The GT20 is a completely new frame design from Greenspeed. We are using the rectangular cross section main tube as used on the Anura, which both stronger and lighter than the round tube used on the Magnum. And to make further gains is strength and weight we have eliminated the welds in the main tube and the cross member, by making the front main tube in one piece, and cross member also in one piece, and curved so that it comes closer to the seat to enable the rider to mount and dismount easier. The frame material is 7005 aluminium alloy, which is stronger than the more commonly used 6061 aluminium alloy and stronger than mild steel, yet only 1/3 the weight. The seat is the same material, but standard size, instead of the large seat used on the Magnum, thus it is lighter, and has lighter and simple struts for angle adjustment, yet the same Q/R adjustment at the front for height adjustment. The frame is hinged like the earlier GT3, and the Magnum, so that rear half can be folded over the front half to reduce the size enough to fit in the trunk of a car. The rectangular main tube also makes it easier to adjust the trike for leg length, as the cranks are now self-aligning, plus the cranks will no twist in the frame, if the pinch bolts or Q/R for leg length adjustment have not been done up really tight. We have also welded a boss to the frame to take the fixed idler for the optional Chain Gobbler, which automatically adjusts the chain length, as the cranks are moved in and out, to suit riders with different leg lengths.
Yet another feature of the GT20 frame, is the ability to change frame sizes. The standard frame will take riders with an X-seam from 41 to 51 inches, or from about 5’ 3” to about 6’ 5” in height. However, as the boom clamp is an external clamp, rather than part of the frame, the main tube can be shortened as much as 6” to allow riders with an X-seam as small as 35 inches or about 4’ 6” in height.