 9" slicks they are limited to. Always check tire section-width for suspension & fender clearance. Wheel width changes will alter the tire section-width so factor that into your wheel offset computations. Bias slicks tend to have a wider section-width than radial slicks. Look them up. Hoosier race tire specs.

I ran 10" rims with 9" Hoosier lightweight radials @ 21 lbs, no tubes & no screws - 1.47 best 60'. The slicks can move a bit, especially when new. (Put a shoe polish spot on the sidewall across from the valve stem.) It was a pain but I swapped tires from side-to-side after every race weekend to help them move back, clean any feathering off and help insure even wear, if there is any bias. I checked manual brake adjustment while I was at it. Always balance the tires. Rebalance if they happen to move a lot.

Consider at least single adjustable front drag shocks. I had good luck with QA1.

Looks like you have a battery in the back with a master cut-off. Good. Adding a ballast box can be helpful for more consistent traction, adding weight if and when needed. Consistency wins bracket races, not faster ETs. Adding 60 lbs to my bracket Challenger many years ago made an obvious difference in consistency & wins. But you have more adjustability options in your car.

Any odds & ends up front that can be removed for better weight distribution?

Carb tuning & converter flash have a big influence on how well a car launches. (60' times)


Bit-by-bit, test & tune whenever possible.

Good luck!

 

[tabletop390]

Swap out to beadlocks or have your current rims converted. You won’t have to worry about spinning the tire on the rim with whatever tire you choose. Beadlocks can also allow you to play a bit with the tire size and sidewall stiffness. My car is very similar to yours and getting my rears converted to a double beadlocks made a huge difference

 

[RockinRobin]

1970 Duster 700hp gen3 hemi 727 torqueflite Dana60 4.56 gears Caltrac bars 90/10 shocks in front 9 way adjustables in rear
I leave off idle and footbrake the car. I used Hoosier tubeless 29.0x12x15 on 12" wheels for years. Car would hook well on decent tracks, but would spin in later rounds at marginal tracks. I switched to a Hoosier 31.0x14x15 on the same 12" wheels and my issues on tracks with bad prep went away. Car slowed about .05 or .06 but runs it's number consistently.
With 4.56 gears and a 5500rpm converter I had to have good conditions to keep from spinning, but the change to the 31.0 tall tire gave me just enough gearing to avoid spinning, plus going from 12" wide to 14" wide couldn't hurt.

 

[GTX JOHN]

Do they take a lot of heat to hook?
How is the life...?? 100 passes?

No really just enough to clean them off.

The tires will last 200 runs if economical
on the burn outs.

We have very little problems with Wheel spin the
last couple of years with the Radials. Goodyear has
really improved the compound the last several year,
unlike prior to that.

However, As hard as our cars leave and as heavy as
they are we usually replace them @ 100 runs or so.
The issue is a hard leaving/heavy car beats up the side
walls and will hurt the consistency occasionally after
that period.

It helps that we have enjoyed enough success, that Goodyear gives
us some help on our tires!

 

[318willrun]

No really just enough to clean them off.

The tires will last 200 rUnlikuns if economical
on the burn outs.

We have very little problems with Wheel spin the
last couple of years with the Radials. Goodyear has
really improved the compound the last several year,
unlike prior to that.

However, As hard as our cars leave and as heavy as
they are we usually replace them @ 100 runs or so.
The issue is a hard leaving/heavy car beats up the side
walls and will hurt the consistency occasionally after
that period.

It helps that we have enjoyed enough success, that Goodyear gives
us some help on our tires!

they'd charge me extra to have them on my car ....
But good info, thanks

 

[9secRR]

Swap out to beadlocks or have your current rims converted. You won’t have to worry about spinning the tire on the rim with whatever tire you choose. Beadlocks can also allow you to play a bit with the tire size and sidewall stiffness. My car is very similar to yours and getting my rears converted to a double beadlocks made a huge difference

beadlocks on a high 10 sec car? why not use rim screws? beadlocks is WAY over kill and expensive. my car 60' is 1.23 with rim screws

Track only. This car is not street legal.

Cley

track only= drag slicks. MT or Hoosier

 

[Demonx2]

If you know the approximate mph it will (or you want it to) run, I would start with choosing the right height tire for the rpm you want to stripe at. THEN you would pick the width or construction.

As for the avatar, I'd like to run radials but my only experience has been my M/T S/S Street ET radials and they either spun badly or hooked and left. No consistency which means no good for brackets. So when I bought new shoes for the car a couple years ago, I bought the same as was on the car when I got it as I knew they had run successfully on the car before I had it (PO ran 10.80's with the car). They're wider than an 11.0x car should need but hooking the same is never an issue at any track I've run at (Michigan, Ohio, and Florida). 28.0/10.5-15W bias ply Mickey's. I can run anywhere from 12.5 - 13.8 psi in them with my 4.10 gear. I shift the car at 6200 and it traps at 6200 at 119-119.6 mph.

