Posi vs wheel diameters side to side

Discussion on wheel & tire issues
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camrat68
Posts: 163
Joined: Mon May 01, 2017 12:47 am
Location: Appleton, WI

Posi vs wheel diameters side to side

Post by camrat68 » Sun Apr 08, 2018 12:49 am

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
Jim Chesnutt
1968 Camaro -my first car.
1995 Black/White 9C1 Caprice
2012 Alto Gray Metallic 9C1 Caprice--The HoDag-Solo axle back exhaust, improved racing OTR CAI intake.
2013 Black/White 9C1--NADACOP-Stock. For now......

Navy Lifer
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Location: Canton GA

Re: Posi vs wheel diameters side to side

Post by Navy Lifer » Mon Apr 09, 2018 4:26 am

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.

camrat68
Posts: 163
Joined: Mon May 01, 2017 12:47 am
Location: Appleton, WI

Re: Posi vs wheel diameters side to side

Post by camrat68 » Tue Apr 10, 2018 1:11 am

That answered my question, Thank You.

Jim
Jim Chesnutt
1968 Camaro -my first car.
1995 Black/White 9C1 Caprice
2012 Alto Gray Metallic 9C1 Caprice--The HoDag-Solo axle back exhaust, improved racing OTR CAI intake.
2013 Black/White 9C1--NADACOP-Stock. For now......

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