Tyres are the Midget's only contact with the road surface, and the correct specification affects handling, braking, ride comfort, and speedometer accuracy. The standard Midget tyre size is 145/80R13 (also marked as 145SR13), which fits all original 4-inch steel and wire wheels.
Early Mk1 cars were originally supplied on crossply tyres, but modern radial tyres in the correct size are a universal improvement and should be fitted to all four corners, mixing radial and crossply tyres on the same axle is both dangerous and illegal in the UK.
Wider Tyre Options
A wider 155/70R13 tyre is a popular alternative, offering a broader contact patch for improved grip in both dry and wet conditions. The lower 70-series profile compared to the standard 80-series gives a slightly sportier appearance and marginally sharper turn-in response.
However, the reduced sidewall height means the overall rolling diameter is slightly smaller, which lowers the ride height fractionally and causes the speedometer to over-read by a small amount. Wheel and tyre packages combining alloy wheels with 155/70R13 tyres pre-fitted are available, providing a matched set with the correct offset for the Midget.
Inner Tubes and Valves
Wire wheel cars require inner tubes, as the spoked wheel construction is not airtight. The inner tube must be the correct size for the tyre and should be lightly dusted with talc before fitting to prevent it bonding to the inside of the tyre casing. Steel wheel and alloy wheel cars use tubeless tyres and do not require inner tubes. Tyre valve types differ accordingly, rubber snap-in valves for tubeless steel and alloy wheel applications, and metal screw-in valves for tubed wire wheel rims.
Tyre Fitting Considerations
When fitting wider tyres, wheel arch clearance should be confirmed, particularly on lowered cars where reduced suspension travel brings the tyre closer to the inner wing. On cars fitted with wider-than-standard alloy wheels (5-inch or 5.5-inch rim width), a correspondingly wider tyre is appropriate, the tyre width should be matched to the wheel rim width to ensure the correct tyre profile and proper sidewall support. Tyre pressures differ between front and rear and between solo and laden driving, the correct pressures for the specific tyre size and vehicle loading should be confirmed before use.