The crown wheel and pinion (CWP) ratio is one of the main variables controlling the overall gearing on a rear wheel drive car, which means that changing it has a significant effect on a vehicle’s performance.

It’s extremely important to select the optimal ratio suited to engine characteristics and vehicle speed requirements, whether it’s for a road-based trackday car or an outright competition machine that requires fine tuning of performance from circuit-to-circuit.

This is why leading high performance automotive drivetrain manufacturer Quaife Engineering is already experiencing strong demand for the Tran-X crown wheel and pinion (CWP) ratio sets, designed for the ‘English’, ‘Atlas’ and Sierra 7in axles as fitted to numerous popular rear wheel drive Ford and Ford-based cars.

The Tran-X by Quaife crown wheel and pinion sets for the Ford axles are precision engineered from high tensile steel billets and are Manganese Phosphate coated for added wear resistance. Full details on the Tran-X by Quaife crown wheel and pinion range are as follows –

Tran-X by Quaife CWP for Ford English Axle

CWP Ratios: 3.545:1, 3.777:1, 3.889:1, 4.111:1, 4.444:1, 4.714:1, 4.857:1, 5.143:1, 5.286:1

Retail price – £300 inc VAT

Tran-X by Quaife CWP for Ford Atlas Axle

CWP Ratios: 4.111:1, 4.375:1, 4.625:1, 4.875:1, 5.143:1, 5.375:1, 5.857:1

Retail price £324 inc VAT (4.625:1 and 5.143:1 ratios)

Retail price £535.20 inc VAT (all other Atlas ratios)

Tran-X by Quaife CWP for Ford Sierra 7″ Axle

CWP Ratios: 3.62:1 and 3.92:1

Retail price £300 inc VAT

CWP Ratios: 4.111:1, 4.444:1 and 4.714:1

Retail price £535.20 inc VAT

CWP Ratios: 3.14:1* and 3.38:1*

*These are pre-used original Ford units.

Retail price £360 inc VAT

To assist customers with the Tran-X by Quaife CWP selection process, Quaife has developed a speed calculator program, which downloads in seconds from

Once installed, users enter key data on their car’s engine speed, gearing, wheel and tyre circumference into the relevant sections and the Quaife Speed Calculator works out the optimal choice of CWP ratio for individual needs.

More information from 01732 741 144 or ENDS.