This page will tell you something about the  tandem tricycle conversion

The Newton tandem tricycle conversion grew out of the Newton tricycle conversion which has proved a very successful design.  In terms of handling, the particular needs of a tandem trike are that it should be stable in a straight line and steer smoothly and without undue effort.  Further, it should not wander or wobble as a result of irregularities in the road.  Experience gained from the development of the solo conversion and general knowledge of steering geometry led to a machine with a wider axle than the solo, for increased lateral stability, and with the front axle moved back about 10" (25cm) which brings the greatest width nearer to the centre of gravity and has the useful effect of reducing the wheelbase, which improves manoeuvrability in confined spaces.  This does not, as you might think from looking at it, mean that it tips onto its nose when you apply the brakes - it is quite stable, even when ridden solo.  When cornered at any reasonable speed, it does not lift a wheel, or even feel as though it might. Side view of a
        Newton tandem conversionThe conversion main tubes are Reynolds 531, and construction is by bronze welding.  It fixes to the tandem cycle frame by means of clamps at the steering head and front bottom bracket.  Tandem frames vary quite widely in detail design at these points, and in order to ensure a perfect fit which still allows for front chain adjustment, it is necessary to have (at least) the frame for which the conversion is intended available during the manufacturing process.  In addition to clamped-on conversions, we can also do a permanent welded conversion to a tandem frame.  This produces a neater finish, is slightly lighter and slightly stronger, but is of course very difficult to remove, should that be necessary.  We can convert an aluminium frame with a  clamped on steel conversion like the one shown here.  We don't have the facilities to do welded aluminium conversions.

The front wheels carry at least twice the weight of those on a solo trike, and so need to be strong.  Wheel sizes available as standard are 700c, 26" or ETRTO 559 (ATB size), and for strength we recommend the use of eyeletted box-section alloy rims together with 13/14g (2.3/2.0mm) spokes.  The standard front brakes are Avid mechanical discs on Hope hubs which give dependable braking performance for normal loads and speeds.   These can be supplied with larger diameter discs for better cooling if you intend heavy touring in hilly areas.

The conversion shown here is one which was completed in early 1999Front view of the same conversion and is built on a Thorn Voyager tandem frame and was supplied at the customer's request without saddles (we assume they intended to fit their own!).  The front view clearly shows the extra width necessary for a tandem trike, this one in fact looks even wider in this pictures than it really is; the front track is around 33" (84cm).

The complete conversion set includes wheels, tyres, brakes, steering parts and head bearings and adds about 8 Kg to the weight of the tandem when fitted.  Delivery should be around 6 weeks from order, and the conversion costs UK£1500 in standard form.  Additional fittings or modifications can be undertaken, these will affect the cost and, maybe, delivery time.

Below is a picture of a welded conversion on a Dawes Galaxy Twin, which is a neater job as it doesn't have clamps.

welded conversion

And a final picture of the special head clamp arrangement used on an aluminium-framed dawes tandem.

head clamping on ally frame

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