Knowing which ratio will suit your motor car best
When it’s time to overhaul, an upgraded rear axle ratio is a great way to enhance your MKVI Bentley, R type Bentley, Rolls Royce silver Dawn or Wraith. The 4 ¼ engine is very well suited to an intermediate ratio from the later R type Bentley 12/41 (3.42:1). This ratio gives lower engine revs for cruising, and also allows the torque provided by the engine to be used to far greater benefit, especially when pulling away fully loaded in 2nd gear. All in all, it will greatly improve what is already extremely good and offers approximately a 10% raise over the standard 11/41 (3.72:1) axle ratio.
The 4.5 Litre MKVI Bentley, Silver Dawn and later R type Bentley’s are well suited to the “Continental” ratio which is approximately 18% over standard. The more powerful engine copes with this ratio very well and is an excellent upgrade for cruising giving lower engine revs and improved fuel consumption with the added benefit of more useable torque within the short rev range these early post war cars have. This equates to: 54.5 mph at 2000 RPM and 69.7 mph at 2500 RPM.
The Rolls Royce Silver Wraith standard wheelbase has a ratio of 11/41 (3.72:1) and is already “geared up” with the addition of 17” wheels. Depending on the fitment of heavy coachwork, or the kind of work a limousine may be asked to carry out, we recommend keeping the car standard or opting for the 12.41 (3.42:1) intermediate ratio. Contact us to discuss your exact requirements.