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-=Jeff=- · 09-18-2011

still free for basic stuff

going from the 315/35R17 on a 17x11 to a 335/30R18 on a 18x12 diameter goes from 25.7 to 25.9

Speedo would be off by 1% at 60 so it would read 60 but actual is 60.6.

If Dom's rear tire is a 325/30R19 on a 19x12 then his Dia is 26.7 and according you the link WVZR-1 posted it is a 4.2% speedo offset. So when the Speedo is showing 60 it will actually be 62.5.

So I am not sure where the 12-15% is exactly

09-18-2011	#6
-=Jeff=- Join Date: Jul 2007 Location: Bartlett, IL Posts: 7,131	Re: Contemplating Rear Gear change still free for basic stuff going from the 315/35R17 on a 17x11 to a 335/30R18 on a 18x12 diameter goes from 25.7 to 25.9 Speedo would be off by 1% at 60 so it would read 60 but actual is 60.6. If Dom's rear tire is a 325/30R19 on a 19x12 then his Dia is 26.7 and according you the link WVZR-1 posted it is a 4.2% speedo offset. So when the Speedo is showing 60 it will actually be 62.5. So I am not sure where the 12-15% is exactly __________________ 1990 Corvette ZR-1 #1051 Watson Headers (2" Primary) - 3" Magnaflow Bullet cats - LT4 Catback Late Model IH - Plenum Coilovers - 4.10s Custom Interior NCM Lifetime Member #978