I know someone must have asked this before, but what do you do to upgrade to 18 or 20" wheels for the computer? This would throw off all the readings for speedo, MPG , ETC from the message center or would it not? I know many of us have changed wheels, what did you do?
I know someone must have asked this before, but what do you do to upgrade to 18 or 20" wheels for the computer? This would throw off all the readings for speedo, MPG , ETC from the message center or would it not? I know many of us have changed wheels, what did you do?
Depends on what you get for tires. I am putting 255/45 18's on they are only about ahalf a percent different than stock. If you do change the tire diameter some of the engine tuners like the diablo sport predator will allow you to adjustthe computer for the new diameter. You also might be able to get your dealer to adjust it.
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05 vert GT premium, any color you want as long as its black, 5spd, shaker 500, 18" Chrome Bullits wrapped with KDW2s 255/45 up front and 285/40s bringing up the rear, K&N CAI, Diablosport Predator 91 Octane tune, Pioneer AVIC-D3 w/Bluetooth XM IPOD, Hireman Flaming Pony, 8" antenna, Smoked lenses all around, Webelectric sequential turn signals, Redline hood struts, Hurst short throw shifter with T-handle, Bassani off-road x-pipe and axle-backs
I know someone must have asked this before, but what do you do to upgrade to 18 or 20" wheels for the computer? This would throw off all the readings for speedo, MPG , ETC from the message center or would it not? I know many of us have changed wheels, what did you do?
The size of the rim won't require you to make any adjustments for your speedo. It's the total diameter of the wheel with the tire mounted. If you stay within .5 inches either way you shouldn't have to make any adjustments.
If your's came with 17" and Prelli's, you should be somewhere around 27" in diameter. So, if you stay somewhere between 26.5" and 27.5 you should be ok.
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Pete
05 Torch Red GT W/ White Stripes, Premium Package, Grey leather, Shaker 1000
Installed: C&L CAI, Diablo Predator, Steed Chin Spoiler, SS rear valance, Plenum cover, Steeda 3 piece Curved Billet Pedals, Steeda Billet Oil-Radiator-Power Steering Caps, Street Scene Side Window Louvers, JBA axle back exhaust, Boyd Coddington Smoothie Wheels, BF Goodrich NT G-Force Tires.
Some tire stores actually have what is called plus sizing. They will show your stock wheel/tire size and then plus sizes. What that means is if you go to a +1 on a GT mustang you will get an 18" wheel that has the same outside size as the 17" factory tire/wheel combination. +2 would give you 19". This way you don't have to worry about the effect on the speedo. You might have a slight performance decrease do to the additional wheel size.
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2005 GT Coupe Premium, Redfire, Dark Charcoal, IUP, Manual, Bullits, and active theft.
Ordered 2/21 - Serialized 4/21!
Build Week 5/16
Built 5/18
Shipped via rail car 5/21
Arrived at ramp 5/30
Arrived at dealer 5/31
Got the call 6/2
Picked up at dealer 6/4
Original Dealer Estimate 4/25
Updated Dealer Estimate last week in May first week in June
(Last GT dealer will receive)
Speedo Recalibrate For Bigger Whls? 
