Just about finished my 74 cuda restore. I need to purchase tires. Anything technically that I should be aware of if I choose 18 inch wheels and tires? I rebuilt the front end with all new bushings, shocks all around, and new leaf springs in the back, new torsion bars. New brake system with disk in front. Power steering. I still need to get it aligned and I was going to install tires before I did that.

I think 18" is a nice size. I run 17's... done again I would do 18's.

I was able to borrow a test wheel and tire for fit measurements then ordered wheels with custom backspace (American Racing). If you are trying to fit the biggest rubber, that helps. Most aftermarket wheel manufacturers will make custom backspace to order.

Once you get close on a tire size and type, look at what is available. I used Tire Rack to explore options. More common sizes have several options which helps with cost.

the basic would be if the OD will clearance/ proper fit your wheelwells 3 to 9 o'clock and 6 to 12 o'clock and if the sidewall to sidewall bulge dimention (I forget what the tire people call it) will clear lock to lock both ways. then if it looks good in your wheelwell.

When I installed the new rims on my 68 Charger I had to change the wheel studs to 9/16 x 18 and they are also significantly longer than stock due to the wheels being so much thicker. I went with the circle racing billet magnum 500s. 17x8 front and 18x9.5 rear.

Section Width

R.

I run 17s on the front and 18s on the rear of my Super Bee, and my personal opinion is that our old Mopars need to be lowered a bit to look best with 17 or 18 inch wheels and tires. I dropped mine approximately 2".

Also, make sure that you run a tall enough tire on the rear to fill up the wheel well. There are actually not that many 18 inch tires that are both wide AND tall enough to fill those huge wheel wells.

I agree. I have room for a 275 wide tire that is pretty tall on my Newport. All I have found so far is very spendy or a drag radial.....or for a light truck.

I went 18" on my car primarily for handling and to have the clearance for big brakes. Something to look out for is if you're running factory sized torsion bars you might run into rubbing issues with larger tires up front. And you will feel more of the road, a lot more vs a 15" tire. If you're only looking at 18s for aesthetics then I would go 17" to give yourself a taller sidewall.

Thanks, after I posted I did some online research and found that 17 inch is probably what I would use if I did jump from the 15 inch size. I have to buy new tires anyway so I thought I would improve the technology a bit. I'm still not sold as I like to keep things simple though.

Did you work with American Racing? How were they?

17" tires of the proper height are going away. There are still some out there but the selection is getting slim.

When I went to 18s on the hot rod I grabbed a 295/45-18 for the rear and a matching 245/45-18 on the front. They worked great but I kinda wanted a taller tire up front.

You might want to play around with tire sizes to find something at 27" tall in the front and 28" or 29" out back for a typical hot rod.

As Feets mentioned, stick with tall tires, or as tall as you can get away with.

I worked with AR through a local tire dealer. It was very easy. I researched a bit first to understand the pretty simple form you fill out and choose wheel style. Then worked with the dealer for a test wheel in standard BS and tire size I wanted for the front... then used that as reference for final measurements. Filled out the form with the dealer and ordered the 4 wheels/tires. In a couple weeks done. I bought the "measuring" wheel/tire as a spare.

On the 17's vs 18's it depends on what type of tire you want. There a lot of nice tires in 17's. If you go low profile ultra high performance, the 17's are a little short.

Noted!

I think section width is not the issue. That tells you how wide the tire is.

Aspect ratio is a larger concern. That ratio gives you the tall or short sidewall.



section width / aspect ratio - wheel diameter

275/60-15

275 is the section width. Nice and fat.
60 is the aspect ratio. 60% of the 275 mm width.
15 is the wheel diameter.

OHHHHH....

This is good info.

What about backspacing? and bolt pattern?

I'm guessing the pattern on the 74 cuda is 5 lugs x 4.5" centers.

What is my backspacing min/max spec?

I dont want to use spacers.

Thanks again.

You can use this thread as a guide, do the math on subtracting the spacers I have to figure out the backspacing. Keep in mind manufacturing variation can be pretty large on these cars, you mileage [and tire clearance] may vary.


http://www.cuda-challenger.com/cc/index.php?topic=74307.0

On E bodies we stay around 26". Usually we go 275 35 18 front and 295 35 18 rear on 18x9 or 9.5 and 18x10 rear.

I copied GoodiesGotACuda tires size, brand and spacers and I am very happy. I did not move the springs in and I have people insist that I mini tubbed it....

Perhaps performance-wise that's a good size for the rear, but 26" for the rear of an ebody is far too short for me. If aesthetics are a priority, I'd have to stick with a 28"+ tall tire. It's just too big of a wheel well for that short of a tire. In my humble opinion.