We are often asked about how tight should Miragedrive chains and cables should be. Its a good question because if the chains are too loose there is a possibility of damaging sprocket teeth and if they are too tight performance will be impaired. MD180 users should be particularly mindful of not over-tightening the chains, especially the rear one.
To make sure you don't over-tighten the chains, push the pedal arms back and forth with your hands. If you are feeling resistance, it's likely the chains and or idler cable are too tight. Another way to see if they are too tight is to hold the drive in your hands and push one crank all the way forward while holding the other crank. If the drive naturally falls to the center, the tension is not too tight. If so, back off the nuts on the idler cable and or chains just a bit and try it again.
A good quick way to find out if the chains are too loose is to hold each pedal crank in each hand and try and pull them apart. If there is a lot of sloppy movement, chains and idler cable are likely too loose. The best way to know if your chains are too loose is to examine each chain and cable individually.
Factory built drives are usually spot on out of the packet, so check this when you buy your kayak so you can get a feel for how tight they should be. The front chain is marginally tighter than the rear chain (more important for MD180 drives). Check chain tension regularly. If a particular chain or cable tends to become loose on a recurring basis, the 1/4" nylock nuts securing them might need to be replaced. While not essential, it's also a good idea to use a bit of Loctite on the threads to help keep nuts in place.
Each chain and cable should be somewhat taught, but not over-tightened. Check how much sideways free play you have in the chains where the cable meets the swage (example above). Anything from 3 to 4mm in sideways play is about right for the front chain, 4-5mm for the rear chain and idle cable. Adjust fin tension by turning the 1/4" nylock nuts that secure the chains and to the drum. If a particular chain or cable tends to become loose on a recurring basis, the 1/4" nylock nuts securing them might need to be replaced.