The 'torque' thread rises again... The math is actually simple and will answer all your questions about length of extensions. It goes this way: T = Torque needed at the bolt A = Applied torque of the wrench L = length of the torque wrench E = length of the extension A = (T * L) / (L + E) --bob '86 5KS Avant '02 TTQR '07 Q7 4.2