From Citroen SM Wiki
  • 2.7L carburettor cars shipped with 195/70 tires
  • IE and 3.0L cars shipped with 205/70 tires (effectively all later cars).
    • An owner's opinion: a bit over-geared.
  • 205/65 fits (and clears wheel spats), and (Owners opinion) improves acceleration and driving experience, at the expense of higher cruise RPM.
  • 215/65 is the best choice as it adds a little grip and has a VERY close rolling diameter to the original thus retaining the original gearing.

ALL 65 section tyres reduce the ride comfort slightly.

  • Candidate Tires
      • Original equipment, available to special order- Michelin 205.VR.15.XWX
      • Very nice -- Brucem (and others)
    • Continental Barum (205/65, at least)
    • Pirelli P4000, no longer available as of 1/09 (if not earlier)
    • Michelin Energy 205/65 the original for the XM works fine for me.

Longstone Classic Tires sells Michelin XWX for the SM. Prices, while not cheap, include worldwide shipping.

See also: Wheels