FWIW...

 

[max512wedge]

If you know the approximate mph it will (or you want it to) run, I would start with choosing the right height tire for the rpm you want to stripe at. THEN you would pick the width or construction.

As for the avatar, I'd like to run radials but my only experience has been my M/T S/S Street ET radials and they either spun badly or hooked and left. No consistency which means no good for brackets. So when I bought new shoes for the car a couple years ago, I bought the same as was on the car when I got it as I knew they had run successfully on the car before I had it (PO ran 10.80's with the car). They're wider than an 11.0x car should need but hooking the same is never an issue at any track I've run at (Michigan, Ohio, and Florida). 28.0/10.5-15W bias ply Mickey's. I can run anywhere from 12.5 - 13.8 psi in them with my 4.10 gear. I shift the car at 6200 and it traps at 6200 at 119-119.6 mph.

FWIW...
View attachment 1716462952

That’s a beautiful red demon you have there. If I may ask is it mini tubed and what size rims and back spacing your running. I’m going to mini tub mine and was just trying to figure out how wide of rim and tire I can go. Thanks Bill.

 

[BVoelzke]

That’s a beautiful red demon you have there. If I may ask is it mini tubed and what size rims and back spacing your running. I’m going to mini tub mine and was just trying to figure out how wide of rim and tire I can go. Thanks Bill.

I run a P295/65R15 Hoosier drag radial on my Dart a few of my friends run the same tire. I got away from slicks when I moved to a DOT required tire class , at first I ran Hoosier Quick Time Pros at 10 lbs of pressure , I switched to the drag radial a few years ago and I like them I run 18 lbs of pressure and the car is more stable top end. The class rules changed and I can run a slick now but I like the drag radials. My car runs high tens with low 1.40s 60 ft I run on a throttle stop to run 11.50s and my 60 ft is 1.46-1.48. When I did run slicks a radial slick was faster than a bias ply but as others have said IMO also they tend to wear quicker and can be tricky on a marginal track. I just put a new set of drag radials on about a month ago. I run a M/T 275/60 R15 drag radial on my low 15 second 92 D150 p/u they work well also. My Dart is mini tubbed , narrowed 8 3/4 , springs moved into frame rails with Cal Tracs , I run a 10 inch Holeshot wheel with 4 1/2 inch back spacing

 

[max512wedge]

I run a P295/65R15 Hoosier drag radial on my Dart a few of my friends run the same tire. I got away from slicks when I moved to a DOT required tire class , at first I ran Hoosier Quick Time Pros at 10 lbs of pressure , I switched to the drag radial a few years ago and I like them I run 18 lbs of pressure and the car is more stable top end. The class rules changed and I can run a slick now but I like the drag radials. My car runs high tens with low 1.40s 60 ft I run on a throttle stop to run 11.50s and my 60 ft is 1.46-1.48. When I did run slicks a radial slick was faster than a bias ply but as others have said IMO also they tend to wear quicker and can be tricky on a marginal track. I just put a new set of drag radials on about a month ago. I run a M/T 275/60 R15 drag radial on my low 15 second 92 D150 p/u they work well also. My Dart is mini tubbed , narrowed 8 3/4 , springs moved into frame rails with Cal Tracs , I run a 10 inch Holeshot wheel with 4 1/2 inch back spacing

View attachment 1716467544

Thanks for the info. Your car looks bad azz! Did you open up the rear fender’s wider?

 

[Demonx2]

That’s a beautiful red demon you have there. If I may ask is it mini tubed and what size rims and back spacing your running. I’m going to mini tub mine and was just trying to figure out how wide of rim and tire I can go. Thanks Bill.

Thx Bill. The car is not mini-tubbed but the springs are moved on top of the rails. I have 15"x8" wide rims. I'll have to dig through some records and get back to you on the backspacing as I don't recall it in my head.

 

[BVoelzke]

Thanks for the info. Your car looks bad azz! Did you open up the rear fender’s wider?

Yes , the body man that did it cut it to look stock so it can hardly be noticed

 

[Demonx2]

Thx Bill. The car is not mini-tubbed but the springs are moved on top of the rails. I have 15"x8" wide rims. I'll have to dig through some records and get back to you on the backspacing as I don't recall it in my head.

I looked at my records. The rear Weld Prostars are 15x8 with 3-1/2" backspace.