Whats the biggest rims and tires I can fit under a 65 malibu's rear wheel wells. Also what backspacing

The rear rim width can be either a 7" with 4.5" backspacing or an 8" with 5" backspacing to place it in the center of the wheel well. Stick with a 26" diameter tire/wheel combo to stay close to the original sizing. I have 255/45R17 tires on the 17" rims, these are 26.04" in diameter. I have 1" clearance on the outside without rolling the wheel lip and 3/4" on the inside. Excellent fit on rear. You might be able to go with a 275 width, but you most likely will rub during cornering.

You should definitely check the condition of your rear suspension bushings. I'd replace them first before putting wide tires on. A sloppy rear suspension will tear up your tires if it allows the tires to rub.

The front rim width should be a 7" with 4.5" backspacing. I have 8" with 5" backspacing, but if I did it over, I would go with the 7" width. The tire is close to the outside edge of the wheelhouse, the 7" would bring it 0.5" inward away from the outside edge. I have 235/45R17 tires on the 17" rims, these are 25.32" in diameter. I also have 1" drop springs, no problems under normal driving conditions. Minor rubbing when the front wheel is pushed up into the wheel house at full turn lock; such as backing out of a driveway with only two wheels supporting most of the vehicle.


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Brian TC#1092, ACES#4374
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1964 Malibu SS Convertible (http://www.chevelles.com/showroom/65elcamino64.jpg) (Garage Queen) Before Restoration (http://www.chevelles.com/showroom/65elcamino64a.jpg)
1965 El Camino (http://www.chevelles.com/showroom/65elcamino1b.jpg) (Daily Driver) Before Restoration (http://www.chevelles.com/showroom/65elcamino1a.jpg)
1981 Corvette (http://www.chevelles.com/showroom/65elcamino81.jpg) (Sidelined for repairs)