Original English wheels (steel) 3½" x 13 with no safety bead.
Original Australian wheels (steel) 4" x 13 with single safety bead.
Original English and Australian wire wheels 4½" x 13 with no safety bead.
Original tyres 620 x 13 cross plys
The original radials had a size of 145 x 13 which are now very rarely used.
155/80 x 13 are a more common size and work OK on 4" and 4½" rims.
The other common sizes that are used are 165/75 x 13 and 175/70 x 13, but are more suited to
5" rims.
5½" rims and 175.70 x 13 tyres are at the limit for registration purposes as they almost protrude out too far at the front.
MKIV & 1500 Spittys are a different situation because the quarter panels are flared out much wider and have a different wheel tyre combination, starting with 4½" rims and finishing up with 5" rims, but still no safety rims with 145 x 13 tyres on early MKIV's finish up with 155 x 13 (usually Goodyear).
For me a 13" rim 5½" wide with 175.70 x 13 tyres is the best all round combination with plenty of clearance. The best rim offset is 18mm - 25mm positive.
My Spitfire MK1 has 155/80 x 13 tyres.
The MKIII Spitfire has 175/70 x 13 on 5½" rims.
The 1500 is the same as the MKIII.
Tyre sizes and diameters that could be fitted to Spitfires:
| Size | Diameter |
|---|---|
| 620/13 | 578 |
| 145/80 x 13 | 566 |
| 155/80 x 13 | 578 |
| 165/75 x 13 | 578 |
| 175/70 x 13 | 580 |
| 185/65 x 13 | 570 |
| 185/60 x 13 | 552 |