18x8 coys on 79 cutlass

[Pro-Touring79Cutlass]

im looking at 18x8 coys c-5s on my olds ,or 17x8 i had posted before for the 17x8 and i had been told that a 4.5 inch backspacing would fit ,i was looking at the coys and the 18x8s are only 50 bucks more than the 17x8s what backspacing would i need and any sugestions on what size tire to run on the 18s

[HELLCAMINO]

You sort of answered your own question. If you were told that the 17x8 with 4.5bs would fit, then i don't see why the 18x8 with 4.5bs would not? Keep in mind, even though the wheels are only $50 more each.......tires are about $80+ more each compared to 17's. I'm thinking a 255/40 or 45 series might fit best on an 8" rim under your ride. You could try a 275/40........but that would push it for that rim size. I have those on my new Boss 338's that are 18x9.5.

[JJEH]

I would go with the 17".

I had 7.5 with 225/45 and 8.5 with 245/40 on my MB S202 and it was nearly pefect.
To me, this combination is the best mix of performance and comfort.



If you go with 8" all around you do nothing wrong...

[67rally]

You sort of answered your own question. If you were told that the 17x8 with 4.5bs would fit, then i don't see why the 18x8 with 4.5bs would not?

x2

Going from a 17x8 to an 18x8 rim of the same width will require the same amount of backspacing.

If you were going with a wider rim, like going from 17x7 to 17x8 or 18x8, then you would need more backspacing. In this case you would go from 4.5 to 5" of bs.