The two basic aims for alleviating chain-suck, are :
a) Tooth pressure-faces suitably shaped to disengage, even if loaded
b) Disengaging bottom teeth subjected to little or no chain load
Check for the obvious issues such as accident damage to chain-rings (bent), to teeth (bent) and to chains (twisted or tight links), and visible or reported mechanical inadequacies of particular drive-trains arising from poor design, materials, or manufacture. Repair affected components (if feasible), or replace them. Sometimes chain links become tight because of poor maintenance and riding through a lot of mud ; this can cause chain-suck ; the simple solution is to clean the chain thoroughly ; then strongly flex the stiff sections of chain (or stiff individual links) sideways/horizontally, to loosen the links ; and finally lubricate the chain well.
If necessary, use the Chain-Suck TEST to isolate the cause of the problem ; then implement the fix.
The most common solution to chain-suck is to install a new chain-ring :
Replace the worn chain-ring
(usually the granny) with an accurately machined component of strong hard material which is also tough. Avoid all aluminium; use only suitably specified steels (eg appropriate type of stainless steel), or use titanium. If it is a larger chain-ring (say 30 or more teeth), only then is a good aluminium alloy acceptable.
If the existing granny-ring is symmetrical,
it over to use its unworn trailing tooth faces, can also provide a good solution.
Rotate the fastening position of the chain-ring by one or more bolt-holes. This is a temporary solution which does not always work, but can be carried out on-the-trail, using only a single allen key wrench. It moves those teeth which are usually more highly indented or hooked, away from the critical high-load zones of the crank's cycle. If the chain-ring has special attachments or individually shaped teeth to ease gear changes, then such rotation can lead to less crisp gear changes. It might resolve 1-ring suck temporarily, but it can worsen (or alleviate) 2-ring suck.
Filing Tooth Profiles (see separate document) is a method for the technically proficient to reshape worn pressure faces of the teeth (tooth side-burrs are not the issue) to establish a better tooth profile. This method can also be used on-the-trail. If a new chain is to be installed, this method should not be used as a long-term solution.
When changing gear, reduce pedal pressure to reduce the driving forces of, and hence the opportunity for, this type of chain-suck.
The next four options can be used individually or in combination to adjust the rotational alignment of teeth on adjacent rings ; this will improve matters if the change is in the right direction, but will worsen matters if it is not.
Install a different granny ring and/or middle ring with different tooth shape, and/or also a different manufactured alignment of teeth along its circumference
Install a ring with a different number of teeth, to change the tooth-ratio of adjacent rings, and hence the relative alignment of teeth
Rotate the fastening position of the chain-ring by one or more bolt-holes, which will change the relative alignment of teeth.
Adjust the adjacent granny/middle rings so that the small amount of play which exists in their bolt-holes is used to fasten the rings at that extreme of play which reduces problems
For a set of new chain-rings, for which the problem just cannot be resolved by any of the above measures :
It may be necessary ultimately to get a different make/design for the complete set ; this may also involve a different set of cranks ; it is advisable to get a well matched set, with tooth ratios and tooth shaping/ramping generally known not to suffer this problem, and from a single manufacturer.