1

My kettwiesel 2006 trike is set up from the factory to use a shorter chain or a longer chain depending upon the riders height and is shipped that way from the factory. An option from the factory is a quick-adjust frame which includes a chain gobbler and a full length chain to fit a rider 6 ft 7 in tall. I believe there are other components to this quick adjust option but I'm not aware of what they are specifically. I know chain gobblers are not efficient but I would like shorter people to be able to ride my trike as I am 6'4. I was thinking of using an aftermarket gobbler and mounting it somewhere on the frame while using a full length chain. I bought the trike from a shorter Rider and now I have to lengthen the chain for me to ride it comfortably. Any ideas?

My trike is a standard model kettweasel with a 9-speed rear cassette and three speed front derailleur.

0

1 Answer 1

1

A "chain gobbler" is a recumbent device that takes up slack in a chain.

A regular bike derailleur gear system can do this with the cage in the rear derailleur, and they may have a capacity of perhaps 30 links total, but that also has to account for the gear combinations between big-big, and small-small.

A recumbent can send the chain completely back on itself in the area of the boom, something like this:

enter image description here

In this image is a common style, specifically a Terratrike part but most are similar. The pedals are to the right, the head tube is to the left. The yellow is the fixed boom and the smaller black tube is the inner boom.

The top straight run of chain is the power line that is under full tension from pedals and chainring, and the return line below is under far less tension. The lower "gobbler jockey wheel" is attached to the fixed frame and the other one is attached to the moving boom either permanently or by a clamp that can be repositioned

As you slide the boom in or out, the chain is "gobbled" by this extra zig-zag. Without this, the short-legged rider will have slack chain which can flap around and catch the wheel, pedal, ankle, or similar.

My understanding is that the gobbler is frequently either spring-loaded to help maintain chain tension, OR the top pulley's position can be set such that the rear derailler still adds enough tension.

Main downsides are added weight and losses in power - you're turning two extra wheels and even with larger 608 bearings inside there are still losses. Noise levels may increase slightly too.


As for extending the chain, depending on the wear it might be time for an all-new chain. Mine both take three separate road bike chains to get sufficient length. You should inspect the chain for wear, as well as the jockey wheels and the cassette. If your chain is already quite new, (under 200 km riding) then scabbing in an extra length of chain is probably fine, however the difference between the old/worn and the new section of chain means the chainrings and cassette will wear faster. Its really your call which you choose.

4
  • 1
    Criggie thank you for your detailed information about chain gobblers. What would the chain affect be if the gobbler was mounted only on the main frame tube and not both tubes?
    – Michael
    Nov 6, 2023 at 21:55
  • @Michael Having it over the adjustment in the boom means the slack in the chain is taken up as you pull the boom in/out. If the gobbler was only on the fixed main boom, you'd have to adjust it in a second step. Not a big deal really.
    – Criggie
    Nov 7, 2023 at 0:19
  • 1
    Thank you again for clarifying everything for me
    – Michael
    Nov 7, 2023 at 4:04
  • @Michael another thought - if these other riders are just having a test ride, then you may get away with blocks on the pedals, like how some old kid's big-wheel trikes have 4 sides for feet. Something like huskybicycles.com/mm5/graphics/00000002/366-397.jpg that you can slip on and clamp down with rubber band or velcro or whatever. Not great for long rides but for 10 minutes playtime at the local park would be perfect.
    – Criggie
    Nov 7, 2023 at 5:53

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.