The Triple Cycles supplied and manufactured Lightweight Shock Absorber Drum is suitable for fitting to all variations of the BSA/Triumph 3 cylinder engine that use the Triplex Primary Chain system. This item is interchangeable with the standard (iron) part. The weight of the standard part is 960 grams and the Triple Cycles part is only 350 grams.

57 4225A Lightweight Shock Absorber Drum, T150, A75 and X75 models

This shock absorber drum was originally developed when it became necessary to have manufactured the component in any form. Investigation of costing proved that, in reasonably small numbers, the material used had little relation to the cost of manufacture. I decided that a decreased weight would not disadvantage road use, and would positively advantage race use. This has proven in service to be the case and lightweight items have now been run perfectly satisfactorily for many years. Owners have reported reduced vibration (presumably due to better balance) and a sweater gearchange action.

This item is made from billets of HE30 aluminium, and is treated with the hard anodising process after manufacture. These processes have proven so satisfactory that now (December 2002) it is possible to buy aluminium clutch baskets for the T120 (duplex chain) and T140 (triplex chain) too, which are made using the same manufacturing processes. These Twin items are also kept in stock at Triple Cycles.

This item is held in stock under the following part number, which is the standard BSA/Triumph number with the suffix A.


At this time (December 2002) the purchase price of this item is:

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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 © 2002 Philip Pick
Version 0.20 Date December 2002