CMP trucks
have the following wheel & tyre size combinations:
|
Wheel Size
|
Wheel Type
|
Tyre Size(s)
|
Tyre Types
|
|
6.00x13"
|
split rim
|
9.00-13
|
R.F. (Run Flat)
Pneumatic
|
|
6.00x16"
|
split rim
|
9.00-16
9.25-16
10.50-16
|
R.F. (Run Flat)
Pneumatic
|
|
6.00x20"
|
split rim
|
10.50-20
|
R.F. (Run Flat)
Pneumatic
|
Source:
Chev
CMP specifications and Ford
CMP specifications
This page will
focus mainly on the 9.00-16 tyres Dunlop T24 Trak Grip tyres as used on
the 15-cwt series of CMP trucks.
The Dunlop
T24 tyre came in three types during WW2:
-
cross country;
-
run flat: with
alternate length sidewall lugs, T24 with wartime dates generally have the
recessed bar faces;
-
"pneumatic" or
general purpose type: with more rounded shoulders.
All had a 5º
bead angle.
T24
Run Flat
| |
|
Shown
here is a Dunlop T24 Trak Grip run flat tyre. It has a heavy tread with
sidewall lugs. (Variations seen have every other sidewall lug longer than
its neighbour, or lugs with a hollow recess on the vertical face.)
This is a
post-war tyre, manufactured for the Daimler Ferret Scout Car, but it is
very similar to the wartime tyres as fitted on CMP trucks.
Photo courtesy
of Richard Notton. |
|
|
The
side is clearly marked 9.00-16 and the tyre is meant "TO FIT 6.50 H RIMS
ONLY".
6.50 stands
for the width of the rim in inches - note the 16" CMP rim is 6" wide!
The meaning
of "H" is unknown.
Photo courtesy
of Richard Notton. |
|
|
"R.F.H.S.2" denotes
this is a tyre for the Ferret Scout Car. Could it stand for "Run Flat High
Speed"?
The marking melted in the side is
likely to be the manufacturing date, July 1969.
Photo courtesy
of Richard Notton. |
|
|
The side wall is 4"
thick, this is what prevents to tyre to collapse when the air pressure
is diminished.
Photo courtesy
of Richard Notton. |
T24
Pneumatic
|
|
Here is another Dunlop
Trak Grip tyre, a pneumatic (as in non-run flat) type. Note the tread bars
do not run along the side as far as on the run flat type shown above.
This type of tyre was fitted postwar
to many British army vehicles like the Bedford MW and early Land Rover
1 tonne trucks.
Photo courtesy
of Dennis Schneider. |
|
|
|
Again,
the side is clearly marked 9.00-16 and the tyre is meant "TO FIT 6.50 L
RIMS ONLY". Other markings include "6 PLY RATING" and "MADE IN GREAT BRITAIN".
Richard
Farrant notes "6.50 L rims are wellbase,
i.e. one-piece, and are as fitted to the Land Rover 1 Tonne (101), the
tyres for these were 6 ply".
Photo courtesy
of Dennis Schneider. |
|
|
|
This
picture clearly shows the typical Dunlop Trak Grip tread pattern.
Photo courtesy
of Dennis Schneider. |
|
Simex
ST24/SA24
(link
to picture source)
|
Simex, a Malaysian subsidiary of
Dunlop, manufactures a range of Tractor Steering Wheel Tyres. The
ST24 or SA24 comes in 9.00-16 and the tread pattern is (practically) identical
to the pneumatic Dunlop T24 shown above. The table below gives the technical
characteristics of the SA24:
|
PATTERN
|
SIZE
|
RIM
WIDTH
CODE
|
DIMENSIONS
|
PATTERN
DEPTH
|
LUGS
PER
SIDE
|
PLY
RATING
|
LOAD
CAPACITY
|
MAX.
INFLATION
PRESSURE
|
MAX.
SPEED
|
OVERALL
DIAMETER
|
OVERALL
WIDTH
|
|
-
|
-
|
-
|
(mm)
|
(mm)
|
(mm)
|
(pcs)
|
-
|
(kg)
|
(bar)
|
(kph)
|
|
SA24
|
9.00-16
|
6.00
|
935
|
231
|
17.5
|
36
|
6
|
900
|
2.30
|
30
|
|
8
|
1090
|
3.10
|
30
|
|
10
|
1250
|
3.90
|
30
|
|
Other
9.00-16 tyres
Mike Kelly
made a list of 9.00-16 tyres and their markings as found on sidewalls of
old tyres:
OLYMPIC
ROAD GRIP 10 ply rating made in Australia
Centre
Divided Rims Only
Note: Narrow directional bar
V tread chevron, manufactured until early 1970's.
DUNLOP
TRAK GRIP 10 ply rating Made in Australia
RAYON
To fit
American Wheels
Note: Unusual curved wide bar
V chevron, post WW2 manufacture.
Good Year
Made in Australia
All Service
Sure Grip
D /|\ D
Note: wide bar directional V
chevron.
Michelin
Made in England
N Type
CC
W /|\ D
Note: curved directional wide
V bar tread, found on a Fordson WOT2D.
INDIA SUPER
TRACTION
Direction
of rotation when mounted on rear wheels > (arrow
pointing to closed end of chevron)
Reverse
when mounted on front wheels
Note: original WW2 vintage tyres
made in UK; two of them are marked RF; tread pattern is different to the
T24 Dunlops.
Fitting
tyres on CMP rims
Many Trak Grip tyres are marked "For
British rims" or "For American rims". The main difference is that one has
a 0º bead angle, while the other has a 5º bead angle. Various
restorers have reported contradicting experiences fitting tyres to 16"
CMP split rims. Some tyres fit without trouble, others only fit with lots
of trouble or after grinding the rim or shaving the tyre bead.
As "the jury is still out on this
problem", make sure you read up on the subject before embarking on fitting
tyres!
Further
reading on the subject
Read some interesting mailing list
and forum messages on the subject of 9.00-16 tyres at the:
With
special thanks to Richard Notton, Richard
Farrant and Mike Kelly for their assistance
in compiling this page.
|
Page created
10 December 2002
Updated
01 February 2003
Copyright
© 2000-2003 H.L.
Spoelstra - All Rights Reserved |
