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Posi vs wheel diameters side to side

Posted: Sat Apr 07, 2018 7:49 pm
by camrat68
I'm running non-stock tire widths on 20" Camaro wheels that have a .3 difference in diameter front to rear. While this isn't enough to set off the ABS, is it enough to damage the LSD running that difference side to side in the rear?

I'm getting ready to take a long trip in June and I'm debating whether it's worth taking the full-sized spare since I'm not running the stock sized tire/wheel combo. We do have AAA but I prefer to be self-reliant.

Jim

Re: Posi vs wheel diameters side to side

Posted: Sun Apr 08, 2018 11:26 pm
by Navy Lifer
Jim, I'm not sure I understand the premise of your scenario--are you suggesting there might be a situation or reason where you'd have a (smaller) front tire on the rear, or as a matter of a (smaller?) spare going on in place of a larger rear tire for an extended period of time?

The comparable situation, as I think about it, is the Chevy SS sedan--the front & rear tires are not the same size, and the spare is a "front"--OE 19x8.5 and front tire - 245/40-19. The rear tires are 275/35-19. Tire diameters are 26.7 front and 26.5 rear, or 0.2" overall. Difference is less than 1%--in a situation where the spare (if equipped) ends up installed on the rear, the difference in revolutions per mile is 778 front vs 783 rear, or just 5 total revolutions "side-to-side". An incorrectly-inflated tire could account for a greater difference than that.

So, to answer the question....if I understand it correctly...the difference is probably not enough to harm the differential.

Re: Posi vs wheel diameters side to side

Posted: Mon Apr 09, 2018 8:11 pm
by camrat68
That answered my question, Thank You.

Jim