Spitfire
Stock
Tire/Wheel Info

Mk1

MkII

Mk3

Mk 4

1500

stock wheels

13 x 3.5" D
steel

13 x 3.5" D
steel

13 x 3.5" D up to FM 75000
13 x 4.5"J after

13 x 4.5" J
steel

13 x 4.5"J: up to 1979*
13 x 5" J: 197980

offset

?

?

?

+0.5"

+0.5"

tires

5.20S x 13" Dunlop C41

5.20S x 13" Dunlop C41

5.20S x 13" Dunlop C41

5.20S x 13" Dunlop C41
145SR13 radial

155SR x 13 Dunlop SP68 or Goodyear
G800

optional factory wheel

13 x 4.5" J
wire wheels

13 x 4.5" J
wire wheels

13 x 4.5" J
wire wheels

13 x 4.5" J
wire wheels

n/a

optional factory tires

5.20  13"

1.45SR x 13 radial Dunlop SP41

5.20S  13"
1.45SR x 13 radial Dunlop SP41/SP68

1.55SR x 13 radial Dunlop SP68 or
Goodyear G800

n/a

tire pressure front

18 lb/sqin

18 lb/sqin
21 lb/sqin (optional tires)

18 lbf/in (cross ply)
21 lb/sqin (radial)

21 lb/sqin

21 lb/sqin

tire pressure rear

24 lb/sqin

24 lb/sqin
26 lb/sqin (optional tires)

24 lb/sqin (cross ply)
26 lbf/in (radial)

26 lb/sqin

26 lb/sqin

lug circle diameter

3.75"

3.75"

3.75"

3.75"

3.75"

offset 
probably +0.5" 
probably +0.5" 
probably +0.5" 
+0.5" 
+0.5" 
lug nut

3/8" UNF

3/8" UNF

3/8" UNF

3/8" UNF

3/8" UNF

lug nut torque

3848 ft# (5.26.6 kgf/m)

3848 ft# (5.26.6 kgf/m)

3848 ft# (5.26.6 kgf/m)

3848 ft# (5.26.6 kgf/m)

3848 ft# (5.26.6 kgf/m)

wheel weight

let
me know

let
me know

let
me know

let
me know

18lbs. each

*In 1976 only, US Spitfires shared wheels with the
Austin Marina. The wheels were 13 x 4.5" and had
"square
holes"
GT6
Stock
Tire/Wheel Info

Mk1

MkII & GT6+

Mk3

stock wheels

13 x 4.5" J
steel

13 x 4.5" J
steel

13 x 4.5" J
steel

offset

+0.5"

+0.5"

+0.5"

tires

155SR x 13 Dunlop SP68 or Goodyear
G800

1.55SR x 13 radial Dunlop SP41/SP68
(Mk2), Goodyear G800 (+)

5.20S x 13" Dunlop SP68

optional factory wheel

13 x 4.5" J
wire wheels

13 x 4.5" J
wire wheels

13 x 4.5" J
wire wheels

optional factory tires

155SR x 13 Dunlop SP68 or Goodyear
G800

1.55SR x 13 radial Dunlop SP41/SP68

Dunlop SP68

tire pressure front

20 lb/sqin

24 lb/sqin

24 lb/sqin

tire pressure rear

24 lb/sqin

28 lb/sqin**

28 lb/sqin

** According to a Jan. 1969 Triumph Service
Bulletin the tire pressures for the GT6+ using
155SR13 G 800 Goodyear tires were revised as
follows: Front24 psi and Rear30 psi
Today currently available size close in diameter
to the original "5.20S 13" (ie, keeping
transmission ratios and speedo accurate) is 155 SR
13 (or 15513, or 1558013 as the 80 means the
height/width ratio of the tyre, 80 is the "normal"
ratio, not mentionned means 80)
175/70/13 would have the same overall wheel
diameter (same transmission ratio)
Note: Do you have a vibration that feels like a tire out of balance but doesn't go away no matter how many times your balance them? It might be your drive shaft is out of balance. Drive shafts came from the factory balanced with little weights that are often knocked off. Call you local "hot rod" or 4x4 shop for suggestions to who can balance it again.
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