Commission Number PlatesTriumph used a logic of alphabetical prefixes and suffixes to identify their range and series of each model and each model’s major assemblies (body, engine, gearbox and differential).
As an example TR4As from 1965 to 1967 were given ‘CTC’ (independent rear axle) or ‘CT’ (rigid rear axle) as their commission number prefix whereas TR5s were given ‘CP’.
Meanwhile in North America the TR250s used ‘CD’ as their commission number prefixes.
The number following the prefix was the sequence that each car was manufactured in.
Additionally ‘L’ followed this number to designate Left Hand Drive models and an ‘O’ was also used to denote a car that came originally fitted with overdrive.
These important numbers were stamped in 1/4" letters on a commission number plate fitted to each vehicle. Commission Numbers on all TR2, TR3 and TR3A models are stamped to a plate which is riveted to the right hand edge of the bulkhead.
With the introduction of the TR4 and TR4A the plate was moved to the left hand footwell top; finally on the TR5 and TR250 the plate was positioned on the left hand wheel arch.
Additionally from TR4A onwards each plate had stamped on it the original paint and trim colour scheme numbers for that particular vehicle. These numbers are explained in the paint section of this catalogue.