I would like to buy tires to go on the track with my Challenger.
It's a street car but want to go to on a real track this summer in UK ( SantaPod ).

416 ci with weiand Xcelerator, 727 with Transgo TF2, rear end 3.73 + Gear vendors.
I shift at 5800-6200.
Converter is 2500
Edelbrocks heads with 0.525 camshaft and 237 duration. prosystem carburetor 850 cfm DP

Today my best time with street tires, Avon CR6ZZ, track was not good.
diameter of tire, 27", 275x55x15.

13.02 @ 110 Mph, 60'@2.25

What diameter and width do you think?
And Slick or quick time pro?

thank you

Stock suspension challenger is likely limited to a 275 tire. If you search here, you can see some have stuffed 295 tires but you do not have a lot of gear and those tires will be a lot taller.

You need a stickier tire. I have no idea what options are available in France, nor what is legal. There are several popular drag radials, with the MTs and Hoosiers most commonly used, in 275/60/15. The MT drag radials are advertised for use on a daily driver but they are not really well suited for wet weather.

If you can get your 60' time down, the car should be able to hit at least mid-12s. You don't have a lot of converter, so slicks may not buy much over a drag radial. You will need to work on the simple suspension items such as shocks to optimize the combo.

With only 3.73 gears, I would stay with a shorter tire. If you want it to look good, the 275 is gonna fill the wheelwell, but you'll likely be faster with a 255 or even the 26x10 ProBracket Radial.

I agree that the small block / heavy car / 3.73 gear combo is the main issue here. If you really want to get well down into the twelves (and it looks like you have enough power to do that with a 110 trap speed), strongly consider a gear ratio change. 4.10 with a 26" tire or 4.30 with a 28" tire would be good guesstimates. The best way to work out the combination is determine your peak HP RPM (chassis dyno) and approximate the converter slip on the big end (trap speed versus trap RPM + some math) and then pick a gear / tire diameter configuration that puts you through the traps 200-300 RPM over your peak HP. Your Gear Vendors will help keep the car cruisable with the steeper rear gears.

If a gear change is not in the cards, get the shortest (26" or less), widest (9.5 - 10" tread), softest/stickiest tire you can (275/50-15 DOT radial or 26 x 10 slicks), take the front sway bar off (or at least disconnect it), and put some old soft (or 90/10 drag) shocks on the front and go have fun, you should still crack into the twelves. and can put the bar/shocks/tires back into street trim for cruising.

It would really help if we knew what gear and what rpm you were crossing the line at. This info would determine tire height.

I run a 295/55 and that puts it through the traps
at 7000 rpm with a 4.10 gear.. with a GV you have
to be damn near at idle at 75 mph.. I am 2900 rpm
with my 518 in OD(no lock up)at 75 mph.. if I went
much lower it would hurt MPG with the cam I run

When I cross the line, I'm in the 3rd gear and at 5100-5200 rpm. Today I run with my street tires, 27" diameter.

I don't want to change my rear end because this summer I'm goint to make more or less 4000 miles to go to the different tracks and holidays.

These new tires are only for the track.

Well then, you sure don't want a taller tire (60 series). If you are keeping the same gears, you will need to lower your tire diameter. Tire sizes along the lines of what Stealthwedge67 recommended. If the widest you could fit is a 275 tire width, see if there is a 50 or 45 series profile, which would give you a lower sidewall/overall diameter. This would give you both, lower 60 ft. and higher trap rpm.

Yes, on the highway, I'm at 3000 rpm for 83 Mph. I don't want to change because many miles this summer and in France, gas is very expensive around $6 for 1 gallon.

My actual tires, Avon, are only for the street.
If I bought 26' diameter, I will be at 5500 rpm for 114 Mph.

Maybe I have to change my converter, 3000 instead of 2500.
If I change it, it will be always ok, 3000 stall on the highway?

Just like any other aspect of racing, make one change at a time. I would try a set of race only tires first. Changing torque converters can only make fuel consumption and highway rpm worse. 114 mph trap speed should put you well into the 12 second bracket.

Ok, thank you.
You're right, step by step, for the moment tires.

I went on the summit site and saw some tires :

Quick time pro 26x9.5
http://www.summitracing.com/int/parts/hoo-17415/overview/

Hoosier drag slick 26x10
http://www.summitracing.com/int/parts/hoo-18131/overview/

or MT pro bracket 26x8.5
http://www.summitracing.com/int/parts/mtt-3352r/overview/

What would be better for tracks?

Based on the differences in track surfaces and track preperation from here in the U.S. to those tracks in Europe, based on actual expereinces when I was assign to duty in Hanua, Germany. I would buy a bias ply tire, not a radail No matter the tire size I built and raced a semi fast pump gas street and strip Duster(ran high nines in the 1/4 on pump gas motor only with the exhaust and air cleaner on ) and used both M/T ET Street(bias plys) and M/T ET Street Radials of the same exact size as well as using a set of M/T 10.5x31x15W drag slicks, the slicks where the best at the track as far as ET and MPH, the Radials where faster on a good track than the bias ply tires where but on a not prepared well track and on the street the bias plys where way better Buy the biggest size that will fit on the car and use the widest rim you can get on the car, even if the rim is wider than the tire thread width is IHTHs
IHTH

Hi, for Santa Pod Proper 26" Bias Ply Drag Slick will be best, or a radial slick perhaps as they now prepare the track some for RWYB's. Your right on with 5500rpm/114mph, unfortunately I doubt with that 2500 converter you will run the 11.6's that mph equates to?......always a trade off for street/strip....I used to run a '71 Cuda 340 on the street with a 4200 verter and 4.30 gears w/26.5" road tyres, 50mph was 4000rpm, didn't run that too often down the Highway!!!

26 inch sounds like a good start. As wide as possible to fit without hitting anywhere.

Thank very much guys.
I'm going to order them.

Bon chance.

My son runs 3.91's in his Dart with a 400 eng and he uses Hoosier QTP tires that are 26 x 9.5 and they work good for him. I would think a 26" tire at the track should work good for you. Ron

With stock spring location and stock ride height I used to get a 29 x 10 slick on an 8 inch rim in there, can't remember the back spacing but it was pretty close to the lip of the rear arch and the leaf spring, IIRC it touched the spring when turning the corners. You should be ok with the 26 x 8.5 but you may foul the tyre somewhere with a 26 x 10 slick depending upon the wheel offset. A 10 inch slick can have a 12 inch shoulder width.
HTH's