Competition Cub (T20C)

Competition Cub (T20C)

Not only did the 1957 year have a Tiger Cub with a new frame and suspension set up, there was also had a brand new Tiger Cub model added to the line up. The T20C 'Competition Cub'.

Its first public appearance being at the Paris Show, the new machine was based on the Gold Medal winning ISDT 'prototype' Cub the factory had built for Ken Heanes in 1956. The sales brochure declaring, 'It will appeal immediately as an efficient mount for the job, light in weight, with ample power and superb handling characteristics.' This model was the first to really emphasise the sporting pretentions of the Tiger Cub and set a trend that was to stay with Triumph's lightweight machine throughout its life.

Identical mechanically to the standard T20 Tiger Cub except for lower gearing, it could be ordered with either road or trials tyres for its 19 inch front and 18 inch rear wheels. The larger wheels giving increased ground clearance over the standard Tiger Cub model helped by a one inch increase in length to the front fork stanchions. There was a bracket on the rear sub-frame with which to hold the high level exhaust and more brackets reinforcing the bottom of the rear suspension units. A crankcase undershield was fitted, a froth tower added in the oil tank and the smaller T15 2 5/8 gallon petrol tank from the Terrier completed the look.

The first T20C model ran from 1957 until 1959 with UK and other market machines being in Crystal Grey and black and an Aztec Red and black option for USA models in 1958 and 59.


For the important USA market, a T20CA and T20CB model was introduced during 1958. The T20CA with high compression piston, close-ratio gear set, a low level exhaust and road tyres, the T20CB having a high level exhaust system.


Production T20C


30th October 1956


14th May 1959


27660 to 52974

(not continuous)

Production T20CA


8th October 1958


10th June 1959


46376 to 53780

(not continuous)



Single-cylinder OHV, unit construction


199cc (12.1 cu in)

Bore / Stroke:

63mm (2.480in) x 64mm (2.520in)


7 : 1 (T20C)

9 : 1 (T20CA/B)


10bhp (7.5 kW or 10.1 PS) @ 6000 rpm (T20C)


Amal 332/3 3/4in choke size or Zenith 17MXZ-CS5


Standard - valve clearances In & Ex 0.010in (cold)


Wet multiplate



Cycle Parts

Front Suspension:

Telescopic forks, hydraulic damped

Rear Suspension:

Swing-arm, twin shock absorbers

Front Wheel:

19 inch (WM1 rim)

Rear Wheel:

18 inch (WM2 rim)

Front tyre:

3.00 x 19

Rear tyre:

3.50 x 18


5.5 in dia. Single leading shoe drum front and rear

Petrol Tank:

2.625 UK gallons (3.15 US gallons or 11.92 litres)

Oil tank:

2.75 UK pints (3.3 US pints or 1.56 litres)


1/3 UK pint (0.4 US pints or 0.19 litres)

Primary Chaincase:

1/2 UK pint (0.6 US pints or 0.28 litres)

Front Fork:

1/8 UK pint (0.15 US pints or 0.07 litres)



Lucas Ignition Coil



Charging Type:

Alternator / Rectifier

Ignition Timing:

4° BTDC static. 28° fully advanced (T20C)

Points Gap:

0.014in - 0.016in

Spark Plug:

Champion L7 or equivalent

Spark Plug Gap: