Correct Tire Size Ratio for Murcielago AWD

The Murcielago has two optional front tire sizes, which creates an over/under for tire size ratio from front to rear. If an incorrect tire size is installed, the center differential (vicious coupler) will be damaged. Below are the calculations for finding the correct tire size ratio on a Murcielago, LP640, or LP670. 

Note, that every tire is different, A Pirelli 335/30R18 tire is a different size than a Michelin 335/30R18 tire. You MUST measure their actual size. You can find the tires' actual height on Tire Rack, then see if the difference falls within the threshold. 

Actual diameters of the stock 18” tires: 
Pirelli P-Zero 235/35R18 Overall Diameter - 24.4764"
Pirelli P-Zero 245/35R18 Overall Diameter - 24.7520"
Pirelli P-Zero 335/30R18 Overall Diameter - 25.9134"

Variances in height of stock wheels and tires:
235/35R18 with 335/30R18 = 1.437008"
245/35R18 with 335/30R18 -1.161417"
Threshold: 1.161417" to 1.437008" difference in size 

For example of how to find the correct tire, here are the ratios for the Michelin SS tire in a 19" size:

Rear: 345/30/R19 - 27.2"
Front: 235/30/R19 - 24.6"
Difference = 2.6" - too tall

Rear: 345/30/R19 - 27.2"
Front: 235/35/R19 - 25.5"
Difference = 1.7" - too tall

Rear: 345/30/R19 - 27.2"
Front: 235/40/R19 - 26.4"
Difference = .08" - too short

Rear: 345/30/R19 - 27.2"
Front: 245/35/R19 - 25.8"
Difference = 1.4" - WINNER!

Another option if you want to run a specific tire or wheel that doesn't fit within the stock ratio, you can convert the car to RWD. For more information regarding RWD conversions, please email me HERE.