Gearbox Ratio Conversions

The Triple Cycles gearbox conversion kit provides an economical method of producing a close ratio gearbox based on Triumph 5-speed standard parts

It can be seen from the table of ratios below that fitting the four replacement gears (normally called mainshaft and layshaft 5th and 4th) results in a gear cluster having internal ratios of 1, 1.12, 1.25, 1.64 and 2.31. Although the layshaft fourth gear is 17T in a standard gearcluster and 17T in the conversion kit, it must be changed due to the change in gear tooth form.

These parts are suitable for fitting in Triumph Trident and Triumph Twin (B-Range) applications. They can also be used when a 5-speed gearcluster in fitted in a Triumph or Nourish pre-unit gearbox shell.

The conversion is designed to be used with the late standard Triumph gearcluster, produced from 1973 onwards. If in doubt as to the suitability of any 'donor' standard parts please contact Triple Cycles for further advise.

Gear Standard Triumph 5-speed With Triple Cycles Conversion Quaife (MK2) 'Close Ratio' (for reference)
MainshaftLayshaftInternal RatioMainshaftLayshaftInternal RatioMainshaftLayshaftInternal Ratio

Further Gearbox Conversion Parts

Alternative gears are now available to further alter the ratios of the 1st and 2nd gears in a gearbox based on Triumph 5-speed standard parts.

Layshaft 2nd is available at 20T, and Layshaft 1st is available at 22T. These gears are produced to run with the existing (standard) mainshaft (combined) 1st/2nd gear.

If fitted to a standard cluster the overall ratio of 2nd would change from 1.84 to 1.75, and the overall ratio of 1st would change from 2.58 to 2.37.

If fitted to a cluster that is fitted with a Triple Cycles conversion the overall ratio of 2nd would change from 1.64 to 1.56, and the overall ratio of 1st would change from 2.31 to 2.11.

These gears can be fitted independently of each other, and allow a rider to tune the 1st and 2nd gear ratios for any particular circuit. The higher 2nd gear in particular will be of benefit to riders of smaller capacity machinery, where the drop from 3rd to 2nd was a little wide under certain circumstances.

These items is held in stock under the following part numbers. Individual spares of the overall conversion are available.


At this time (September 2003) the purchase prices of these items are:

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Triple Cycles
95 Wanstead Park Road
Telephone: +44 20 8215 4583 (answerphone only, unless by arrangement)
Facsimile: +44 20 3137 2295

Copyright © 2000 Philip Pick
Version 0.1 Date December 2000