Greenspeed Chain Gobblers

 

Greenspeed Chain Gobblers are an optional accessory, which automatically adjusts the chain length as the crank extension is moved in or out, to adjust for different rider leg lengths. This is very useful if there are people with different leg lengths who want to ride the same trike. They are particularly useful for dealers, as what used to take 10 minutes to adjust the chain length for different riders, can now be done in less than ten seconds! They are available for all Magnums, later GT Series II and Anura trikes. It may also be possible to retro fit the GT Gobblers to earlier GTs and GTOs, but the crank extension would need changing for a latter one with the special tag, as can be seen in the middle photo below.

  Please click on the thumbnails for large resolution photos.

                   

     
Magnum Gobbler              GT Gobbler Tag          Anura Gobbler      

                   
Magnum Gobblers. Specific Magnum Gobblers are now available, with chamfered brackets for the closer 35 mm Magnum boom boss spacing, the 45 mm Q/Rs, and the longer 460 mm moving idler pulley rod. The earlier GT Gobblers can also be used by drilling an extra hole in the fixed idler bracket to allow for the closer spacing of the boom bosses on the Magnum, chamfering the bracket to allow for the boss welding, and fitting the longer 45 mm Q/Rs instead of the 35 mm GT Q/Rs. See pic. below :-

 
Modified GT Gobbler  &  Fitting to Magnum

 
To fit either the Magnum Gobbler or the modified GT Gobbler, remove the two boom clamping Allen screws and replace with the two 45 mm Q/Rs to hold the fixed 10t idler pulley on straight bracket, as shown above. Then fit the moving 10t idler pulley on the long rod (460 mm ) to the special threaded tag underneath the bottom bracket with the stainless steel hex head bolt or cap screw, M8 x 35mm. Add enough chain for standard derailleur adjustment (see manual http://www.greenspeed.com.au/GT.SII.manual.pdf - page 11) with the chain looped around pulleys as shown, and with boom in middle of its travel (4" mark). Then fit and tighten the M8 locknut as shown in the GT5 Gobbler Tag photo above. Note that the lower chain tube may need to be shortened to accommodate the fixed 10 t chain pulley.

Check that there is enough front derailleur cable to accommodate the range of adjustment needed. For frequent adjustment over more than say 3" you may get better control of the front derailleur cable by putting it through the crank extension by drilling a couple of 5 mm holes, top and bottom, as shown below. For frequent adjustment between riders of all sizes, a better idea would be to use either a single chainring or a Schlumpf Drive, so that the front derailleur and cable is not required. www.schlumpf.ch

Tip:- Should there be any difficulty getting the Q/Rs tight enough to prevent the cranks from twisting under load, just put a drop of oil on the pivot of the Q/R levers, and work it into the bearing surfaces of the pins. 

   
Putting Front Derailleur Cable through Crank Extension

 
GT Gobblers. The GT Chain Gobblers use the plain straight bracket with the wider 45 mm hole spacing for the GT boom bosses, the 35 mm Q/Rs and the shorter 372 mm moving idler rod, as shown below:-
 

        
   GT Gobbler Parts       GT Gobbler Assembly      GT Gobbler Fitted

                   
                   
Anura Gobblers. The Anura Chain Gobblers have an "L" shaped bracket to accommodate the vertical spaced front frame clamp bosses, the longer 45 mm Q/Rs, and the longer 460 mm moving idler rod, as shown below:-
                   

     
Anura Gobbler Parts         Anura Assembly             Anura  Fitted       

                   
The Anura Gobblers can only be fitted to the latter model Anuras with a special attachment boss welded under the bottom bracket of the front frame from 2011 onwards.
                   

Updated IMS 13/08/2012