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It won't be the first time a marketing department has got it badly wrong !
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Here's a quick calc, with some fairly typical fwd car data.
I've assumed that at rest, there's 70% of the vehicle's weight acting on the front axle, and that the height of the c of g is 0.4m, and that the coefficient of friction between tyre and road is 0.7.
The nubers given in the answers below are the engine torques which will cause wheelspin in each gear.
I'm not saying that a Focus RS can spin its wheels in 4th gear, but, the data I've assumed aren't so far wrong, and it probably will be relying on traction control until you get into fourth!
M=1163; % Mass (kg) g=9.81; % Acceleration due to gravity (ms^-2) mu=0.7; % Estimate for co-efficient of friction between tyre & road R1=0.7; % Estimate for static front axle proportion of vehicle load L=2.61; % Wheelbase (m) h=0.4; % Estimate for height of c of g (m) % Calculates Rolling radius for a 175/70R14 tyre (m) Rr=(14*25.4e-3/2)+((70/100)*175e-3); g1=3.73; % First gear ratio g2=2.14; % Second gear ratio g3=1.41; % Third gear ratio g4=1.12; % Fourth gear ratio g5=0.89; % Fifth gear ratio fd=3.74; % Final drive ratio Te=(Rr/(g1*fd))*(R1*L*mu*M*g/(L+(h*mu)))
Te =
108.6832
Te=(Rr/(g2*fd))*(R1*L*mu*M*g/(L+(h*mu)))
Te =
189.4338
Te=(Rr/(g3*fd))*(R1*L*mu*M*g/(L+(h*mu)))
Te =
287.5094
Te=(Rr/(g4*fd))*(R1*L*mu*M*g/(L+(h*mu)))
Te =
361.9538
Te=(Rr/(g5*fd))*(R1*L*mu*M*g/(L+(h*mu)))
Te =
455.4925
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Hmmmmm... wheelspin at will in fourth.... drool....
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Did anyone see Clarkson's old programme about Hot Hatches on Dave?
Ford has form for bringing out high performance cars just when the economy tanks....
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