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Corvette Sawblade spacer adapter thickness - 240


Bored Member
Oct 21, 2010
Chester co, PA
I took some measurements, read some threads, but before I spend the duckits I'd like to halfway confirm what thickness I think I need to fit corvette sawblades on a 242. Specs on the sawblades are 17" diameter, 8.5" wide front, 9.5" wide rear, ET56 for both. I want to run 235/40/17 tires, but may want to go wider in the back in the future. Fender / quarter panel modification is not a concern, I just don't want to rub on the inside. I think the car is at stock height, I don't know what springs are on the car but they don't look cut. I will eventually lower it, I am undecided by how much but not slammed, so maybe 1-2".

I think I need 44mm in the front and 51mm in the rear. If you have any experience with fitment I'd like to hear it.

Your numbers are good.

You can aim for 10-13mm offset up front.

For reference, on a 17" wheel:
9" ET7 will clear inside
or on 8.5", ET13.
or 8", ET20

As the wheel width goes down, the offset can go up to maintain the same backspacing.

9.5" ET0 will work on the rear to clear the inside with the axle centered. I think ET5 would also fit, but if you're OK pulling the quarters to fit 245-255+ tires, then I'd go with 0mm.

On my car I used 9.5" ET3 with 275 width Hoosier A6 that are much wider than a street tire. They rubbed a little on the inside until I hammered the inside and ground down the flange on the trailing arm. The same width/offset would have been fine with a street tire.

9.5" ET0 (probably a 245 tire, I don't remember, Rob's 242 drift car):
Wheel back spacing is important on the front. Stock back spacing with 15x6 wheel is 4.5 inches.
It should be closer to 4.16-4.29". A 6" wheel will measure close to 7" overall width. 0mm offset would yield ~3.5" backspacing. Add 20mm offset offset of a Virgo, and it's around 4.25" backspacing.

A 17" wheel can fit with greater backspacing than a 15" wheel because of how the strut angled away from the wheel.
Thanks for the help and the numbers Towery.
I'll be going with ET10 front (46mm spacer) and ET0 (56mm spacer) in the rear in case I want to go wider with the tires in the future and will make the fender mods as needed.