Q & A Jaguar World's technical advice service

Edited by Ray Ingman

X308 – X350 Compatibility

Q I have owned an X308 for six years and have become addicted to the Jaguar marque, so I have just purchased an X350 to replace it. Before disposing of the earlier car, I have two questions: Will the wheel rims from my 308 (Daimler version) fit onto the 350?

In addition, will the CD changer from my old car fit in the replacement, or will I have to buy a new one? I realise the latter question may seem a little outdated, but I do own a vast CD collection and really don’t get on with music streaming and similar modern affectations!

ANo in both cases! – Perhaps we should have broken that news a little more gently, so to explain further: The primary reason that the wheels will not interchange is the stud pattern. With the 1955 introduction of the 2.4/3.4 compact saloons (retrospectively known as the ‘Mk1’), Jaguar adopted a ‘5 x 4.75inch’ standard. Translated this means five studs arranged in a circle measuring four and three quarter inches, this is widely referred to as the PCD or Pitch Circle Diameter.

This pattern was employed on ‘bolt on’ wheel variants up to and including the XK8 (X100) and X308 saloons. The exceptions to this rule were initiated by launch of the Ford inspired 1999 S-Type and 2001 X-Type models, unsurprisingly both adopting the metric 5 x108mm pattern favoured by the then parent company. The final demise of ‘5 x 4.75’ (or somewhat clumsier ‘5 x 120.65’ in metric parlance) coincided with the arrival of the XK (X150) and X350 saloon ranges, both favouring the smaller PCD.

However, PCD is not the only factor inhibiting wheel/tyre swappery. Even if the wheel will physically attach to the car, it must be ensured that the width and diameter do not cause any fouling issues with the bodywork, suspension or brake system. This should be checked both statically and with full suspension and steering deflection applied.

Finally, the rolling radius of the tyre should be similar to the original fitment. If not, gearing will be affected – the most obvious manifestations of this being incorrect reading of the speedometer (and consequently, cruise control).

As to the CD changer, it is a fact that the world of ICE development inexorably moves on apace, the old unit is simply incompatible with the newer system. At least you didn’t ask how to fit an eight-track player!.