My new tires have a diameter of 28.1" (285/45/18)... stock tires are 28.45".

Should I get my ECU recalibrated for this small change? The shifting doesn't feel right since I changed tires...

Thanks,
Dreamin

 

Your current tires rotate 717.788 times per mile, the stock tires rotate 708.849 times per mile, a difference of 1.26% (fast).

Not sure about L's but 99 Cobra owners report problems with traction control with that much of a difference between front and rear tires, ie the computer thinks there is a loss of traction with the wheels turning at a faster rate, and kicks in the traction control.

Rex

 

Highly unlikely you will have any problems. Those that have gone with bigger tires 30.5-31.5 have experienced no problems other than speedo being off. Tire rack recommends staying within 4% which you are well under. I posted the same question about recaling for tire diameter and could find noone who could do it including Ford.
noelvm

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99.5 Red Ligntning, Mobil 1, PRO-M 80 MM MAF/filter, Custom Superchip, Eldebrock 5512 muffler, MT ET Streets, best time (1/8) 8.44, Bugflector II, G&H Lens covers head & fog, 200 WT Pioneer 4 CH AMP, BOSE 301 SERIES IV SPEAKERS (IN BACK)
70 Vette LS-6 454 (gathering dust in the garage)

 

Sal can compensate for different tire diameters on his PSP chip.

 

by the time I got a chip from Sal, I'd probably have my new 2002 Lightning.


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99.5 Red Ligntning, Mobil 1, PRO-M 80 MM MAF/filter, Custom Superchip, Eldebrock 5512 muffler, MT ET Streets, best time (1/8) 8.44, Bugflector II, G&H Lens covers head & fog, 200 WT Pioneer 4 CH AMP, BOSE 301 SERIES IV SPEAKERS (IN BACK)
70 Vette LS-6 454 (gathering dust in the garage)