"may tend to" is correct and usable in written English.
You can use this phrase to indicate that something is likely or possible, for example: The current weather conditions may tend to favor a dry season.
As organisation grows personality may tend to disappear.
But you may tend to swing at better pitches.
In fact, the competition may tend to select overconfident people.
Thus, two-dimensional mating environments may tend to favor the evolution of contests.
Instead, each individual may tend to mutate at rates that selfishly increase its own relative fitness.
Hence, the warehouse design with CSP may tend to have lower investment cost.
Complexity concerns the extent to which STM structure may tend to amplify effects of change.
HENDRIK HERTZBERG: We refuse to answer on the grounds that it may tend to incriminate us.
Great law firms may tend to be wealthy, but not all rich law firms are great.
Plenty of those reading this may tend to view "Europe" in a benevolent light.
Some provisions of the law may tend to increase premiums in 2014.
