I read your article about spindle swaps for the 1964-67 Chevelle. I’m using 1994 Impala spindles and CPP control arms. You suggest that I can use a larger aftermarket wheel? Does it pull the wheel back into the car and if so how much?

In other words, if my car has a wheel that is too close to the outside, will it bring it inboard? And by how much?

D. L.

The taller spindle doesn’t really affect what you’re asking about except that with a smaller 14 or 15 inch diameter wheel that uses a deeper offset, the inside edge of the rim will hit the steering arm. This is why larger than 15 inch diameter wheels are required with those taller spindles.

If I read between the lines on your question, I think what you’re really asking concerns wheel backspacing. This is a spec most wheel companies offer in the descriptions of each wheel. It is the distance from the inside wheel mounting pad to the inner lip of the wheel. This dimension establishes where the tire mounts in the wheel well with a direct effect on clearance for larger tires and wider wheels. This backspacing dimension is often overlooked when ordering wheels yet plays a huge role in fitting wider wheels and tires under older cars. 

Wheel Backspace: The distance from the inside wheel mounting pad to the inner lip of the wheel. 

Most standard offsets will place the wheel mounting point roughly in the center of the width of the wheel. As an example, if using an eight inch wheel, a zero offset wheel will measure four inches from the wheel mounting pad to the inner lip. You can easily measure your wheels with a straightedge across the inner wheel lip and use a tape measure to determine the actual distance to the wheel mounting pad.

This is the backspacing dimension.

Measuring wheel backspace is easy. Place the wheel face down on the shop floor. I use a length of steel that is cut to fit inside the lip of a given 17 or 18 inch wheel. Then we just measure from the edge of the angle iron to the wheel mounting face. In this case, it’s 4-1/4 inches on this 17 x 8 inch wheel. (Image/Jeff Smith)

Sometimes companies will measure backspacing to just below the lip, while others include the small lip, so you will need to determine which way they measure their wheels and then duplicate that procedure to be the most accurate. The difference is usually around 1/8 inch, but still important to note.

For an early Chevelle with taller spindles, you can squeeze a 17 or 18 inch diameter wheel that is 9 inches wide with 5-3/4 inches of backspacing. That pulls the tire inboard and should clear everything (depending upon ride height). Often, the inner sidewall will rub on the sway bar at full steering lock but the only time you will experience this is during parallel parking. If you avoid full lock when turning, this will minimize damage to the wheel or sidewall. The above recommendation is difficult to achieve because very few wheel companies sell a wheel with 5-3/4 inch backspacing.

My personal package is on a ’65 Chevelle with Global West tubular upper control arms on the front. With those components, I can fit an 18 x 9-1/2 inch wheel with a six inch back spacing with no tire rubbing on the front fender wells.

That wheel dimension won’t work if you are using upper control arms from any other company because they are all a little bit different in length. For example that above six inch backspacing will rub on a Hotchkis upper control arm but it will clear a Global West arm. I’ve never tried a Classic Performance upper control arm so I can’t comment. 

The best way to know if a given 18 x 9-1/2 inch wheel with a 6 inch backspacing wheel with a 275/40ZR18 tire package will work is to find a friend with one of these wheels with a mounted tire you can test fit it on your car.

Quite frankly, the first time I saw this tire and wheel package was on my friend Scott Gillman’s big block ’65 Chevelle wagon nearly 25 years ago. I didn’t believe him when he said it would fit under my car. I bet him that tire and wheel would rub on my car and offered to buy dinner if I was wrong.

I bought dinner that night!

Then the next day I went out and found a set of (back then, 16 inch wheels were big) and bought a set of 16 x 9-1/2 inch wheels with a six inch backspacing and, with 275/50R16 tires, they bolted right on for all four corners. I now have the larger 18 inch wheels with the same backspacing and they fit even better.

Hope this helps.

You may also appreciate this article from Jeff Smith: Suspension Upgrade Tips for Early Chevelles (and other A-Bodies)

Keywords
Ask Away, backspacing, Jeff Smith, Spindles, wheels
Share this Article
Author: Jeff Smith

Jeff Smith has had a passion for cars since he began working at his grandfather's gas station at the age 10. After graduating from Iowa State University with a journalism degree in 1978, he combined his two passions: cars and writing. Smith began writing for Car Craft magazine in 1979 and became editor in 1984. In 1987, he assumed the role of editor for Hot Rod magazine before returning to his first love of writing technical stories. Since 2003, Jeff has held various positions at Car Craft (including editor), has written books on small block Chevy performance, and even cultivated an impressive collection of 1965 and 1966 Chevelles. Now he serves as a regular contributor to OnAllCylinders.