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Torque steering is the influence of engine torque on the steering, especially in front-wheel drive vehicles with transversely mounted engines. For example, during heavy acceleration the steering may pull to one side, which may be disturbing to the driver. The effect is manifested either as a tugging sensation in the steering wheel, or a veering of the vehicle from the intended path. Torque steer is directly related to differences in the forces in the contact patches of the left and right drive wheels. The effect becomes more evident when high torques are applied to the drive wheels either because of a high overall reduction ratio between the engine and wheels,〔(【引用サイトリンク】title=Theory of Ground Vehicles, 4th Edition )〕 high engine torque, or some combination of the two. Torque steering is distinct from steering kickback. == Causes == Root causes for torque steer are:〔(【引用サイトリンク】title=Torque Steer Influences on McPherson Front Axles )〕 * Incorrect sidewall ply design allowing deformation of the tire sidewall.〔(【引用サイトリンク】title=Car and Driver 2005 Pontiac Grand Prix GXP )〕 * Asymmetric driveshaft angles due to any combination of * * Unequal driveshaft length or diameter * * Transient movement of the engine * * Tolerances in engine mounts * * Body roll * * Single wheel bump * Different driveshaft torques left to right (due to wheel bearing or differential problems) * Suspension geometry tolerances * Unequal traction forces due to road surface (µ-Split) in combination with kingpin offset The problems associated with unequal length driveshafts is endemic to the transverse engine layout combined with an end mounted transmission unit; some manufacturers have mitigated this completely by mounting the engine longitudinally but still driving the front wheels - this indeed was the solution adopted on the earliest front wheel drive Citroens. Early Renault front driven models such as the R4, R5 Phase I R12, R18 and certain R21 models also adopted this layout, as does Audi to the present day in its midsize models upward. The key disadvantage is packaging; in the case of Audi, which mounts the power unit ahead of the front axle line, this compromises handling by going against the perfect 50:50 weight distribution. This configuration does however facilitate the easy addition of all wheel drive - Subaru also uses the overhung longitudinal engine for the same reason, but mitigates the problem of unbalanced centre of gravity by using a "flat-four" boxer engine. Renault, on the other hand placed the engine ''behind'' the front axle line, but this compromises interior packaging since it forces the engine further back towards the firewall. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Torque steering」の詳細全文を読む スポンサード リンク
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